DGL-CW by Wonder Laboratories

EFFECTIVE

• Dyspepsia. Oral calcium carbonate is approved by the US Food and Drug Administration (FDA) as an antacid. Details: Taking calcium carbonate orally as an antacid is effective for treating dyspepsia (1843). Calcium carbonate has FDA approval as an antacid.
• Hyperkalemia. Intravenous calcium gluconate is approved by the US Food and Drug Administration (FDA) for preventing hyperkalemia-induced cardiac abnormalities. Details: Administering calcium gluconate intravenously can reverse electrocardiographic changes and arrhythmias induced by hyperkalemia (12946). Intravenous calcium gluconate is FDA-approved for preventing hyperkalemia-induced cardiac abnormalities.
• Hypocalcemia. Oral calcium treats and prevents hypocalcemia. Intravenous calcium is used to treat severe hypocalcemia. Details: Taking calcium orally is effective for treating and preventing hypocalcemia. Intravenous calcium gluconate, acetate, gluceptate, or chloride is effective for severe hypocalcemia or hypocalcemic tetany (12928).
• Kidney failure. Oral calcium carbonate or calcium acetate is used as a phosphate binder during kidney failure. Details: Taking calcium carbonate or calcium acetate orally is effective as a phosphate binder. Calcium acetate (PhosLo) appears to control hyperphosphatemia better than sevelamer (Renagel) (12943,12944,38990). Calcium citrate is not recommended for this purpose because it increases aluminum absorption and does not bind phosphate as efficiently as calcium acetate or calcium carbonate (21631). Some clinical research also shows that taking calcium orally reduces blood pressure in patients with kidney failure (975).

LIKELY EFFECTIVE

• Corticosteroid-induced osteoporosis. Oral calcium in combination with vitamin D prevents bone density loss that occurs during long-term treatment with corticosteroids. Details: Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term (982,1046,1830,1831,1832,4462,4463,4464,4465,4466)(4467,12945,38493). One specific product used in clinical research is Oscal (Marion Merrel Dow Inc.), which contains elemental calcium 500 mg per tablet plus vitamin D 125 IU per tablet (982). Another product used is Oscal 250 + D (SmithKline Beecham Healthcare), which contains elemental calcium 250 mg and vitamin D 125 IU per tablet (1046).
• Hyperparathyroidism. Oral calcium reduces parathyroid hormone levels in patients with secondary hyperparathyroidism due to kidney failure. Details: Taking calcium orally reduces parathyroid hormone levels in patients with kidney failure and secondary hyperparathyroidism (1827,1828,1829,39174,39425). In elderly women, the combination of calcium and vitamin D reverses secondary hyperparathyroidism and reduces hip fracture risk (8818). Also, population research suggests increased calcium intake from the diet and supplements reduces the risk of primary hyperparathyroidism in women. Supplemental intakes of at least 500 mg/day and dietary intakes of approximately 1100 mg/day are considered to be protective (91353).
• Osteoporosis. Adequate calcium intake, from the diet and/or supplements, is recommended for the prevention and treatment of osteoporosis. Details: The Bone Health and Osteoporosis Foundation (BHOF) recommends ensuring adequate calcium intake in line with the recommended dietary allowance (RDA) by age, along with adequate vitamin D intake, for the prevention and treatment of osteoporosis in adults over 50 years of age. Supplementation can be used to augment dietary intake when adequate dietary intake is not feasible (109425). In the US and Canada, foods containing at least 200 mg calcium with less phosphorous content than calcium can be labelled with a health claim regarding the relationship between adequate calcium intake and a reduced risk for osteoporosis (11940,102148). However, calcium supplementation is not recommended specifically for the primary prevention of osteoporosis. The US Preventive Task Force (USPSTF) states that the current evidence is insufficient to assess the balance of benefits and harms of vitamin D and calcium supplementation, alone or in combination, for the primary prevention of fractures in community dwelling adults without osteoporosis (95695). Also, calcium supplements do not seem to be effective for preventing loss of bone mineral density (BMD) during lactation (988), in patients who have had bone marrow transplantation (1817), or in patients who have had renal transplantation (4823,38736,38871). Maximal bone growth occurs in the teenage years, and then BMD in females remains relatively constant until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In males, this occurs several decades later. Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many Americans (2571,2578). One meta-analysis of randomized controlled trials in healthy children 7-14 years old shows that fortifying food with calcium 250-1000 mg daily for up to 24 months modestly improves femoral neck BMD, but not hip or spine BMD. However, the included trials did not supplement vitamin D (107232). During the 5 years immediately after menopause, calcium supplementation has very little effect on bone loss (2569,2570,2575,2576). The rapid loss of estrogen causes a high bone resorption rate, which increases serum calcium levels and therefore decreases intestinal absorption of calcium (2570). After this period, the typical rate of bone loss is 2% per year (2572,2576). Taking calcium 1000-1600 mg daily as carbonate, citrate, lactate gluconate, or citrate malate salt decreases this rate by 0.25% to 1% annually (977,979,981,2569,2571,2572,2575,2576,2578,6850)(38978,38980,39064). The greatest reductions (1% or more) are seen in the first 1-2 years of supplementation when bone remodeling foci can be filled (2569,2576). After this period, the differences in rate of loss between supplemented and non-supplemented females are closer to 0.25% per year (2569,2577). A meta-analysis of clinical evidence suggests that there is no additional benefit after 4 years (38980). Small clinical studies have found that continuous calcium supplementation at an average daily dose of 1050 mg, started after menopause and continued for 1.5-4 years, may reduce fracture rates by 26% when compared with no calcium supplementation. The largest of these studies was conducted in nursing home residents who also received daily vitamin D; the benefits of calcium, specifically, are unclear (39386). Some research also suggests that calcium and vitamin D improves primary prevention of osteoporotic fractures in some older individuals with osteoporosis, particularly the elderly and those who are no longer community dwelling (12930,38875,38849,39026,109471). However, not all research is positive. One large clinical trial in elderly adults with a low-trauma fracture show that taking calcium 1000 mg daily with or without vitamin D 800 IU daily for 2-7 years does not reduce the risk of a second fracture when compared with placebo (13073). Another clinical study shows that taking calcium 1000 mg daily plus vitamin D 800 IU daily does not prevent a second fracture in elderly patients, or prevent a first fracture in elderly patients with other risk factors such as low body weight (less than 58 kg, 127.6 pounds), smoking, family history of hip fracture, or fair or poor self-reported health (12929). Also, some exploratory research suggests that supplements may need to be continued indefinitely; in adults over 68 years of age, any effects of 2 years of calcium supplements on BMD appear to be lost within 2 years after discontinuing supplements (6853). Calcium has additive effects when used with other agents such as vitamin D, estrogens, or calcitonin. Whereas calcium alone generally reduces or prevents loss of BMD, combination with other agents can produce small increases in BMD ranging from 0.3% to 3.3% depending on the combination and dosages used (978,980,1836,2570,2571,2572,2576). However, one meta-analysis in healthy adults shows that fortifying foods with calcium 250-1000 mg daily, in conjunction with vitamin D supplementation, for up to 24 months does not improve BMD when compared with control (107232). The full potential of osteoporosis treatments cannot be realized without adequate calcium intake (2569,2570,2571,2572). Advise patients taking agents such as estrogens, calcitonin, bisphosphonates, or raloxifene (Evista) to ensure that their daily calcium intake meets the RDA. Use supplements if necessary. The usefulness of calcium in preventing osteoporosis in males is not as well-studied. Some observational research has found that calcium 870 mg daily is not associated with changes in BMD and bone loss in males (97201). However, clinical evidence suggests that taking calcium 1000 mg daily for 2 years might improve trabecular or cortical bone mass by 2% to 4% (980,8827,8873). Dietary supplementation with calcium and vitamin D seems to moderately reduce bone loss measured in the femoral neck, spine, and total body, and seems to reduce the incidence of nonvertebral fractures in older patients with osteopenia or low BMD (980).
• Premenstrual syndrome (PMS). Adequate calcium intake seems to prevent symptoms of PMS. Details: There seems to be a link between low dietary calcium intake and symptoms of PMS (2004,6847,39007). Taking calcium 1000-1336 mg daily seems to significantly reduce depressed mood, water retention, and pain, especially if daily calcium intake is inadequate (1822,1823,1824,2004,95821). Calcium carbonate 1200 mg daily seems to decrease PMS symptom scores by about 18% when compared with placebo (1822). Increasing dietary calcium intake is also associated with a decreased risk of developing PMS. Consuming an average of 1283 mg of calcium per day from foods is associated with about a 30% lower risk of developing PMS compared with consuming an average of 529 mg daily (13094); however, taking calcium supplements does not appear to be associated with the risk of developing PMS.

POSSIBLY EFFECTIVE

• Colorectal cancer. Oral calcium seems to be beneficial for preventing colorectal cancer, especially in those with adequate vitamin D levels and normal body mass index (BMI). Details: Population studies have found that increased intake of dietary or supplemental calcium is associated with a reduced risk of colorectal cancer and colorectal adenomas (1047,8820,12120,38951,98898,98899). Clinical trials and meta-analyses of clinical research also show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29% (970,12118,12950,15267,34596,38718,39042,95817). However, not all research has been positive. Some meta-analyses of clinical research or observational studies suggest that taking calcium does not reduce the risk of familial adenomatous polyposis or colorectal cancer (34596,39042,39349). Other contradictory research suggests that postmenopausal females who take calcium 1000 mg daily plus vitamin D 400 IU daily do not have a reduced risk of developing colorectal cancer (14290); however, this finding may not be reliable due to the high baseline intake of calcium in study participants. The reason for these conflicting findings is not entirely clear. Vitamin D might be an important factor. People with lower than average vitamin D levels do not seem to get any benefit from calcium supplements (12118). Also, one meta-analysis of previous trials suggests that taking calcium 1200 mg daily reduces the risk of colorectal adenomas in people with a normal BMI, but not in those who are overweight or obese (99715). Despite this conflicting evidence, the US Food and Drug Administration (FDA) approved a qualified health claim in 2005 stating that calcium supplements may reduce the risk of colorectal cancer and colorectal adenomas. However, the FDA has determined that there is little scientific evidence to support this claim (102366).
• Fetal bone mineralization. If calcium intakes are low during pregnancy, oral calcium seems to be beneficial for increasing fetal bone density. Details: With low dietary calcium intake (less than 562 mg elemental calcium daily) during pregnancy, calcium supplementation increases fetal bone mineralization and density. However, calcium supplementation does not offer any additional benefit if calcium intakes are adequate (3263,3264).
• Hypertension. Oral calcium seems to reduce blood pressure by a small amount. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies show that intake of calcium supplements or dietary calcium modestly reduces blood pressure in patients with or without hypertension, usually around 1-2 mmHg. Calcium seems to be more effective for certain subpopulations of patients, such as salt-sensitive people and patients with low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221). Also, a meta-analysis of clinical research shows that calcium intake during pregnancy reduces systolic blood pressure in offspring by 1-2 mmHg (38852). However, a large-scale clinical trial in postmenopausal females shows that taking vitamin D (cholecalciferol) 400 IU daily in combination with elemental calcium 1000 mg daily does not lower blood pressure or reduce the risk of developing hypertension (16714). Additionally, a meta-analysis of 8 clinical trials shows that taking calcium in combination with vitamin D for up to 7 years has no effect on blood pressure (98861). The validity of this finding is limited by the poor methodological quality of the included studies. Some observational research suggests that calcium can reduce the risk for hypertension. Population research in females aged 45 years and older suggests that higher intake of calcium from both diet and supplement sources is linked to a lower risk of developing hypertension when compared to lower calcium intake (14265). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim stating that calcium supplements may reduce the risk of hypertension. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102367).
• Osteomalacia. Oral calcium seems to reverse osteomalacia caused by very low calcium intakes. Details: Osteomalacia is commonly caused by vitamin D deficiency; however, very low calcium intake can also lead to osteomalacia in children and adults. Calcium supplementation can reverse osteomalacia caused by calcium deficiency. Along with appropriate vitamin D supplementation, individuals at risk of osteomalacia need sufficient calcium intake (94819).
• Pre-eclampsia. Oral calcium seems to reduce the risk of pre-eclampsia in high risk pregnancies, especially if calcium intakes are low. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces pregnancy-related hypertension and pre-eclampsia (973,1833,8828,39043,39319,39426,96480). Calcium appears to reduce the risk of pre-eclampsia by about 50% when compared with placebo. One meta-analysis of 19 controlled trials involving over 29,000 pregnancies found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (96480). Calcium appears to have the greatest effect in individuals at high-risk of pre-eclampsia or with low calcium levels, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,96480,99714). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim regarding the use of calcium supplements to reduce the risk of pregnancy-induced hypertension and pre-eclampsia. However, due to the limited and conflicting research available at that time, the FDA stated that this outcome was highly unlikely. Since then, large, high-quality clinical research has supported this finding. In fact, in 2016 the World Health Organization (WHO) released a recommendation to prescribe oral calcium supplementation 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low, in order to prevent pre-eclampsia (97347).
• Rickets. Oral calcium seems to reverse rickets caused by very low calcium intakes. Details: Rickets is commonly caused be vitamin D deficiency; however, very low calcium intake can also lead to rickets. Calcium supplementation can reverse rickets caused by calcium deficiency (94819). A small clinical study in children with nutritional rickets shows that taking calcium 500-2000 mg daily for 24 weeks improves radiographically measured rickets caused by calcium deficiency. Rickets seems to improve more rapidly with calcium 1000 mg compared to calcium 500 mg. However, increasing the calcium dose to 2000 mg daily is not more beneficial than calcium 1000 mg daily (98904).
• Tooth retention. Oral calcium with vitamin D seems to help with tooth retention in the elderly population. Details: A clinical trial in the elderly population shows that taking calcium citrate malate 500 mg daily along with vitamin D3 (cholecalciferol) 700 IU daily orally for 3 years reduces the risk of tooth loss by about 52% when compared with placebo (8816).

POSSIBLY INEFFECTIVE

• Breast cancer. Oral calcium does not seem to be beneficial for breast cancer prevention. Details: Although some population research disagrees (15631,39041,95811,107237), most research shows that increased calcium intake is not associated with a reduced risk of breast cancer (15631,16715,98895,107236,107237). Subgroup analyses of population research suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237). Another subgroup analysis in a large meta-analysis of population research also suggests that dietary intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most other research has not evaluated the effects of calcium supplementation or intake on breast cancer subtypes. The best evidence to date, from a large scale clinical trial (Women's Health Initiative), shows that taking vitamin D (cholecalciferol) 400 IU daily plus calcium 1000 mg daily for 7 years after menopause does not reduce the risk of developing invasive breast cancer at the end of the study and 5 years after the end of the intervention (16715,98895).
• Fractures. Although oral calcium prevents fractures in osteoporosis, most evidence shows that calcium does NOT prevent factures in people who do not have osteoporosis. See Osteoporosis discussion for more information on the use of calcium for this purpose. Details: The most recent and robust meta-analysis of clinical research shows that calcium supplementation with or without vitamin D is NOT associated with reduced fractures in older adults without osteoporosis (95822). A large-scale study in postmenopausal females aged 50-79 years suggests calcium 1000 mg plus vitamin D 400 IU daily for 7 years only modestly improves bone mineral density (BMD) and does not significantly reduce fracture risk. This lack of effect may have been due to low adherence to the treatment regimen. In those who were 80% adherent, the combination of calcium plus vitamin D reduced the risk of hip fracture by about 29% (14282). Also, some clinical research shows that taking calcium carbonate 1000 mg and vitamin D 400 IU for 5 years does not attenuate loss of height after menopause when compared with placebo (95810). Additional meta-analyses of clinical and observational evidence suggest that calcium supplementation is not associated with a reduced risk of vertebral or nonvertebral fractures, such as hip fractures (38589,38888,98895). Some other research has suggested that calcium in combination with vitamin D reduces fracture risk in older patients without osteoporosis (980,1836,8818,12930,12933,12952,38849,102145,107235); however, this research is confounded by a number of variables, including the presence of hormonal therapy and differing levels of fracture risk at baseline (1836,8818,95822). Conflicting findings on this topic might also be due to genetic differences in patient populations. A population analysis of the Women's Health Initiative study found that, in older females with the lowest genetic susceptibility to low bone mineral density (BMD), taking calcium with vitamin D is associated with a reduction in fracture risk. However, in females with a higher genetic susceptibility to low BMD, there is no association between supplementation and fracture risk. This might be because individuals with a lower susceptibility to low BMD are also more responsive to calcium and vitamin D supplementation (97357). As of April 2018, the U.S. Preventative Services Task Force (USPSTF) concludes that there is insufficient evidence to determine whether supplementing with vitamin D >400 IU daily along with calcium >1000 mg daily is safe and effective for preventing fractures in community dwelling adults without vitamin D deficiency, osteoporosis, or a history of fracture. USPSTF recommends against supplementing with calcium 1000 mg daily or less along with vitamin D 400 IU daily or less for preventing primary fractures in community-dwelling postmenopausal females (95695).
• Obesity. Oral calcium does not seem to improve weight loss. Details: Observational research has found that adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese when compared to people with high calcium intake (12124,12125,12126,12127,14265). Additional observational research has found that increasing calcium intake is associated with weight loss in females; the results in males have been conflicting (12127,15602,15603). Despite these findings from observational research and a few small clinical studies (12128,15397,14438,98905), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). The most recent meta-analysis of 20 clinical studies shows that daily dietary and supplemental calcium intake that meets the dietary reference intake (DRI) of 1000 mg or more daily does not increase weight loss in overweight individuals or patients with obesity when compared with intake below the DRI (95813). An older meta-analysis of 13 clinical trials also shows that increased dietary and supplemental calcium intake does not increase weight loss (15605).
• Overall mortality. Oral calcium does not seem to reduce overall mortality. Details: While some population research has found that calcium taken in combination with vitamin D in older females is associated with a lower risk of death (97353), most evidence shows that calcium, with or without vitamin D, has no effect on all-cause mortality (93533,97308).

INEFFECTIVE

• Cardiovascular disease (CVD). Oral calcium does not reduce the risk of developing CVD and may actually increase risk in some patients. Details: Clinical research shows that calcium does not decrease CVD risk. Several separate meta-analyses of clinical and population research involving over 50,000 patients show that taking calcium 600-1200 mg daily for up to 7 years does not reduce the risk of CVD-related outcomes, including stroke and myocardial infarction, cardiovascular death, or overall mortality (39018,91350,92994,93533,97308,98902,107231,107233). No association was found between total dietary or supplemental calcium intake with or without vitamin D and the risk of CVD or mortality (91350,93533,97308). In fact, some population and clinical research has found that when calcium is used alone or with vitamin D, there is an INCREASED risk of CVD and coronary heart disease (38077,107233). However, other clinical research disagrees (93533). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of CVD and coronary heart disease by 1.1-1.2 times when compared with control. However, the majority of the included research evaluated postmenopausal females and it is unclear if this finding is applicable to other populations (107233).
• Chemotherapy-induced peripheral neuropathy. Intravenous calcium does not prevent nerve pain in patients given oxaliplatin. Oral calcium has not been evaluated for this purpose. Details: While pooled analyses of cohort studies and randomized controlled trials suggest that calcium and magnesium infusion decreases the incidence of oxaliplatin-induced neurotoxicity, a meta-analysis of only randomized controlled trials shows that the infusion has no effect in preventing neurotoxicity (90028,90029,90031). Additionally, clinical trials show that administering calcium gluconate 1 gram with magnesium sulfate 1 gram intravenously immediately before, or before and after, the administration of a single oxaliplatin cycle (90005), or over the entire 6-cycle course of oxaliplatin, does not improve symptoms of neurotoxicity when compared with placebo (96474).
• Myocardial infarction (MI). Oral calcium does not prevent MI. When taken in the absence of vitamin D, oral calcium may increase the risk of MI. Details: Population research has found that increased dietary intake of calcium is associated with a decreased risk of MI (91350). However, a 2010 meta-analysis of clinical research shows that taking calcium at a dose of at least 500 mg daily is associated with an approximate 30% INCREASE in the risk of MI in patients over the age of 40. According to this analysis, one additional case of MI will occur for every 69 patients that take calcium for 5 years (17482). A more recent meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of MI by 1.2 times when compared with control. However, the majority of the included research studied postmenopausal females and it is unclear if this finding is applicable to other populations (107233) In contrast, other meta-analyses of clinical research have shown that taking calcium for up to 7 years is NOT associated with an increased risk of MI, including a meta-analysis that only included postmenopausal females (93533,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of MI in postmenopausal females (93533). Also, the association between calcium supplementation and MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. It is unclear if oral calcium is beneficial for alcohol use disorder. Details: Preliminary clinical research shows that taking calcium carbonate 800 mg and vitamin D 200 IU orally daily for 14 days modestly reduces alcohol craving scores and withdrawal scores when compared with placebo in adults with alcohol dependence that are undergoing withdrawal. Taking calcium carbonate did not reduce the need for diazepam; however, the study may have been inadequately powered to detect a difference between groups (107234).
• Atherosclerosis. It is unclear if oral calcium is beneficial for atherosclerosis. Details: A population study has found that taking calcium 1.2 grams daily for 3 years has no effect on carotid intima thickness or carotid atherosclerosis incidence. A total calcium intake (dietary and supplemental) of at least 1794 mg daily in older females may be associated with a decreased risk of carotid atherosclerosis when compared with a total calcium intake below 1010 mg daily (97351).
• Autism spectrum disorder. It is unclear if oral calcium during pregnancy is beneficial for reducing the odds of autism spectrum disorder in the offspring. Details: A small observational study found that calcium supplementation during pregnancy is associated with a 52% reduced odds of an autism spectrum disorder in the offspring (98900).
• Cancer. Oral calcium alone does not seem to prevent cancer. It is unclear if oral calcium with vitamin D is beneficial for preventing cancer. Details: Taking calcium alone does not seem to significantly reduce the risk of cancer (12118,15629). The role of calcium in cancer prevention when taken along with vitamin D is controversial, as conflicting results exist. One clinical trial shows that healthy postmenopausal females who take supplemental calcium 1400-1500 mg daily plus vitamin D3 (cholecalciferol) 1100 IU daily have a 60% lower relative risk for developing cancer of any type. Approximately 25 postmenopausal females would need to take this combination for 4 years to prevent one occurrence of cancer (15629). However, a more recent clinical study shows that healthy postmenopausal females who take supplemental calcium 1500 mg daily plus vitamin D3 (cholecalciferol) 2000 IU daily do not have a reduced risk of cancer at 4 years (93943). Reasons for the disparate results are not entirely clear. The discrepancies do not appear to be related to baseline vitamin D levels or different study populations. It is possible that, given the 10-year time lapse between the two publications, the discrepancies result from differences in cancer detection capability. Also, since cancer risk was a secondary outcome measure in the earlier study and a primary outcome measure in the more recent study, it is possible that the discrepancies result from differences in statistical methodologies. The effect of vitamin D and calcium on cancer risk in males and younger patients is not known. There is also interest in using calcium for reducing the risk of hematological malignancies. An analysis of the Women's Health Initiative study shows that taking calcium 1000 mg daily in combination with vitamin D3 400 IU for up to 10 years is associated with a 20% reduction in the risk of hematologic malignancies when compared with placebo. However, no effect on hematologic malignancy related mortality was seen (97354).
• Depression. It is unclear if oral calcium is beneficial for depression prevention. Details: Population research has found no association between a higher dietary intake of calcium and the risk of depression when compared with a lower dietary intake of calcium (96480).
• Diabetes. It is unclear if oral calcium is beneficial for type 2 diabetes prevention. Details: Some population research has found that a higher intake of calcium from diet or supplements, alone or in combination with vitamin D, is associated with a lower risk of developing type 2 diabetes when compared with lower calcium intake (14265,16713,96473). However, population research is often limited by confounding variables. For example, one analysis found that any beneficial effect might be influenced by concomitant magnesium intake (96473). Furthermore, other population research has found that serum calcium levels higher than 9.6 mg/dL are associated with greater risk of developing diabetes in Chinese adults with osteoporosis. This study is limited because it was not determined whether increased serum calcium was due to increased calcium intake or another factor such as parathyroid function (95815).
• Dysmenorrhea. It is unclear if oral calcium is beneficial for reducing pain associated with dysmenorrhea. Details: Clinical research shows that taking calcium carbonate 1000 mg with vitamin D 5000 IU daily for three menstrual cycles does not reduce pain when compared with placebo in patients with primary dysmenorrhea (95821). However, calcium carbonate 1000 mg taken alone seems to reduce pain when compared with placebo.
• Endometrial cancer. It is unclear if oral calcium is beneficial for endometrial cancer prevention. Details: A meta-analysis of population research suggests that calcium supplements may reduce the risk of endometrial cancer, but dietary calcium does not seem to have any effect (38893).
• Fall prevention. It is unclear if oral calcium with vitamin D is beneficial for preventing falls. Details: Research suggests that calcium in combination with vitamin D, but not calcium alone, might prevent falls by decreasing body sway and normalizing systolic blood pressure (6362,11939,39038). Some experts think the combination of calcium and vitamin D may be important (11916). Preliminary clinical research in adults residing in a health care facility shows that taking vitamin D supplements while increasing dietary calcium and protein for 2 years reduces falls by 11% when compared with standard diets. Intervention diets were supplemented with milk, yogurt, and cheese to provide calcium 1142 mg and protein 69 grams daily (107235). There might also be different effects in females compared to males. In one study, females aged 65 years or older who took vitamin D 700 IU plus calcium citrate 500 mg daily over a 3-year period had a 46% lower risk of falling. However, this combination did not decrease falls in males (14291).
• Fluorosis. Oral calcium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking calcium orally, in combination with ascorbic acid (vitamin C) and vitamin D, seems to be effective for reducing excessive fluoride levels in children and improving symptoms of fluorosis in children aged 6-12 years (990).
• Heart failure. It is unclear if oral calcium in combination with vitamin D is beneficial for preventing heart failure. Details: Based on a secondary analysis of a large-scale clinical trial (Women's Health Initiative), taking calcium 1000 mg with vitamin D 400 IU daily does not reduce the risk of heart failure in the overall population or in individuals at high risk. However, in a subgroup of postmenopausal females without risk factors for heart failure, calcium and vitamin D supplementation might reduce the risk of developing heart failure by about 37% (97307).
• Hypercholesterolemia. It is unclear if oral calcium is beneficial for hypercholesterolemia. Details: Some evidence shows that taking calcium carbonate 400 mg three times daily reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% after 6 weeks of treatment when used in combination with a low-fat diet (American Heart Association Step 1) (2557). In contrast, a study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years might INCREASE total cholesterol levels by about 12 mg/dL when compared with placebo. This same study showed an association between calcium supplementation and an increase in total cholesterol levels and carotid intimal thickness in postmenopausal females, but not premenopausal females (97350). A recent meta-analysis of randomized controlled trials which included both healthy patients and patients with dyslipidemia shows that taking calcium 500-2000 mg daily and vitamin D 200-7142 IU daily modestly improves HDL cholesterol and triglyceride levels, but not LDL cholesterol levels, when compared with placebo. Subgroup analyses suggest that calcium and vitamin D supplementation is more effective in patients with dyslipidemia at baseline. It is unclear if this effect is due to calcium, vitamin D, or the combination (107227). However, other research shows that taking a specific supplement containing calcium 600 mg plus vitamin D 200 IU (Caltrate 600 D, Wyeth Consumer Healthcare Inc.) twice daily in combination with calorie restriction does not reduce total or LDL cholesterol levels when compared with placebo (15601).
• Lead toxicity. It is unclear if oral calcium is beneficial for reducing blood levels of lead. Details: Lead is mobilized along with calcium from bone during pregnancy and lactation, resulting in increased serum concentrations of lead. One clinical study suggests that calcium supplementation does not significantly decrease these elevated lead concentrations (1586). However, another clinical study suggests that taking calcium reduces blood lead levels by 11% when compared with placebo, with greatest effects observed in those with high baseline levels of lead (38957).
• Lyme disease. Although there is interest in using oral calcium for Lyme disease, there is insufficient reliable information about the clinical effects of calcium for this condition.
• Metabolic syndrome. It is unclear if oral calcium alone or with vitamin D is beneficial for metabolic syndrome prevention. Details: Population research has found that a higher intake of calcium from diet and supplements alone, or in combination with vitamin D, is associated with a lower risk of developing metabolic syndrome when compared with lower calcium intake (14265,16713).
• Nephrotic syndrome. It is unclear if oral calcium with vitamin D is beneficial for preventing nephrotic syndrome. Details: Clinical research shows that taking calcium 500-1000 mg daily for 3 months in combination with vitamin D3 60,000 IU daily or weekly for 4 weeks has no effect on bone mineral density or the risk of relapse in children with steroid-sensitive nephrotic syndrome (97355).
• Nonmelanoma skin cancer. It is unclear if oral calcium is beneficial for preventing keratinocyte carcinomas. Details: In middle aged and older adults recently diagnosed with a colorectal adenoma, clinical research shows that taking calcium 1200 mg daily as calcium carbonate for 3-5 years does not reduce the incidence of keratinocyte cancer when compared with placebo over a median of 8 years. A sub-group analysis shows that taking calcium alone or with vitamin D3 1000 IU daily reduced the risk of invasive cutaneous squamous cell carcinoma by a moderate amount, but had no effect on the risk of basal cell carcinoma (104622).
• Oral mucositis. When used in combination with fluoride treatments, a calcium phosphate mouth rinse seems to prevent and reduce mucositis-related pain in patients undergoing hematopoietic stem cell transplantation (HSCT). Details: A small clinical study in patients undergoing HSCT shows that using a particular mouth rinse (Caphosol, EUSA Pharma) containing calcium phosphate, in combination with fluoride treatments, reduces days of mucositis, the duration of pain, and the dose and days of morphine used when compared with placebo and fluoride treatment (38611).
• Ovarian cancer. It is unclear if oral calcium is beneficial for ovarian cancer prevention. Details: An older meta-analysis of 12 cohort studies found that dietary calcium intake is not associated with a reduced risk of ovarian cancer (38792). However, a more recent pooled analysis of 15 cohort and case-control studies has found that the highest intake of dietary or dairy calcium is associated with a 20% lower risk of ovarian cancer when compared to the lowest intake (97349).
• Postpartum depression. It is unclear if oral calcium is beneficial for reducing postpartum depression risk. Details: Preliminary clinical research shows that taking calcium 2 grams daily beginning at 11-21 weeks gestation reduces depression at 12 weeks postpartum when compared with placebo. However, no benefit is seen at 6 weeks postpartum (39447).
• Pregnancy-related leg cramps. It is unclear if oral calcium is beneficial for preventing leg cramps during pregnancy. Details: A small clinical study shows that taking calcium 1 gram twice daily (as a mixture of salts) for 2 weeks can reduce pregnancy-related leg cramps during the second half of pregnancy when compared with no treatment (2567).
• Prostate cancer. It is unclear if oral calcium is beneficial for prostate cancer prevention. Details: Some clinical research shows that taking calcium 1200 mg daily might decrease the risk of developing prostate cancer (14133). However, some epidemiological research suggests that consuming very high doses of calcium, over 2000 mg daily, might actually increase the risk of developing prostate cancer (14134). Some epidemiological research also suggests that doses greater than 1500 mg daily increase the risk of poorly differentiated, clinically advanced, and fatal prostate cancer (14132). Consumption of dairy products has also been weakly linked to a modest increase in risk of prostate cancer (98894). However, contradictory research suggests that there is no association between dietary intake of calcium and overall risk of prostate cancer (14131,14132,104630).
• Stroke. It is unclear if oral calcium is beneficial for stroke prevention. Details: Some population research has found that increasing dietary calcium intake is associated with a decreased risk of ischemic stroke (4822,38678). However, other population research has found that increasing dietary calcium intake is not associated with a decreased risk of stroke (91350). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years does not affect the risk of stroke when compared with control. However, the majority of the included research evaluated postmenopausal females, and it is unclear if this finding is applicable to other populations (107233).
• Vertigo. Oral calcium with vitamin D might reduce positional vertigo; the effect of calcium when used alone is unclear. Details: A large clinical study in adults with recurrent benign paroxysmal positional vertigo shows that taking calcium 500 mg and vitamin D 400 IU twice daily for one year reduces annual recurrence of vertigo by 27% when compared with no treatment. The number needed to treat to prevent vertigo was 3.7 (103681). It is unclear if this benefit is due to vitamin D, calcium, or the combination. More evidence is needed to rate calcium for these uses.

(Read more about CALCIUM)

POSSIBLY EFFECTIVE

• Schizophrenia. Oral glycine may improve negative, but not positive, symptoms of schizophrenia when used as adjunct to therapy with typical antipsychotics in patients resistant to monotherapy. However, glycine does not seem to provide additional benefit when used with clozapine. Details: Some small clinical trials show that taking glycine 0.4-0.8 grams/kg daily in divided doses along with conventional treatment seems to reduce negative symptoms of schizophrenia in patients that are resistant to monotherapy with typical antipsychotics such as thioridazine, haloperidol, and perphenazine (10250,10251,10252,98591). However, when used with the atypical antipsychotic clozapine, glycine appears to have a negligible effect on or worsen symptoms of schizophrenia (10253,11321). Additionally, glycine does not seem to improve positive symptoms of schizophrenia (10250,10251,10252,98591).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• 3-phosphoglycerate dehydrogenase (3-PGDH) deficiency. It is unclear if oral glycine is beneficial in patients with 3-PGDH deficiency. Details: A case series describing two patients with 3-PGDH deficiency who did not respond to serine supplementation suggests that taking oral glycine 0.2 grams/kg daily along with serine might reduce seizure frequency. 3-PGDH deficiency is a rare condition in which serine is not synthesized properly (10254).
• Aging. Oral glycine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in adults aged 61-80 years with overweight or obesity shows that taking a specific combination product (GlyNAC), providing glycine 100 mg/kg and N-acetyl cysteine 100 mg/kg, daily for 16 weeks improves some markers associated with aging, including glutathione levels, oxidative stress, mitochondrial impairment, genomic damage, inflammation, and endothelial dysfunction, when compared to baseline. Improvements in these measures were lacking in the placebo group (110624). The validity of these findings is limited by a lack of statistical comparison between groups. Also, it is unclear if these effects are due to glycine, N-acetyl cysteine, or the combination.
• Attention deficit-hyperactivity disorder (ADHD). Although there has been interest in using oral glycine for ADHD, there is insufficient reliable information about the clinical effects of glycine for this purpose.
• Benign prostatic hyperplasia (BPH). Although there has been interest in using oral glycine for BPH, there is insufficient reliable information about the clinical effects of glycine for this purpose.
• Cognitive function. Small clinical studies suggest that oral glycine may modestly improve memory and cognitive function in some patients. Details: Two small clinical studies in healthy young adults and adults with psychosis risk syndrome show that taking glycine 0.2-0.4 grams/kg once or twice daily for up to 24 weeks may improve some measures of memory and cognitive performance when compared with baseline or placebo (11322,92321).
• Cystic fibrosis. It is unclear if oral glycine is beneficial in patients with cystic fibrosis. Details: A small clinical trial in patients 6-23 years of age with cystic fibrosis shows that taking glycine 0.5 grams/kg daily for 8 weeks modestly improves some measures of lung function and reduces sputum and dyspnea by 15% and 23%, respectively, when compared with placebo. However, taking glycine does not improve appetite or energy (98583).
• Gout. Oral glycine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in patients with mild hyperuricemia shows that taking a powder containing glycine 3 grams and L-tryptophan 0.2 grams nightly at bedtime for 6 weeks reduces serum uric acid levels by 0.3 mg/dL when compared with placebo. Improvements also occurred in the subgroup of patients with uric acid levels greater than 7 mg/dL, the point at which symptoms of gout can occur (99883). However, it is unclear if this combination improves gout-related pain. Also, it is not clear if these findings are due to glycine, L-tryptophan, or the combination.
• Insomnia. Small clinical studies suggest that oral glycine may modestly improve sleep quality and daytime feelings of fatigue in patients with poor sleep quality or a restricted sleep duration. Details: Two very small studies in patients who have reported a subjective reduction in sleep quality show that taking glycine 3 grams one hour before bedtime for 2-4 days improves overall sleep quality and sleep efficacy when compared with placebo (92318,92320). Another very small clinical study in healthy males shows that taking glycine 3 grams 30 minutes before bedtime for 3 nights, during which time sleep duration is restricted by 25%, modestly reduces feelings of fatigue after the first night, but not after the third night, when compared with placebo (92316). The effects of glycine on sleep measures have also been evaluated in combination with other ingredients. A very small crossover study in healthy adults without documented sleep disorders shows that taking a combination product containing glycine 3000 mg, tryptophan 1000 mg, magnesium 300 mg, tart cherry powder 220 mg, and L-theanine 200 mg before bed for 3 nights reduces sleep onset latency, increases total sleep time, increases sleep efficiency, and reduces morning sleepiness when compared with placebo (111184). It is unclear if these effects are due to glycine, other ingredients, or the combination.
• Isovaleric acidemia. Although there has been interest in using oral glycine for isovaleric acidemia, there is insufficient reliable information about the clinical effects of glycine for this purpose.
• Metabolic syndrome. Although there has been interest in using oral glycine for metabolic syndrome, there is insufficient reliable information about the clinical effects of glycine for this purpose.
• Obesity. Oral glycine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in adults aged 61-80 years with overweight or obesity shows that taking a specific combination product (GlyNAC), providing glycine 100 mg/kg and N-acetyl cysteine 100 mg/kg, daily for 16 weeks reduces waist circumference but does not improve body weight or body mass index (BMI) when compared to baseline. None of these outcomes were improved in individuals taking placebo (110624). The validity of these findings is limited by a lack of statistical comparison between groups. Also, it is unclear if these effects are due to glycine, N-acetyl cysteine, or the combination.
• Overactive bladder. It is unclear if oral glycine is beneficial in patients with overactive bladder. Details: One very small, non-randomized, crossover trial in patients with overactive bladder shows that taking glycine 3 grams twice daily for 4 weeks reduces urinary urgency, urinary incontinence, and nighttime urinary frequency and improves quality of life scores when compared with placebo (106497). The validity of these findings is limited by a lack of randomization.
• Physical performance. Oral glycine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in adults aged 61-80 years with overweight or obesity shows that taking a specific combination product (GlyNAC), providing glycine 100 mg/kg and N-acetyl cysteine 100 mg/kg, daily for 16 weeks improves upper and lower extremity strength and gait speed, but not walking distance, when compared to baseline. None of these outcomes were improved in individuals taking placebo (110624). The validity of these findings is limited by a lack of statistical comparison between groups. Also, it is unclear if these effects are due to glycine, N-acetyl cysteine, or the combination.
• Stroke. It is unclear if sublingual glycine is beneficial in patients with acute ischemic stroke. Details: One small clinical study in patients with acute ischemic stroke in the carotid artery territory shows that taking glycine 1-2 grams sublingually daily for 5 days, starting within 6 hours after the onset of stroke, modestly improves clinical outcomes on the Orgogozo Stroke Scale, the Scandinavian Stroke Scale, and the Barthel index when compared with placebo (11320).
• Venous leg ulcers. Topical glycine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study shows that applying a cream containing glycine, L-cysteine, and DL-threonine to leg ulcers reduces pain and modestly improves healing when compared with a placebo cream (10255). It is unclear if these effects are due to glycine, other ingredients, or the combination.
• Wound healing. Although there has been interest in using topical glycine for wound healing, there is insufficient reliable information about the clinical effects of glycine for this purpose. More evidence is needed to rate glycine for these uses.

(Read more about GLYCINE)

POSSIBLY EFFECTIVE

• Atopic dermatitis (eczema). Some clinical research suggests that topical licorice seems to improve symptoms of atopic dermatitis. Details: Applying gel formulations containing 1% or 2% licorice root extract three times daily for 2 weeks seems to reduce erythema by 35% to 61%, edema by 57% to 84%, and itching by 44% to 73%. The 2% gel seems to be more effective than the 1% gel (59732).
• Canker sores. Some clinical research suggests that topical licorice patches and mouth rinses seems to reduce ulcer size and pain in patients with recurrent aphthous stomatitis. Details: Clinical research shows that applying an oral patch containing licorice 0.015-0.229 mg/kg for 16 hours each day for 8 days does not affect ulcer healing time, but reduces ulcer size and post-stimulus pain, when compared with placebo (59769). A small clinical study also shows that applying bioadhesive hydrogel patches containing 1% licorice extract reduces the pain, as well as the diameter of necrosis and inflammatory halo of recurrent canker sores, when compared to baseline (59781). Mouth rinses containing licorice have also been used. One clinical study shows that swishing a diphenhydramine and 5% licorice extract solution around the mouth for about 3 minutes four times daily until the sores have healed reduces the average time to healing by 1.5 days when compared to a solution containing diphenhydramine alone. Pain was reduced by up to 69% more in those using licorice extract (104564). Another small clinical study shows that gargling with licorice extract four times daily for 2 days has a large beneficial effect on pain and ulcer size when compared with using a placebo gargle. The licorice extract was made by boiling licorice root 40 grams in one liter of water for 30 minutes and cooled (110319). In addition, preliminary clinical research shows that gargling with warm water containing deglycyrrhizinated licorice powder 200 mg four times daily for 7 days improves pain in 75% of patients by day one and results in complete healing in 75% of patients by day three (59857).
• Endotracheal intubation-related adverse effects. Some clinical research suggests that using licorice as a gargle or lozenge prior to endotracheal intubation can reduce adverse effects like sore throat and cough. Details: A meta-analysis of 5 clinical trials in patients undergoing elective surgical procedures shows that topical use of licorice, either as a gargle or lozenge, prior to endotracheal intubation reduces the risk for sore throat by 56% and reduces the risk for cough by 39% when compared with a control group at 24 hours post-extubation (100985). One clinical study included in this analysis shows that sucking on a single lozenge (Sualin, Hamdard Pharma) containing licorice extract 97 mg beginning 30 minutes prior to intubation reduces the risk for cough immediately after extubation by 56% when compared with a sugar candy lozenge. However, it doesn't seem to reduce cough at 30 minutes, 12 hours, or 24 hours post-extubation. This lozenge also appears to reduce the risk for sore throat by about 32% at 12 and 24 hours post-extubation, but not immediately or 30 minutes after extubation (25670). Additional clinical studies included in the meta-analysis show that gargling with fluid prepared with licorice 0.5 grams for at least one minute beginning 5 minutes prior to endotracheal intubation reduces the incidence and severity of post-extubation sore throat and coughing when compared with a water control (26464,59793).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Topical licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in patients with mild to moderate acne associated with mask wearing shows that topical application of a combination of licorice root extract 0.3%, calendula 4%, and snail secretion filtrate 40% (AI complex) to the face twice daily for 12 weeks modestly reduces inflammatory, but not non-inflammatory or total, acne lesions when compared with placebo. There was no difference in overall treatment success, defined as at least almost clear skin or a large improvement (110322). It is unclear if any benefits are due to licorice, other ingredients, or the combination.
• Addison disease. Although there has been interest in using oral licorice for Addison disease, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Adrenal insufficiency. Although there has been interest in using oral licorice for adrenal insufficiency, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Allergic rhinitis (hay fever). It is unclear if using a licorice-containing nasal irrigation suspension improves symptoms in patients with allergic rhinitis. Details: A clinical study in patients with allergic rhinitis shows that using a nasal irrigation suspension containing licorice extract 900 mg daily for 1 month improves symptoms such as nasal blockage, rhinorrhea, sneezing, postnasal discharge, and olfactory disturbance when compared with baseline (108569). Although the study also utilized mometasone 2 mg nasal spray and isotonic saline nasal irrigation as comparators, symptom improvement was observed in all three groups, and there was no statistical comparison of outcomes between groups.
• Antipsychotic-induced hyperprolactinemia. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in females with risperidone-induced hyperprolactinemia shows that taking a combination of licorice and peony (Peony-Glycyrrhiza Decoction; PGD) 45 grams daily for 4 weeks reduces prolactin levels to a similar extent as bromocriptine (59775). However, another study shows that taking the same product at the same dose for 16 weeks has no effect on prolactin levels in females with antipsychotic-induced hyperprolactinemia when compared with placebo. Although the prolactin-related adverse event questionnaire total score was moderately improved, there was no effect on clinically meaningful symptoms or menstrual resumption (97219). Both studies show no effect on psychotic symptoms (59775,97219). Preliminary clinical research in male patients with antipsychotic-induced hyperprolactinemia shows that taking an herbal extract containing licorice and peony (shakuyaku-kanzo-to) 2.5 grams three times daily reduces prolactin levels after 4 weeks, but does not have a significant effect on prolactin levels 4 weeks after treatment cessation (59907).
• Bleeding. Topical licorice might reduce bleeding when used in combination with other ingredients; its effect when used alone is unclear. Details: Some preliminary clinical research shows that topically applying 4 mL of a specific product (Ankaferd Blood Stopper, Mefar Ilaç Sanayi A.S.) containing licorice, Alpinia, thyme, stinging nettle, and common grape vine reduces bleeding, but does not improve the surgical time for episiotomy repair, when compared with saline (31010). Other preliminary clinical research shows that ampules of this same product placed in empty alveolus for up to 20 minutes reduces bleeding in postsurgical dental patients with increased bleeding tendency (31002).
• Cancer-related pain. It is unclear if oral licorice is beneficial for pain in patients with cancer. Details: Preliminary clinical research shows that taking a 1:1 combination of licorice root and peony root, along with a Taiwanese tonic vegetable soup comprised of lily bulb, lotus seed, and jujube fruit, reduces pain levels in terminal cancer patients when compared with patients consuming only the soup or the regular hospital diet (59770).
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral licorice for CFS, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Colic. Although there has been interest in using oral licorice for colic, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Coronavirus disease 2019 (COVID-19). Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients hospitalized in Egypt with moderate COVID-19 shows that administering oral licorice extract 300 mg (standardized to contain glycyrrhizin 60 mg) once daily and Boswellia serrata extract 300 mg twice daily for 14 days, along with following an institution-based COVID-19 treatment protocol, may modestly improve mortality and time to recovery when compared with patients receiving the standard protocol alone. The standard treatment protocol included acetaminophen, azithromycin, vitamin C, zinc, and enoxaparin (108579). It is unclear if any effect is due to licorice, Boswellia serrata, or the combination.
• Dental caries. It is unclear if oral licorice is beneficial for the prevention of dental caries. Details: One clinical study in adults shows that swishing 15 mL of a solution containing licorice extract 1% once nightly before bed for 5 days may reduce the acid production of cavity-causing bacteria, which may modestly reduce cavity risk, when compared with using a saline solution (108567). The validity of this study is limited by the short duration of treatment and follow-up.
• Dental plaque. It is unclear if licorice toothpaste or mouthwash is beneficial for reducing plaque. Details: Preliminary clinical research shows that using 0.25% or 0.50% glycyrrhizin-containing toothpaste twice daily does not reduce the amount of plaque, gingivitis, or bleeding in patients with proper dental hygienic measures when compared with the same toothpaste without glycyrrhizin (59812). Also, other preliminary clinical research shows that using glycyrrhizin-containing mouthwash for 3 days does not significantly reduce plaque levels (59855).
• Depression. It is unclear if adding oral licorice to standard treatment is beneficial for improving depression. Details: A very small, nonblinded clinical study in hospitalized adults with major depressive disorder shows that adding licorice extract 1400 mg daily, standardized to glycyrrhizin 7% to 8%, to standard treatment for 2 weeks improves depression rating scores when compared with baseline, although these improvements were numerically similar to those seen with standard treatment alone. Patients in the treatment group also took oral magnesium citrate 300 mg daily to prevent magnesium depletion. The validity of this finding is limited due to the small size of the study, short duration of treatment, and unclear reporting (108575).
• Diabetes. Although there has been interest in using oral licorice for diabetes, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Dry mouth. It is unclear if rinsing the mouth with licorice is beneficial for dry mouth in people on hemodialysis. Details: Preliminary clinical research in hemodialysis patients with dry mouth shows that rinsing with a licorice mouthwash containing 8.34 grams of licorice concentrate per 500 mL of water with every meal for 10 days does not affect salivary flow rate, but reduces subjective feelings of dry mouth by about 28%, when compared with a water-based mouthwash and control group (97220).
• Dysmenorrhea. It is unclear if oral licorice is beneficial for reducing pain. Details: Preliminary clinical research shows that taking a syrup providing licorice extract 750 mg twice daily for the first 5 days of the menstrual cycle reduces pain as effectively as ibuprofen 400 mg every 8 hours in patients with moderate or severe dysmenorrhea (104558).
• Dyspepsia. Oral licorice might improve symptoms of dyspepsia when used in combination with other ingredients; its effect when used alone is unclear. Details: Various combination products manufactured by Steigerwald Arzneimittelwerk GmbH have been evaluated for dyspepsia. Two specific combination products containing licorice root (Iberogast; STW-5-S) seem to improve symptoms of dyspepsia. The combinations include licorice plus milk thistle, peppermint leaf, German chamomile, caraway, celandine, angelica, and lemon balm either with (Iberogast) or without clown's mustard plant (STW-5-S) 1 mL three times daily for 4 weeks (19532). A meta-analysis of studies using the Iberogast product shows that taking 1 mL orally three times daily over a period of 4 weeks reduces severity of acid reflux, epigastric pain, cramping, nausea, and vomiting when compared with placebo (13089). Also, using a preparation containing clown's mustard plant, German chamomile, peppermint, caraway, licorice, and lemon balm (STW 5-II) 1 mL three times daily for up to 12 weeks improves dyspepsia symptoms in 40% more patients when compared with placebo (12724).
• Familial Mediterranean fever. It is unclear if oral licorice is beneficial for familial Mediterranean fever. Details: Preliminary clinical research shows that taking a combination of licorice, andrographis, Siberian ginseng, and schisandra (ImmunoGuard, Inspired Nutritionals) four tablets three times daily for one month reduces the duration, frequency, and severity of attacks of familial Mediterranean fever in children when compared with placebo (12382). It is unclear if these effects are due to licorice, other ingredients, or the combination.
• Helicobacter pylori. It is unclear if oral licorice is beneficial for Helicobacter pylori eradication. Details: Some preliminary clinical research shows that adding licorice (D-Reglis, Iran Darouk Pharmaceutical Co.) 380 mg twice daily to conventional clarithromycin-based triple therapy for 14 days improves eradication rate by an additional 21% when compared with conventional treatment alone. However, any additional benefit might be limited to patients with peptic ulcer disease (97221). Other preliminary clinical research shows that taking a combination of licorice extract 100 mg and Lactobacillus paracasei HP7 in 150 mL of fermented milk daily for 8 weeks does not increase eradication rates when compared with fermented milk alone, although it may improve gastrointestinal symptom scores, decrease the gastric load of Helicobacter pylori, and improve some measures of inflammation when compared to baseline (100984).
• Hepatitis. Evidence for the use of intravenous licorice in the management of hepatitis B and C is mixed. Details: In some preliminary clinical research, a specific glycyrrhizin-containing intravenous preparation (Stronger Neominophagen C, Minophagen Pharmaceutical Co. Ltd.) appears to reduce mortality due to viral hepatitis by about 50% (3250). Other clinical research suggests that this same product reduces serum alanine aminotransferase (ALT) in hepatitis C patients but does not improve hepatitis C virus (HCV)-RNA levels (3247,59712,59721,59920). When used long-term, this preparation seems to reduce the risk of hepatocellular carcinoma in hepatitis C patients when compared to long-term use of other supplements, such as vitamin K (59905). This product has been used in various doses: 40 or 100 mL, containing 2 mg glycyrrhizin, 1 mg cysteine, and 20 mg of glycine per mL of solution, administered daily for 4-8 weeks, followed by 40 or 100 mL 2-7 times weekly for 2-16 weeks, has been used (3250,59905,59915); 40-120 mL diluted in 100 mL of 5% glucose solution and administered three times weekly for 4 weeks (59712,59721); 100 mL, which contained 200 mg glycyrrhizin, administered undiluted six times weekly for 4 weeks (59721); or 60 mL administered three times weekly for 16 weeks (59920). Other research shows that this preparation reduces ALT, aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT) in patients with hepatitis B virus (59915). Oral licorice has not been evaluated for this purpose.
• Hypercholesterolemia. It is unclear if oral licorice is beneficial for improving cholesterol. Details: Preliminary clinical research shows that taking licorice root extract 0.1 grams daily for one month reduces plasma total cholesterol levels by 5%, plasma low-density lipoprotein (LDL) cholesterol levels by 9%, and plasma triglyceride levels by 14% when compared with baseline in patients with moderate hypercholesterolemia (59725). The validity of these findings is limited by the lack of a comparator group.
• Hyperkalemia. It is unclear if oral licorice is beneficial for reducing potassium levels. Details: Some clinical research in adults with diabetes and hypoaldosteronism suggests that taking glycyrrhizin 150 mg daily decreases potassium levels when compared with calcium polystyrene sulfonate (59897). Also, one very small clinical study in patients with anuria shows that taking glycyrrhetinic acid 1 gram daily for 2 weeks seems to decrease plasma potassium, but does not improve blood pressure, when compared with placebo (59723).
• IgA vasculitis. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small retrospective study in patients aged 5-36 years with newly diagnosed IgA vasculitis shows that taking compound glycyrrhizin (Eisai Pharmaceutical Co, Ltd) three times daily along with loratadine, calcium, vitamin C, rutin, and other unspecified conventional treatments is associated with an improvement in cutaneous purpura symptoms and time to symptom regression when compared with placebo. After 1 month, the rate of complete resolution and time to regression in the treatment group was 82% and 5 days, respectively, compared with 65% and 8 days, respectively, in the placebo group. Compound glycyrrhizin contained glycyrrhizin, glycine, and methionine and was dosed by age, with a dose of 25 mg daily in those 12 years or younger and 50 mg daily in those over 12 years (108580).
• Irritable bowel syndrome (IBS). Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that a formulation containing licorice root, slippery elm bark, lactulose, and oat bran daily for 2 weeks improves stool consistency and increases bowel movement frequency by 20% in individuals with constipation-predominant IBS when compared to baseline. Symptoms of abdominal pain, bloating, straining, and global severity might also be reduced (35462). The validity of these findings is limited by the lack of a comparator group. Additionally, it is unclear if any benefits are due to licorice, other ingredients, or the combination.
• Lichen planus. It is unclear if intravenous licorice is beneficial for lichen planus. Details: A very small clinical study shows that intravenous administration of 0.2% glycyrrhizin solution, 40 mL daily for 4 weeks, improves clinical symptoms of oral lichen planus in a greater percentage of patients with chronic hepatitis C when compared with dental cleaning (59903). There is no evidence suggesting that oral licorice is beneficial.
• Liver cancer. Although there has been interest in using oral or intravenous licorice preparations for liver cancer, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Melasma. Topical licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a topical cream (Clariderm Clear, Stiefel Laboratories Inc.) containing 7% licorice, emblica, and belides twice daily for 60 days is as effective as a cream containing 2% hydroquinone for lightening the skin in patients with melasma (59824). It is unclear if this effect is due to licorice, other ingredients, or the combination.
• Menopausal symptoms. It is unclear if oral licorice is beneficial for reducing hot flash frequency or severity. Details: In one preliminary clinical study, taking licorice root extract 330 mg orally three times daily for 8 weeks modestly reduces the frequency of hot flashes by about 1.3 per day and the severity of hot flashes by about 40% when compared with placebo (94659). However, another preliminary clinical study shows that taking a specific licorice root extract (D-Reglis, Iran Darouk Pharmaceutical Co.) 650 mg orally daily for 90 days does not reduce the number or severity of hot flashes when compared to baseline (25694).
• Muscle cramps. It is unclear if oral licorice is beneficial for muscle cramps due to cirrhosis or hemodialysis. Details: Preliminary clinical research shows that taking a specific combination of licorice and peony (shakuyaku-kanzo-to) might reduce muscle cramps in patients with hepatic cirrhosis or in patients undergoing hemodialysis when compared to baseline (13550,13551,13552). This combination was taken as 6-7.5 grams daily in up to three divided doses for 2-4 weeks in two studies (13550,13552). In a third study, the combination was taken as 2.5 grams during hemodialysis with self-administration at the onset of muscle cramping (13551).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral licorice is beneficial for NAFLD. Details: A small clinical trial in females with NAFLD shows that taking licorice extract (Shirin Darou Company, Shiraz, Iran) 500 mg twice daily for 12 weeks improves some measures of liver health and glycemic control when compared with placebo. Modest improvements occurred in levels of alanine aminotransferase, as well as in measures of insulin resistance and severity of liver steatosis based on ultrasonographic evaluation. There were no effects on body mass index (BMI), plasma lipids, fasting blood glucose, or other liver enzymes. All patients were also given weight loss and healthy lifestyle advice (110320). Preliminary clinical research shows that taking licorice root extract 2 grams daily for 2 months reduces liver function enzyme levels in patients with NAFLD when compared to pre-treatment (59841). It is unclear if this reduction is clinically significant.
• Obesity. It is unclear if oral licorice is beneficial for weight loss. Details: Preliminary clinical research shows that taking a specific licorice flavonoid oil (Glavonoid) 300 mg daily for 8 weeks has no effect on weight or body fat when compared with placebo in obese patients (17727).
• Oral mucositis. It is unclear if oral or topical licorice is beneficial for the prevention or treatment of chemotherapy- or radiation-induced oral mucositis. Details: In patients with head and neck cancer undergoing chemoradiation, preliminary clinical research shows that using oral and topical licorice powder twice daily in addition to conventional treatments for 6 weeks reduces the overall incidence of mucositis and also reduces the risk of developing severe oral mucositis to 15.5%, compared with 20% in those using topical honey and 43% in those using conventional treatments alone. Licorice treatment consisted of yastimadhu powder 5 grams mixed in honey for topical application in the mouth, as well as yastimadhu capsule 500 mg twice daily orally (104562). A small clinical trial in patients with head and neck cancer and oral mucositis currently undergoing radiation therapy shows that applying a mucoadhesive film containing licorice to the upper lip mucosal surface four times daily for 4 weeks, in conjunction with standard oral care, improves pain scores, mucositis grading, and ulcer size when compared with placebo film (108572). The validity of this finding is limited due to the short duration of treatment and exclusion of patients with severe mucositis.
• Osteoarthritis. Although there has been interest in using oral licorice for osteoarthritis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Osteoporosis. Although there has been interest in using oral licorice for osteoporosis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Parkinson disease. It is unclear if oral licorice is beneficial for improving Parkinson disease symptoms. Details: A small clinical study in patients with Parkinson disease shows that taking licorice extract 136 mg (containing glycyrrhizin 12.14 mg, polyphenols 136 mcg, and flavonoids 2.6 mcg) in a 5 mL syrup twice daily for 6 months improves Parkinson symptoms, tremor, and overall daily activities when compared with placebo (102961).
• Peptic ulcers. Evidence for the use of oral licorice for peptic ulcers is mixed. Details: There is some evidence that taking 6-12 tablets each containing deglycyrrhizinated licorice 380 mg, bismuth subnitrate 100 mg, aluminum hydroxide gel 100 mg, magnesium carbonate 200 mg, sodium bicarbonate 100 mg, and powdered alder buckthorn bark 30 mg (Caved-S, Cedona) in up to three divided doses daily for 4-16 weeks might accelerate the healing of peptic ulcers (11312,11313). Some clinical research also shows that this product is as effective as carbenoxolone sodium (Biogastrone) when taken at doses of two tablets three times daily after meals for 4 weeks (59871). In contrast, taking deglycyrrhizinated licorice (Ulcedal, Cedona, and others) 450-1000 mg three to five times daily for 4-8 weeks or glycyrrhizinic acid-reduced licorice 760 mg three times daily for 6 weeks does not seem to reduce the need for medication, pain, burning, or other discomfort in patients with peptic ulcers when compared with placebo (59864,59865,59873,59874).
• Physical performance. It is unclear if oral licorice is beneficial for improving physical performance in older females. Details: A small clinical trial in healthy females 59 years and older shows that taking licorice flavonoid oil 300 mg orally daily for 16 weeks in addition to strength training does not improve walking speed or other measures of functional mobility when compared with strength training alone (102960).
• Polycystic ovary syndrome (PCOS). Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking licorice root extract 2250 mg daily along with Ceylon cinnamon, levant berry, St. John's Wort, peony, and tribulus for 3 months with lifestyle modification improves symptoms of PCOS, including a reduction in oligomenorrhea/amenorrhea by 33% and the number of days between menstrual cycles by 43 days when compared with lifestyle modification alone. Although conception rate increased 4-fold in the intervention group, live birth rate was similar between groups (97216). The effect of licorice alone for the treatment of PCOS is unknown.
• Prostate cancer. Although there has been interest in using oral licorice for prostate cancer, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Psoriasis. It is unclear if topical licorice is beneficial for improving psoriasis symptoms. Details: Preliminary clinical research shows that using a topical cream containing licorice extract and milk proteins twice daily for 4 weeks does not reduce the duration of corticosteroid cream therapy in patients with palmar and/or plantar psoriasis, but may improve skin peeling, the area of skin affected, and some subjective symptoms, when compared with corticosteroid cream alone (59823).
• Systemic lupus erythematosus (SLE). Although there has been interest in using oral licorice for SLE, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Tuberculosis. Although there has been interest in using oral licorice for tuberculosis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Urticaria. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of clinical research in adults with chronic urticaria shows that taking compound glycyrrhizin, containing glycyrrhizin, N-acetyl cysteine, and glycine, as 50-75 mg three times daily along with desloratadine 5-8.8 mg daily for 4 weeks improves response rate, cure rate, and recurrence rate when compared with desloratadine alone (108571). However, most studies included in the meta-analysis were low quality, and all studies were conducted in China. Higher quality studies in other geographic locations are needed to confirm these findings.
• Vitiligo. It is unclear if the licorice constituent compound glycyrrhizin is beneficial for vitiligo. Details: A meta-analysis of 14 clinical studies in patients aged 3-68 years old with vitiligo shows that taking licorice constituent compound glycyrrhizin 25-75 mg 3 times daily for 2-6 months with standard treatment improves effectiveness, cure rate, and immune-mediated inflammatory markers when compared with standard treatment alone (112232). More evidence is needed to rate licorice for these uses.

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LIKELY SAFE ...when used orally or intravenously and appropriately. Calcium is safe when used in appropriate doses (7555,12928,12946,95817). However, excessive doses should be avoided. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: Age 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg; 19-50 years, 2500 mg; 51+ years, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stone, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients not to consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

POSSIBLY UNSAFE ...when used orally in excessive doses. The National Academy of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 19-50 years, 2500 mg; 51 years and older, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients to not consume more than the recommended daily intake of 1000-1200 mg per day and to consider total calcium intake from both dietary and supplemental sources (17484). Also, advise patients taking calcium supplements to take calcium along with vitamin D (93533).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Calcium is safe when used in appropriate doses (17506).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (945,1586,3263,3264,17506). The World Health Organization (WHO) recommends prescribing oral calcium supplementation 1.5-2 grams daily during pregnancy to those with low dietary calcium intake to prevent pre-eclampsia (97347).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the same daily tolerable upper intake level (UL) for calcium according to age independent of pregnancy status: 9-18 years, 3000 mg; 19-50 years, 2500 mg (17506). Doses over these amounts might increase the risk of neonatal hypocalcemia-induced seizures possibly caused by transient neonatal hypoparathyroidism in the setting of excessive calcium supplementation during pregnancy, especially during the third trimester. Neonatal hypocalcemia is a risk factor for neonatal seizures (97345).

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POSSIBLY SAFE ...when used orally and appropriately. Glycine has been used safely at doses up to 6 grams daily for 4 weeks (106497) and doses up to 9 grams daily for 3 days (10250,10251,10252,92319). There is insufficient reliable information available about the safety of glycine when used topically.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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LIKELY SAFE ...when used orally in amounts commonly found in foods. Licorice has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes. Licorice flavonoid oil 300 mg daily for 16 weeks, and deglycyrrhizinated licorice products in doses of up to 4.5 grams daily for up to 16 weeks, have been used with apparent safety (6196,11312,11313,17727,100984,102960). ...when licorice products containing glycyrrhizin are used orally in low doses, short-term. Licorice extract 272 mg, containing glycyrrhizin 24.3 mg, has been used daily with apparent safety for 6 months (102961). A licorice extract 1000 mg, containing monoammonium glycyrrhizinate 240 mg, has been used daily with apparent safety for 12 weeks (110320). In addition, a syrup providing licorice extract 750 mg has been used twice daily with apparent safety for 5 days (104558). ...when applied topically. A gel containing 2% licorice root extract has been applied to the skin with apparent safety for up to 2 weeks. (59732). A mouth rinse containing 5% licorice extract has been used with apparent safety four times daily for up to one week (104564).

POSSIBLY UNSAFE ...when licorice products containing glycyrrhizin are used orally in large amounts for several weeks, or in smaller amounts for longer periods of time. The European Scientific Committee on Food recommends that a safe average daily intake of glycyrrhizin should not exceed 10 mg (108577). In otherwise healthy people, consuming glycyrrhizin daily for several weeks or longer can cause severe adverse effects including pseudohyperaldosteronism, hypertensive crisis, hypokalemia, cardiac arrhythmias, and cardiac arrest. Doses of 20 grams or more of licorice products, containing at least 400 mg glycyrrhizin, are more likely to cause these effects; however, smaller amounts have also caused hypokalemia and associated symptoms when taken for months to years (781,3252,15590,15592,15594,15596,15597,15599,15600,16058)(59731,59740,59752,59785,59786,59787,59792,59795,59805,59811)(59816,59818,59820,59822,59826,59828,59849,59850,59851,59867)(59882,59885,59888,59889,59895,59900,59906,97213,110305). In patients with hypertension, cardiovascular or kidney conditions, or a high salt intake, as little as 5 grams of licorice product or 100 mg glycyrrhizin daily can cause severe adverse effects (15589,15593,15598,15600,59726).

PREGNANCY: UNSAFE
when used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week), during pregnancy seems to increase the risk of delivery before gestational age of 38 weeks (7619,10618). Furthermore, high intake of glycyrrhizin, at least 500 mg per week, during pregnancy is associated with increased salivary cortisol levels in the child by the age of 8 years. This suggests that high intake of licorice during pregnancy may increase hypothalamic-pituitary-adrenocortical axis activity in the child (26434); avoid using.

LACTATION:
Insufficient reliable information available; avoid using.

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ALUMINUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.  Details Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease (21631). However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption (93006).

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium reduces the absorption of bisphosphonates.  Details Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates (12937).

CALCIPOTRIENE (Dovonex) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Taking calcipotriene with calcium might increase the risk for hypercalcemia.  Details Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia (12938). Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

CALCIUM CHANNEL BLOCKERS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.  Details Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects (6124). But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers (12939,12947).

CEFTRIAXONE (Rocephin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.  Details Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction (15794,21632). So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.  Details Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin (12940). However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin (38960).

DILTIAZEM (Cardizem, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of diltiazem.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

DOLUTEGRAVIR (Tivicay) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of dolutegravir.  Details Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation (93578).

ELVITEGRAVIR (Vitekta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of elvitegravir.  Details Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation (94166).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption and effectiveness of levothyroxine.  Details Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes (5082). Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism (5081,5082,6137).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.  Details Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients (38953). Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption of quinolone antibiotics.  Details Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut (4412,10339,21638,38570).

RALTEGRAVIR (Isentress) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Calcium may reduce levels of raltegravir.  Details Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir (94164). However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure (94165).

SOTALOL (Betapace) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium seems to reduce the absorption of sotalol.  Details Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes (10018).

TETRACYCLINE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium seems to reduce the absorption of tetracycline antibiotics.  Details Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut (1843).

THIAZIDE DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.  Details Thiazides reduce calcium excretion by the kidneys (1902). Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of verapamil.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

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CLOZAPINE (Clozaril) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, glycine might decrease the effectiveness of clozapine.  Details One small clinical study in patients with schizophrenia shows that adding glycine to clozapine therapy worsens symptoms of schizophrenia when compared with clozapine alone (10253). The mechanism of this interaction is unclear.

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ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might reduce the effects of antihypertensive drugs.  Details In human research, licorice increases blood pressure in a dose-dependent manner (1372,7620,59877).

CISPLATIN (Platinol-AQ) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might reduce the effects of cisplatin.  Details In animal research, licorice diminished the therapeutic efficacy of cisplatin (59763).

CORTICOSTEROIDS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice and corticosteroids might increase the side effects of corticosteroids.  Details Case reports suggest that concomitant use of licorice and oral corticosteroids, such as hydrocortisone, can potentiate the duration of activity and increase blood levels of corticosteroids (3252,12672,20040,20042,48429,59756). Additionally, in one case report, a patient with neurogenic orthostatic hypertension stabilized on fludrocortisone 0.1 mg twice daily developed pseudohyperaldosteronism after recent consumption of large amounts of black licorice (108568).

CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2B6.  Details In vitro research shows that licorice extract and glabridin, a licorice constituent, inhibit CYP2B6 isoenzymes (10300,94822). Licorice extract from the species G. uralensis seems to inhibit CYP2B6 isoenzymes to a greater degree than G. glabra extract in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2B6; however, these interactions have not yet been reported in humans.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2C19.  Details In vitro, licorice extracts from the species G. glabra and G. uralensis inhibit CYP2C19 isoenzymes in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C19; however, this interaction has not yet been reported in humans.

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2C8.  Details In vitro, licorice extract from the species G. glabra and G. uralensis inhibits CYP2C8 isoenzymes (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C8; however, this interaction has not yet been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP2C9.  Details There is conflicting evidence about the effect of licorice on CYP2C9 enzyme activity. In vitro research shows that extracts from the licorice species G. glabra and G. uralensis moderately inhibit CYP2C9 isoenzymes (10300,94822). However, evidence from an animal model shows that licorice extract from the species G. uralensis can induce hepatic CYP2C9 activity (14441). Until more is known, licorice should be used cautiously in people taking CYP2C9 substrates.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP3A4.  Details Pharmacokinetic research shows that the licorice constituent glycyrrhizin, taken in a dosage of 150 mg orally twice daily for 14 days, modestly decreases the area under the concentration-time curve of midazolam by about 20%. Midazolam is a substrate of CYP3A4, suggesting that glycyrrhizin modestly induces CYP3A4 activity (59808). Animal research also shows that licorice extract from the species G. uralensis induces CYP3A4 activity (14441). However, licorice extract from G. glabra species appear to inhibit CYP3A4-induced metabolism of testosterone in vitro. It is thought that the G. glabra inhibits CYP3A4 due to its constituent glabridin, which is a moderate CYP3A4 inhibitor in vitro and not present in other licorice species (10300,94822). Until more is known, licorice should be used cautiously in people taking CYP3A4 substrates.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice with digoxin might increase the risk of cardiac toxicity.  Details Overuse or misuse of licorice with cardiac glycoside therapy might increase the risk of cardiac toxicity due to potassium loss (10393).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice with diuretic drugs might increase the risk of hypokalemia.  Details Overuse of licorice might compound diuretic-induced potassium loss (10393,20045,20046,59812). In one case report, a 72-year-old male with a past medical history of hypertension, type 2 diabetes, hyperlipidemia, arrhythmia, stroke, and hepatic dysfunction was hospitalized with severe hypokalemia and uncontrolled hypertension due to pseudohyperaldosteronism. This was thought to be provoked by concomitant daily consumption of a product containing 225 mg of glycyrrhizin, a constituent of licorice, and hydrochlorothiazide 12.5 mg for 1 month (108577).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase or decrease the effects of estrogen therapy.  Details Theoretically, licorice might interfere with estrogen therapy due to estrogenic and anti-estrogenic effects (7860,16058).

LOOP DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, loop diuretics might increase the mineralocorticoid effects of licorice.  Details Theoretically, loop diuretics might enhance the mineralocorticoid effects of licorice by inhibiting the enzyme that converts cortisol to cortisone; however, bumetanide (Bumex) does not appear to have this effect (3255).

METHOTREXATE (Trexall, others) Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, licorice might increase levels of methotrexate.  Details Animal research suggests that intravenous administration of glycyrrhizin, a licorice constituent, and high-dose methotrexate may delay methotrexate excretion and increase systemic exposure, leading to transient elevations in liver enzymes and total bilirubin (108570). This interaction has not yet been reported in humans.

MIDAZOLAM (Versed) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might decrease levels of midazolam.  Details In humans, the licorice constituent glycyrrhizin appears to moderately induce the metabolism of midazolam (59808). This is likely due to induction of cytochrome P450 3A4 by licorice. Until more is known, licorice should be used cautiously in people taking midazolam.

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease the absorption of P-glycoprotein substrates.  Details In vitro research shows that licorice can increase P-glycoprotein activity (104561).

PACLITAXEL (Abraxane, Onxol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease plasma levels and clinical effects of paclitaxel.  Details Multiple doses of licorice taken concomitantly with paclitaxel might reduce the effectiveness of paclitaxel. Animal research shows that licorice 3 grams/kg given orally for 14 days before intravenous administration of paclitaxel decreases the exposure to paclitaxel and increases its clearance. Theoretically, this occurs because licorice induces cytochrome P450 3A4 enzymes, which metabolize paclitaxel. Notably, a single dose of licorice did not affect exposure or clearance of paclitaxel (102959).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease plasma levels and clinical effects of warfarin.  Details Licorice seems to increase metabolism and decrease levels of warfarin in animal models. This is likely due to induction of cytochrome P450 2C9 (CYP2C9) metabolism by licorice (14441). Advise patients taking warfarin to avoid taking licorice.

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General ...Orally and intravenously, calcium is well-tolerated when used appropriately.
Most Common Adverse Effects:
Orally: Belching, constipation, diarrhea, flatulence, and stomach upset.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about calciphylaxis and kidney stones.

Cardiovascular ...There has been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these results, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of CVD, CHD, or MI (93533,107231). Also, the association between calcium supplementation and CVD, CHD, or MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482). To minimize the possible risk of CVD, CHD, or MI, advise patients not to consume more than the recommended daily intake of 1000-1200 mg and to consider total calcium intake from both dietary and supplemental sources (17484). While dietary intake of calcium is preferred over supplemental intake, advise patients who require calcium supplements to take calcium along with vitamin D, as this combination does not appear to be associated with an increased risk of MI (93533).
Rarely, calcium intake can increase the risk of calciphylaxis, which usually occurs in patients with kidney failure. Calciphylaxis is the deposition of calcium phosphate in arterioles, which causes skin ulcers and skin necrosis. In a case report, a 64-year-old female with a history of neck fracture, sepsis, and ischemic colitis presented with painful leg ulcers due to calciphylaxis. She discontinued calcium and vitamin D supplementation and was treated with sodium thiosulfate and supportive care (95816).

Gastrointestinal ...Orally, calcium can cause belching, flatulence, nausea, gastrointestinal discomfort, and diarrhea (1824,1843,12950,38803). Although constipation is frequently cited as an adverse effect of calcium, there is no scientific substantiation of this side effect (1824,1843,1844,1845,12950,38978). Calcium carbonate has been reported to cause acid rebound, but this is controversial (12935,12936).

Oncologic ...There is some concern that very high doses of calcium might increase the risk of prostate cancer. Some epidemiological evidence suggests that consuming over 2000 mg/day of dietary calcium might increase the risk for prostate cancer (4825,12949). Additional research suggests that calcium intake over 1500 mg/day might increase the risk of advanced prostate cancer and prostate cancer mortality (14132). Consumption of dairy products has also been weakly linked to a small increase in prostate cancer risk (98894). However, contradictory research suggests no association between dietary intake of calcium and overall prostate cancer risk (14131,14132,104630). More evidence is needed to determine the effect of calcium, if any, on prostate cancer risk.

Renal ...Kidney stones have been reported in individuals taking calcium carbonate 1500 mg daily in combination with vitamin D 2000 IU daily for 4 years (93943).

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General ...Orally and topically, glycine seems to be well tolerated.

Gastrointestinal ...Soft stools, nausea, vomiting, and upper gastrointestinal (GI) tract discomfort have occurred rarely with oral use of glycine. These symptoms resolve rapidly with discontinuation of glycine (10252,11320,92319). Dry mouth has also been reported but any association to glycine is unclear (92321).

Neurologic/CNS ...Mild sedation has occurred rarely with oral use of glycine. Symptoms resolve rapidly with discontinuation of glycine (10252,11320,92321). Irritability, insomnia, fatigue, memory impairment, headache, and sensory impairment have been reported, but any association with glycine is unclear (92321).

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General ...Orally, licorice is generally well tolerated when used in amounts commonly found in foods. It seems to be well tolerated when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes or when used topically, short-term.
Most Common Adverse Effects:
Orally: Headache, nausea, and vomiting.
Topically: Contact dermatitis.
Intravenously: Diarrhea, itching, nausea, and rash.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about acute renal failure, cardiac arrest, cardiac arrhythmias, hypertension, hypokalemia, muscle weakness, paralysis, pseudohyperaldosteronism, and seizure associated with long-term use or large amounts of licorice containing glycyrrhizin.

Cardiovascular ...Orally, excessive licorice ingestion can lead to pseudohyperaldosteronism, which can precipitate cardiovascular complications such as hypertension and hypertensive crisis, ventricular fibrillation or tachycardia, sinus pause, and cardiac arrest. These effects are due to the licorice constituent glycyrrhizin and usually occur when 20-30 grams or more of licorice product is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,97213) (104563,108574,108576,110305,112234). In one case report, an 89-year-old female taking an herbal medicine containing licorice experienced a fatal arrhythmia secondary to licorice-induced hypokalemia. The patient presented to the hospital with recurrent syncope, weakness, and fatigue for 5 days after taking an herbal medicine containing licorice for 2 months. Upon admission to the hospital, the patient developed seizures, QT prolongation, and ventricular arrhythmia requiring multiple defibrillations. Laboratory tests confirmed hypokalemia and pseudohyperaldosteronism (112234).
However, people with cardiovascular or kidney conditions may be more sensitive, so these adverse events may occur with doses as low as 5 grams of licorice product or glycyrrhizin 100 mg daily (15589,15593,15598,15600,59726). A case report in a 54-year-old male suggests that malnutrition might increase the risk of severe adverse effects with excessive licorice consumption. This patient presented to the emergency room with cardiac arrest and ventricular fibrillation after excessive daily consumption of licorice for about 3 weeks. This caused pseudohyperaldosteronism and then hypokalemia, leading to cardiovascular manifestations. In spite of resuscitative treatment, the patient progressed to kidney failure, refused dialysis, and died shortly thereafter (103791).

Dermatologic ...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912). There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578). Burning sensation, itching, redness, and scaling were reported rarely in patients applying a combination of licorice, calendula, and snail secretion filtrate to the face. The specific role of licorice is unclear (110322).
In rare cases, the glycyrrhizin constituent of licorice has caused rash and itching when administered intravenously (59712).

Endocrine ...Orally, excessive licorice ingestion can cause a syndrome of apparent mineralocorticoid excess, or pseudohyperaldosteronism, with sodium and water retention, increased urinary potassium loss, hypokalemia, and metabolic alkalosis due to its glycyrrhizin content (781,10619,15591,15592,15593,15594,15595,15596,15597,15598)(15600,16057,16835,25659,25660,25673,25719,26439,59818,59822)(59832,59864,91722,104563,108568,108574,110305,112234). These metabolic abnormalities can lead to hypertension, edema, EKG changes, fatigue, syncope, arrhythmias, cardiac arrest, headache, lethargy, muscle weakness, dropped head syndrome (DHS), rhabdomyolysis, myoglobinuria, paralysis, encephalopathy, respiratory impairment, hyperparathyroidism, and acute kidney failure (10393,10619,15589,15590,15593,15594,15596,15597,15599)(15600,16057,16835,25660,25673,25719,26439,31562,59709,59716)(59720,59740,59787,59820,59826,59882,59889,59900,91722,97214,100522) (104563,108576,108577). These effects are most likely to occur when 20-30 grams of licorice products containing glycyrrhizin 400 mg or more is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,108574). However, some people may be more sensitive, especially those with hypertension, diabetes, heart problems, or kidney problems (15589,15593,15598,15600,59726,108576,108577) and even low or moderate consumption of licorice may cause hypertensive crisis or hypertension in normotensive individuals (1372,97213). The use of certain medications with licorice may also increase the risk of these adverse effects (108568,108577). One case report determined that the use of large doses of licorice in an elderly female stabilized on fludrocortisone precipitated hypokalemia and hypertension, requiring inpatient treatment (108568). Another case report describes severe hypokalemia necessitating intensive care treatment due to co-ingestion of an oral glycyrrhizin-specific product and hydrochlorothiazide for 1 month (108577). Glycyrrhetinic acid has a long half-life, a large volume of distribution, and extensive enterohepatic recirculation. Therefore, it may take 1-2 weeks before hypokalemia resolves (781,15595,15596,15597,15600). Normalization of the renin-aldosterone axis and blood pressure can take up to several months (781,15595,108568). Treatment typically includes the discontinuation of licorice, oral and intravenous potassium supplementation, and short-term use of aldosterone antagonists, such as spironolactone (108574,108577).
Chewing tobacco flavored with licorice has also been associated with toxicity. Chewing licorice-flavored tobacco, drinking licorice tea, or ingesting large amounts of black licorice flavored jelly beans or lozenges has been associated with hypertension and suppressed renin and aldosterone levels (12671,12837,97214,97215,97217,108574). One case report suggests that taking a combination product containing about 100 mg of licorice and other ingredients (Jintan, Morishita Jintan Co.) for many decades may be associated with hypoaldosteronism, even up to 5 months after discontinuation of the product (100522). In another case report, licorice ingestion led to hyperprolactinemia in a female (59901). Licorice-associated hypercalcemia has also been noted in a case report (59766).

Gastrointestinal ...Nausea and vomiting have been reported rarely following oral use of deglycyrrhizinated licorice (25694,59871). Intravenously, the glycyrrhizin constituent of licorice has rarely caused gastric discomfort, diarrhea, or nausea (59712,59915).

Immunologic ...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912). There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578).

Musculoskeletal ...In a case report, excessive glycyrrhizin-containing licorice consumption led to water retention and was thought to trigger neuropathy and carpal tunnel syndrome (59791).

Neurologic/CNS ...Orally, licorice containing larger amounts of glycyrrhizin may cause headaches. A healthy woman taking glycyrrhizin 380 mg daily for 2 weeks experienced a headache (59892). Intravenously, the glycyrrhizin constituent of licorice has rarely caused headaches or fatigue (59721). In a case report, licorice candy ingestion was associated with posterior reversible encephalopathy syndrome accompanied by a tonic-clonic seizure (97218).

Ocular/Otic ...Orally, consuming glycyrrhizin-containing licorice 114-909 grams has been associated with transient visual loss (59714).

Pulmonary/Respiratory ...Orally, large amounts of licorice might lead to pulmonary edema. In one case report, a 64-year old male consumed 1020 grams of black licorice (Hershey Twizzlers) containing glycyrrhizin 3.6 grams over 3 days, which resulted in pulmonary edema secondary to pseudohyperaldosteronism (31561). Intravenously, the glycyrrhizin constituent of licorice has caused cold or flu-like symptoms, although these events are not common (59712,59721).

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