South African Hoodia Gordonii 200 mg • Guarana extract • Magnolia bark extract • Citrus aurantium • Bioperine brand Black Pepper extract • Cha de Bugre • Ginseng .
Brand name products often contain multiple ingredients. To read detailed information about each ingredient, click on the link for the individual ingredient shown above.
Below is general information about the effectiveness of the known ingredients contained in the product PhenterLean HG. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
There is insufficient reliable information available about the effectiveness of Cha de Bugre.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product PhenterLean HG. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
LIKELY SAFE ...when used orally in amounts commonly found in foods. Bitter orange has Generally Recognized as Safe (GRAS) status in the US (4912,35751).
POSSIBLY SAFE ...when bitter orange essential oil is used topically or by inhalation as aromatherapy (6972,7107,98331,104186,104187,108642).
POSSIBLY UNSAFE ...when used orally for medicinal purposes. Although single doses of synephrine, or low daily doses used short-term, may be safe in healthy adults (2040,11269,15381,35757,35759,91681,97256,98332), laboratory analyses raise concerns that many marketed bitter orange products contain higher amounts of synephrine and other natural and synthetic amines than on the label, increasing the risk for serious stimulant-related adverse effects (104185). Additionally, there is a lack of agreement regarding a safe daily dose of synephrine. Health Canada has approved 50 mg of p-synephrine daily when used alone, or 40 mg of p-synephrine in combination with up to 320 mg of caffeine daily in healthy adults (91684). The Federal Institute for Risk Assessment in Germany recommends that supplements should provide no more than 6.7 mg of synephrine daily. This recommendation is meant to ensure that patients who frequently consume synephrine in conventional foods will receive no more than 25.7 mg daily (91290). These limits are intended to reduce the risk for serious adverse effects. There have been several case reports of ischemic stroke and cardiotoxicity including tachyarrhythmia, cardiac arrest, syncope, angina, myocardial infarction, ventricular arrhythmia, and death in otherwise healthy patients who have taken bitter orange extract alone or in combination with other stimulants such as caffeine (2040,6979,12030,13039,13067,14326,14342,91680).
PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in the amounts found in foods.
Bitter orange has Generally Recognized as Safe (GRAS) status in the US (4912).
PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally for medicinal purposes.
There are case reports of cardiotoxicity including tachyarrhythmia, syncope, and myocardial infarction in otherwise healthy adults who have taken bitter orange extract alone or in combination with other stimulants such as caffeine (2040,6979,12030,13039,13067,14326,14342,91680). The effects of bitter orange during lactation are unknown; avoid use.
LIKELY SAFE ...when used orally in amounts commonly found in foods. Black pepper has Generally Recognized as Safe (GRAS) status in the US (4912).
POSSIBLY SAFE ...when black pepper oil is applied topically. Black pepper oil is nonirritating to the skin and is generally well tolerated (11). ...when black pepper oil is inhaled through the nose or as a vapor through the mouth, short-term. Black pepper oil as a vapor or as an olfactory stimulant has been used with apparent safety in clinical studies for up to 3 days and 30 days, respectively (29159,29160,29161,90502). There is insufficient reliable information available about the safety of black pepper when used orally in medicinal amounts.
CHILDREN: LIKELY SAFE
when used orally in amounts commonly found in foods (11).
CHILDREN: POSSIBLY UNSAFE
when used orally in large amounts.
Fatal cases of pepper aspiration have been reported in some patients (5619,5620). There is insufficient reliable information available about the safety of topical pepper oil when used in children.
PREGNANCY: LIKELY SAFE
when used orally in amounts commonly found in foods (11).
PREGNANCY: LIKELY UNSAFE
when used orally in large amounts.
Black pepper might have abortifacient effects (11,19); contraindicated. There is insufficient reliable information available about the safety of topical pepper when used during pregnancy.
LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods (11).
There is insufficient reliable information available about the safety of black pepper when used in medicinal amounts during breast-feeding.
There is insufficient reliable information available about the safety of Cha de Bugre.
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
LIKELY SAFE ...when consumed in amounts typically found in foods. Guarana has Generally Recognized as Safe (GRAS) status for use in foods in the US (4912).
POSSIBLY SAFE ...when used orally and appropriately, short-term (12). Guarana contains caffeine. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, doses of caffeine up to 400 mg daily are not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806).
POSSIBLY UNSAFE ...when used orally long-term or in high doses. Guarana contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other significant adverse effects. Acute use of high doses, typically above 400 mg per day, has been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances (11832,95503,98806). These effects would not be expected to occur with the consumption of decaffeinated guarana.
LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, or prior caffeine use (11832,54425).
PREGNANCY: POSSIBLY SAFE
when consumed in amounts commonly found in foods.
Due to the caffeine content of guarana, intake should be closely monitored during pregnancy to ensure moderate consumption. Although it is not considered a teratogen, caffeine crosses the placenta and causes dose-dependent increases in fetal blood concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015,98806). In some studies, consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in individuals with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, caffeine can be safely consumed in doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). Advise individuals to keep caffeine consumption below 300 mg daily during pregnancy.
PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts over 300 mg daily.
Although it is not considered a teratogen, caffeine crosses the placenta and causes dose-dependent increases in fetal blood concentrations (4260,98806). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise keeping caffeine consumption from all sources below 300 mg daily. High maternal doses of caffeine throughout pregnancy have resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711).
LACTATION: POSSIBLY SAFE
when used orally in amounts commonly found in foods.
Due to the caffeine content of guarana, intake should be closely monitored when breast-feeding. Breast milk concentrations of caffeine are thought to be approximately 50% of serum concentrations (9892).
LACTATION: POSSIBLY UNSAFE
when used orally in large amounts.
Consumption of guarana might cause irritability and increased bowel activity in nursing infants (6026). Large doses or excessive intake of guarana should be avoided when breast-feeding.
There is insufficient reliable information available about the safety of hoodia.
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
POSSIBLY SAFE ...when used orally and appropriately, short-term. A specific product containing magnolia extract and phellodendron extract (Relora, Next Pharmaceuticals, Inc.) has been used with apparent safety in clinical trials at a dose of 250 mg two to three times daily for up to 6 weeks (14349,34246,94904). ...when used topically in a toothpaste for up to 6 months (92464).
PREGNANCY: UNSAFE
when the magnolia flower bud is used orally due to reports of uterine stimulant activity (11953).
There is insufficient reliable information available about the safety of using magnolia bark during pregnancy; avoid using.
LACTATION:
Insufficient reliable information available; avoid using.
Below is general information about the interactions of the known ingredients contained in the product PhenterLean HG. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, bitter orange might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Some clinical research shows that drinking a tea containing bitter orange and Indian snakeroot reduces fasting and postprandial glucose levels in patients with type 2 diabetes who are using antidiabetes drugs (35751). However, it is unclear if these effects are due to bitter orange, Indian snakeroot, or the combination. An animal study also shows that p-synephrine in combination with gliclazide , a sulfonylurea, causes an additional 20% to 44% decrease in glucose levels when compared with gliclazide alone (95658).
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Bitter orange might increase blood pressure and heart rate when taken with caffeine.
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Bitter orange might affect colchicine levels.
Colchicine is a substrate of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Bitter orange has been reported to inhibit CYP3A4 and increase levels of CYP3A4 substrates (7029,11362,93470). However, one small clinical study in healthy adults shows that drinking bitter orange juice 240 mL twice daily for 4 days and taking a single dose of colchicine 0.6 mg on the 4th day decreases colchicine peak serum levels by 24%, time to peak serum level by 1 hour, and overall exposure to colchicine by 20% (35762). The clinical significance of this finding is unclear.
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Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.
In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes (91878). This effect has not been reported in humans.
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Bitter orange might increase levels of drugs metabolized by CYP3A4.
Small clinical studies suggest that single or multiple doses of freshly squeezed bitter orange juice 200-240 mL can inhibit CYP3A4 metabolism of drugs (7029,11362,93470), causing increased drug levels and potentially increasing the risk of adverse effects. However, the extent of the effect of bitter orange on CYP3A4-mediated drug interactions is unknown. Some evidence suggests that bitter orange selectively inhibits intestinal CYP3A4, but not hepatic CYP3A4. Its effect on P-glycoprotein, which strongly overlaps with CYP3A4 interactions, is unclear (7029,11269,11270,11362). One small clinical study shows that drinking 8 ounces of freshly squeezed bitter orange juice has no effect on cyclosporine, which seems to be more dependent on hepatic CYP3A4 and P-glycoprotein than intestinal CYP3A4 (11270).
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Bitter orange might increase blood levels of dextromethorphan.
One small clinical study shows that bitter orange juice increases dextromethorphan levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition (11362). Theoretically, bitter orange might increase the risk for dextromethorphan-related adverse effects.
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Bitter orange might increase blood levels of felodipine.
One small clinical study shows that bitter orange juice increases felodipine levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition (7029). Theoretically, bitter orange might increase the risk for felodipine-related adverse effects.
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Bitter orange might increase blood levels of indinavir.
One small clinical study shows that bitter orange juice slightly increases indinavir levels, but this effect is likely to be clinically insignificant. Bitter orange selectively inhibits intestinal cytochrome P450 3A4 (CYP3A4); however, the metabolism of indinavir seems to be more dependent on hepatic CYP3A4 (11269). The effect of bitter orange on other protease inhibitors has not been studied.
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Bitter orange might increase blood levels of midazolam.
One small clinical study shows that bitter orange juice can increase midazolam levels, likely through inhibition of cytochrome P450 3A4 (CYP3A4) (7029). Theoretically, bitter orange might increase the risk of midazolam-related adverse effects.
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Theoretically, taking MAOIs with synephrine-containing bitter orange preparations might increase the hypertensive effects of synephrine, potentially leading to hypertensive crisis.
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Theoretically, bitter orange might have an additive effect when combined with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias.
One case report suggests that taking bitter orange in combination with other stimulants such as caffeine might prolong the QT interval in some patients (13039).
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Bitter orange juice might increase blood levels of sildenafil.
A small clinical study in healthy adult males shows that drinking freshly squeezed bitter orange juice 250 mL daily for 3 days and taking a single dose of sildenafil 50 mg on the 3rd day increases the peak plasma concentration of sildenafil by 18% and the overall exposure to sildenafil by 44%. Theoretically, this may be due to inhibition of cytochrome P450 3A4 by bitter orange (93470).
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Theoretically, bitter orange might increase the risk of hypertension and adverse cardiovascular effects when taken with stimulant drugs.
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Theoretically, black pepper might increase the effects and side effects of amoxicillin.
Animal research shows that taking piperine, a constituent of black pepper, with amoxicillin increases plasma levels of amoxicillin (29269). This has not been reported in humans.
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Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation (29206). This has not been reported in humans.
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Theoretically, black pepper might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that piperine, a constituent of black pepper, can reduce blood glucose levels (29225). Monitor blood glucose levels closely. Dose adjustments might be necessary.
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Theoretically, black pepper might increase blood levels of atorvastatin.
Animal research shows that taking piperine, a constituent of black pepper, 35 mg/kg can increase the maximum serum concentration of atorvastatin three-fold (104188). This has not been reported in humans.
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Theoretically, black pepper might increase blood levels of carbamazepine, potentially increasing the effects and side effects of carbamazepine.
One clinical study in patients taking carbamazepine 300 mg or 500 mg twice daily shows that taking a single 20 mg dose of purified piperine, a constituent of black pepper, increases carbamazepine levels. Piperine may increase carbamazepine absorption by increasing blood flow to the GI tract, increasing the surface area of the small intestine, or inhibiting cytochrome P450 3A4 (CYP3A4) in the gut wall. Absorption was significantly increased by 7-10 mcg/mL/hour. The time to eliminate carbamazepine was also increased by 4-8 hours. Although carbamazepine levels were increased, this did not appear to increase side effects (16833). In vitro research also shows that piperine can increase carbamazepine levels by 11% in a time-dependent manner (103819).
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Theoretically, black pepper might increase the effects and side effects of cyclosporine.
In vitro research shows that piperine, a constituent of black pepper, increases the bioavailability of cyclosporine (29282). This has not been reported in humans.
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Theoretically, black pepper might increase levels of drugs metabolized by CYP1A1.
In vitro research suggests that piperine, a constituent of black pepper, inhibits CYP1A1 (29213). This has not been reported in humans.
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Theoretically, black pepper might increase levels of drugs metabolized by CYP2B1.
In vitro research suggests that piperine, a constituent of black pepper, inhibits CYP2B1 (29332). This has not been reported in humans.
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Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.
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Theoretically, black pepper might increase levels of drugs metabolized by CYP3A4.
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Theoretically, black pepper might increase blood levels of lithium due to its diuretic effects. The dose of lithium might need to be reduced.
Black pepper is thought to have diuretic properties (11).
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Black pepper might increase blood levels of nevirapine.
Clinical research shows that piperine, a constituent of black pepper, increases the plasma concentration of nevirapine. However, no adverse effects were observed in this study (29209).
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Theoretically, black pepper might increase levels of P-glycoprotein substrates.
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Theoretically, black pepper might increase the sedative effects of pentobarbital.
Animal research shows that piperine, a constituent of black pepper, increases pentobarbital-induced sleeping time (29214).
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Black pepper might increase blood levels of phenytoin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption, slow elimination, and increase levels of phenytoin (537,14442). Taking a single dose of black pepper 1 gram along with phenytoin seems to double the serum concentration of phenytoin (14375). Consuming a soup with black pepper providing piperine 44 mg/200 mL of soup along with phenytoin also seems to increase phenytoin levels when compared with consuming the same soup without black pepper (14442).
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Black pepper might increase blood levels of propranolol.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of propranolol (538).
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Black pepper might increase blood levels of rifampin.
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Black pepper might increase blood levels of theophylline.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of theophylline (538).
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Theoretically, guarana might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Guarana contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).
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Theoretically, alcohol might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Concomitant use of alcohol can increase caffeine serum concentrations and the risk of caffeine adverse effects. Alcohol reduces caffeine metabolism (6370).
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Theoretically, guarana may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
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Theoretically, taking guarana with antidiabetes drugs might interfere with blood glucose control.
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Theoretically, concomitant use might increase the clinical effects of beta-adrenergic agonists.
Guarana contains caffeine. Theoretically, concomitant use of large amounts of caffeine might increase cardiac inotropic effects of beta-agonists (15).
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Theoretically, guarana might reduce the effects of carbamazepine and increase the risk for convulsions.
Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when given to animals in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine two-fold in healthy individuals (23562).
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Theoretically, concomitant use might increase the effects and adverse effects of caffeine in guarana.
Guarana contains caffeine. Cimetidine decreases the rate of caffeine clearance by 31% to 42% (11736).
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Theoretically, guarana might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Guarana contains caffeine. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients more sensitive to the interaction between clozapine and caffeine (13741).
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Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in guarana.
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Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
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Theoretically, guarana might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Guarana contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole than adenosine-induced stress testing (11771).
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Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
In human research, disulfiram decreases the clearance and increases the half-life of caffeine (11840).
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Theoretically, using guarana with diuretic drugs might increase the risk of hypokalemia.
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Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Guarana contains caffeine. Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death (1275,6486,10307).
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Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Estrogen inhibits caffeine metabolism (2714).
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Theoretically, guarana might reduce the effects of ethosuximide and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). This effect has not been observed in humans.
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Theoretically, guarana might reduce the effects of felbamate and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). This effect has not been observed in humans.
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Theoretically, fluconazole might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Fluconazole decreases caffeine clearance by approximately 25% (11022).
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Theoretically, guarana might increase the levels and adverse effects of flutamide.
Guarana contains caffeine. In vitro evidence shows that caffeine can inhibit the metabolism of flutamide (23553). However, this effect has not been reported in humans.
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Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Fluvoxamine reduces caffeine metabolism (6370).
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Theoretically, abrupt guarana withdrawal might increase the levels and adverse effects of lithium.
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Theoretically, metformin might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Animal research shows that metformin can reduce caffeine metabolism (23571). However, this effect has not been reported in humans.
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Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Methoxsalen can reduce caffeine metabolism (23572).
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Theoretically, mexiletine might increase the levels and adverse effects of caffeine.
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Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Guarana contains caffeine. Caffeine has been shown to inhibit MAO-A and -B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.
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Theoretically, concomitant use might increase the risk of hypertension.
Guarana contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).
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Theoretically, guarana might decrease the effects of pentobarbital.
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Theoretically, guarana might reduce the effects of phenobarbital and increase the risk for convulsions.
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Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.
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Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
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Theoretically, guarana might reduce the effects of phenytoin and increase the risk for convulsions.
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Theoretically, guarana might increase the levels and clinical effects of pioglitazone.
Guarana contains caffeine. Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.
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Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
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Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Guarana contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents (11739).
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Theoretically, concomitant use might increase stimulant adverse effects.
Guarana contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).
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Theoretically, terbinafine might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).
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Theoretically, guarana might increase the levels and adverse effects of theophylline.
Guarana contains caffeine. Large amounts of caffeine might decrease theophylline clearance by 23% to 29% (11741).
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Theoretically, guarana might increase the levels and adverse effects of tiagabine.
Guarana contains caffeine. Animal research shows that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).
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Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. In vitro evidence shows that ticlopidine can inhibit the metabolism of caffeine (23557). However, this interaction has not been reported in humans.
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Theoretically, guarana might reduce the effects of valproate and increase the risk for convulsions.
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Theoretically, verapamil might increase the levels and adverse effects of caffeine.
Verapamil increases plasma caffeine concentrations by 25% (11741).
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Animal research shows that a steroid glycoside of hoodia, gordonoside F, increases glucose-stimulated insulin secretion by activating GPR119. This effect enhances glucose disposal (91614). Theoretically, concomitant use of hoodia with antidiabetes medications may enhance blood glucose-lowering effects and increase the risk of hypoglycemia. Some antidiabetes medications include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
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Clinical research shows that hoodia can increase blood pressure (18052). Theoretically, concomitant use of hoodia with antihypertensive drugs might decrease the effectiveness of the antihypertensive drugs and increase the risk of hypertension. Some antihypertensive drugs include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.
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Evidence from in vitro research shows that hoodia may stimulate beta-adrenergic receptors (91607). Also, clinical research shows that hoodia can increase blood pressure and heart rate (18052). Theoretically, using hoodia with beta-blockers might decrease the effects of these medications. Some beta-blocker drugs include atenolol (Tenormin), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal).
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Animal research shows that a steroid glycoside of hoodia, gordonoside F, increases glucose-stimulated insulin secretion by activating GPR119 (91614). Theoretically, concomitant use of hoodia with insulin may enhance the blood glucose-lowering effects of insulin. Blood glucose levels should be monitored.
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Theoretically, magnolia might have additive effects and increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.
In vitro research shows that the chemicals magnolol and honokiol, isolated from magnolia bark, inhibit platelet aggregation that is experimentally induced by collagen and arachidonic acid. However, they do not inhibit platelet aggregation that is induced by adenosine diphosphate, platelet-activating factor, or thrombin (18273). This interaction has not been reported in humans.
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Theoretically, concomitant use of large doses of magnolia bark and CNS depressants might have additive effects.
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Below is general information about the adverse effects of the known ingredients contained in the product PhenterLean HG. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally, bitter orange might be unsafe when used in medicinal amounts.
Topically and when inhaled as aromatherapy, bitter orange seems to be well tolerated.
Most Common Adverse Effects:
Orally: Hypertension and tachycardia, particularly when used in combination with caffeine and/or other stimulant ingredients.
Topically: Skin irritation.
Serious Adverse Effects (Rare):
Orally: Myocardial infarction, QT prolongation, seizures, stroke, syncope, tachyarrhythmia, and ventricular fibrillation have been reported in patients taking bitter orange in combination with other ingredients. It is unclear if these effects are due to bitter orange, other ingredients, or the combination.
Cardiovascular
...Bitter orange, which contains adrenergic agonists synephrine and octopamine, may cause hypertension and cardiovascular toxicity when taken orally (2040,6969,6979).
Studies evaluating the effect of bitter orange on cardiovascular parameters have been mixed. Several studies show that taking bitter orange alone or in combination with caffeine increases blood pressure and heart rate. In one clinical study, bitter orange in combination with caffeine increased systolic and diastolic blood pressure and heart rate in otherwise healthy normotensive adults (13657). In another study, a single dose of bitter orange 900 mg, standardized to 6% synephrine (54 mg), also increased systolic and diastolic blood pressure and heart rate for up to 5 hours in young, healthy adults (13774). Using half that dose of bitter orange and providing half as much synephrine, did not seem to significantly increase blood pressure or QT interval in healthy adults (14311). Increased diastolic, but not systolic, blood pressure or heart rate also occurred in a clinical trial involving a specific supplement containing synephrine 21 mg and caffeine 304 mg (Ripped Fuel Extreme Cut, Twinlab) (35743). Synephrine given intravenously to males increased systolic blood pressure, but lacked an effect on diastolic blood pressure or heart rate (12193).
In clinical research and case reports, tachycardia, tachyarrhythmia, QT prolongation, ischemic stroke, variant angina, and myocardial infarction have occurred with use of bitter orange or synephrine-containing multi-ingredient products (12030,13039,13067,13091,13657,14326,35749,91680). In one case report, a combination product containing bitter orange may have masked bradycardia and hypotension while exacerbating weight loss in a 16 year-old female with an eating disorder taking the product for weight loss (35740). From 1998 to 2004, Health Canada received 16 reports of serious adverse cardiovascular reactions such as tachycardia, cardiac arrest, ventricular fibrillation, blackout, and collapse. In two of these cases, the patient died. In almost all of these cases, bitter orange was combined with another stimulant such as caffeine, ephedrine, or both (14342).
Other research has found no significant effect of bitter orange on blood pressure or heart rate. Several clinical studies have reported that, when taken as a single dose or in divided doses ranging from 20-100 mg for one day, p-synephrine had no significant effect on blood pressure, heart rate, electrocardiogram results or adverse cardiovascular events in healthy adults (35772,91681,91681,95659,101708) Similarly, no difference in blood pressure, heart rate or electrocardiogram results were reported when p-synephrine from bitter orange (Advantra Z/Kinetic; Nutratech/Novel Ingredients Inc.) was taken for 6 weeks in healthy patients (11268). Another clinical study showed no significant effect of bitter orange (Nutratech Inc.), standardized to synephrine 20 mg, on blood pressure or heart rate when taken daily for 8 weeks in healthy males (95656). In other research, changes in blood pressure, heart rate, or QTc interval were lacking when bitter orange was given alone or in combination with caffeine and green tea (14311,35753,35755,35764,35769,35770). In one study of healthy adults, taking a single dose of p-synephrine 103 mg actually reduced mean diastolic blood pressure by 0.4-4 mmHg at 1 and 2 hours after administration when compared with placebo (95659).
A meta-analysis of clinical trials in adults with or without obesity suggests that taking p-synephrine 6-214 mg orally daily does not affect blood pressure or heart rate when used short-term, but modestly increases blood pressure and heart rate when taken for 56-60 days (109950).
The effect of bitter orange on blood pressure, heart rate, and electrocardiogram results in patients with underlying conditions, particularly cardiovascular disease, is unknown and requires further study.
Dermatologic ...Photosensitivity may occur, particularly in fair-skinned people (11909). In a clinical trial, topical application with bitter orange essential oil resulted in irritation (6972).
Endocrine ...Some clinical research shows that taking a specific supplement containing 21 mg of synephrine and 304 mg of caffeine (Ripped Fuel Extreme Cut, Twinlab) increases levels of postprandial glucose (35743). Other preliminary clinical research shows that taking a specific pre-workout supplement (Cellucor C4 Pre-Workout, Nutrabolt) along with a bitter orange extract standardized for synephrine 20 mg (Nutratech Inc.) 30 minutes once before exercise causes a significant 12% increase in glucose (95657); however, there is no difference in blood glucose when compared with placebo when this combination is taken daily for 8 weeks (95656). The effect of bitter orange itself is unclear.
Gastrointestinal ...Bitter orange has been linked to a report of ischemic colitis. In one case, a 52-year-old female developed ischemic colitis after taking a bitter orange-containing supplement (NaturalMax Skinny Fast, Nutraceutical Corporation) for a week. Symptoms resolved within 48 hours after discontinuing the supplement (15186). As this product contains various ingredients, the effect of bitter orange itself is unclear.
Musculoskeletal ...Unsteady gait has been noted in one case report of a patient taking bitter orange (13091). In another case, an otherwise healthy, Black male with sickle cell trait, developed severe rhabdomyolysis following ingestion of a specific weight loss product (Lipo 6, Nutrex Research Inc.), which contained synephrine and caffeine (16054). However, other preliminary clinical research shows that taking a specific pre-workout supplement (Cellucor C4 Pre-Workout, Nutrabolt) along with a bitter orange extract standardized for synephrine 20 mg (Nutratech Inc.), taken 30 minutes once before exercise (95657) or daily for 8 weeks, does not affect creatine kinase or serum creatinine levels when compared with placebo (95656). As these products contain various ingredients, the effect of bitter orange itself is unclear.
Neurologic/CNS ...Dizziness, difficulty in concentrating, memory loss, syncope, seizure, and stroke have been noted in case reports following bitter orange administration (13091,13039). Theoretically, bitter orange may trigger a migraine or cluster headache due to its synephrine and octopamine content (35768). When used as aromatherapy, bitter orange essential oil has also been reported to cause headache in some patients (104187). Sprint athletes taking the bitter orange constituent p-synephrine 3 mg/kg (Synephrine HCL 99%, Nutrition Power) 60 minutes before exercises and sprinting reported more nervousness (mean difference 0.9) when compared with placebo on a Likert scale. Although statistically significant, this difference is not considered clinically significant (95655).
General
...Orally, black pepper seems to be well tolerated when used in the amounts found in food or when taken as a medicine as a single dose.
Topically and as aromatherapy, black pepper oil seems to be well tolerated.
Most Common Adverse Effects:
Orally: Burning aftertaste, dyspepsia, and reduced taste perception.
Inhalation: Cough.
Serious Adverse Effects (Rare):
Orally: Allergic reaction in sensitive individuals.
Gastrointestinal ...Orally, black pepper can cause a burning aftertaste (5619) and dyspepsia (38061). Single and repeated application of piperine, the active constituent in black pepper, to the tongue and oral cavity can decrease taste perception (29267). By intragastric route, black pepper 1.5 grams has been reported to cause gastrointestinal microbleeds (29164). It is not clear if such an effect would occur with oral administration.
Immunologic ...In one case report, a 17-month-old male developed hives, red eyes, facial swelling, and a severe cough following consumption of a sauce containing multiple ingredients. Allergen skin tests were positive to both black pepper and cayenne, which were found in the sauce (93947).
Ocular/Otic ...Topically, ground black pepper can cause redness of the eyes and swelling of the eyelids (5619).
Pulmonary/Respiratory ...When inhaled through the nose as an olfactory stimulant, black pepper oil has been reported to cause cough in one clinical trial (29162).
...None reported.
General
...Orally, guarana is typically well tolerated when used in moderation.
Due to its caffeine content, use of large doses may be unsafe.
Most Common Adverse Effects:
Orally: Stomach burning and nausea.
Cardiovascular
...Orally, a case of premature ventricular contraction has been reported for a 51-year-old female who used guarana as part of a multi-ingredient herbal product (54372).
Guarana contains caffeine. Although acute administration of caffeine can increase blood pressure, regular consumption does not seem to increase either blood pressure or pulse, even in mildly hypertensive patients (1451,1452,2722). Also, epidemiological research suggests there is no association between caffeine consumption and increased incidence of hypertension. Habitual coffee consumption doesn't seem to be related to hypertension, but habitual consumption of sugared or diet cola is associated with development of hypertension (13739).
Combining ephedra with guarana can increase the risk of adverse effects. Cases of hypertension and chest pain have been reported for patients who took products containing guarana and ephedra (8644,54376). A case of cerebral infarction has also been reported for a patient consuming ephedra extract and guarana (48746). There is also a report of ischemic stroke in an athlete who consumed ephedra 40-60 mg, creatine monohydrate 6 grams, caffeine 400-600 mg, and a variety of other supplements daily for six weeks (1275).
Dermatologic ...Guarana contains caffeine. There are several case reports of urticaria after caffeine ingestion (36546,36448,36475).
Endocrine
...Guarana contains caffeine.
Some evidence shows caffeine is associated with fibrocystic breast disease, breast cancer, and endometriosis; however, this is controversial since findings are conflicting (8043). Restricting caffeine in people with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996). A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
Although the effects of guarana alone are not clear, the combination of guarana along with ephedra has been reported to cause increased blood glucose levels and decreased blood levels of potassium (54376).
Gastrointestinal ...Orally, guarana can cause a sensation of burning in the stomach and vomiting (54414,91487). These effects may be due to caffeine in guarana. Orally, caffeine can cause gastric irritation, nausea, and vomiting (11832,11838,13735). In infants, caffeine may also cause feeding intolerance and gastrointestinal irritation (6023).
Immunologic ...Guarana contains caffeine. When taken orally, caffeine can cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).
Musculoskeletal
...In a clinical trial of guarana extract, one person abandoned treatment due to symptoms of arthritis with edema.
It is not clear if this adverse effect is due to guarana (91487).
Cases of rhabdomyolysis and myoglobinuria have been reported in individuals that have taken products containing guarana in combination with ephedra and other herbal products. These adverse effects are thought to be related to the caffeine content of guarana (19154,36466).
Epidemiological evidence regarding the relationship between caffeine use and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium (2669,10202,11317). Women identified with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake, less than 300 mg per day, does not seem to significantly increase osteoporosis risk in most postmenopausal women with normal calcium intake (2669,6025,10202,11317).
Neurologic/CNS
...Orally, guarana can cause dizziness (91483).
The caffeine in guarana can cause insomnia (especially in children), nervousness, restlessness, dizziness, tremors, delirium, and convulsions. Other symptoms include headache, anxiety, and agitation (10755,11832,11838,13735,108016).
Taking guarana with ephedra can cause insomnia, irritability, dizziness, and headache (3719). The combination of ephedra and caffeine in guarana might also increase the risk of adverse effects such as jitteriness, seizures, and temporary loss of consciousness (2729,21015).
Ocular/Otic ...Guarana contains caffeine. When taken orally, caffeine can cause ringing in the ears (11832,11838,13735).
Psychiatric ...In a clinical trial, depression was reported by one person taking guarana extract (91483).
Renal ...Guarana contains caffeine. When taken orally, caffeine can cause diuresis (11832,11838,13735).
Other ...Guarana contains caffeine. The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Other researchers suggest symptoms such as headache; tiredness and fatigue; decreased energy, alertness, and attentiveness; drowsiness; decreased contentedness; depressed mood; difficulty concentrating; irritability; and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).
General ...Orally, hoodia has been reported to cause minor adverse effects including disturbances of skin sensation, headache, dizziness, giddiness, and nausea (18052). There is also concern that hoodia may increase blood pressure and heart rate (18052).
Cardiovascular ...Orally, hoodia might increase blood pressure and heart rate. Clinical research in healthy women shows that intake of purified hoodia extract containing steroid glycosides increases systolic blood pressure by 5.9 to 15.9 mmHg, diastolic blood pressure by 4.6 to 11.5 mmHg, and heart rate by 4.8 to 12.4 beats per minute (18052).
Dermatologic ...Orally, hoodia extract has been reported to cause disturbances of skin sensation (18052).
Gastrointestinal ...Orally, hoodia extract has been reported to cause nausea (18052).
Neurologic/CNS ...Orally, hoodia extract has been reported to cause headache, dizziness, and giddiness (18052).
General
...Orally, magnolia seems to be well tolerated.
Most Common Adverse Effects:
Topically: Contact dermatitis.
Dermatologic ...Topically, magnolia bark has been associated with reports of allergic contact dermatitis (92463,92468,95030,110709). In several cases, the use of anti-aging facial creams containing magnolia bark extract was associated with allergic contact dermatitis of the face (92463,92468,95030). In one case, the use of a vaginal gel containing magnolia bark extract was associated with allergic contact dermatitis of the vulva (110709). Symptoms typically resolve with the use of topical corticosteroids and discontinuation of magnolia bark extract (95030,110709). Patch testing suggests that the magnolia bark extract constituents magnolol and honokiol are responsible for this adverse effect (110709).
Endocrine ...In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported thyroid dysfunction (14349). However, it's not known if this side effect is related to magnolia or some other factor.
Gastrointestinal ...In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported heartburn (14349). However, it's not known if this side effect is related to magnolia or some other factor.
Neurologic/CNS ...In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported shaking hands and perilabial numbness. Another patient reported fatigue and headache (14349). However, it's not known if these side effects are related to magnolia or some other factor.
Psychiatric ...In a clinical trial of an oral combination product containing extracts of magnolia and phellodendron, one patient reported sexual dysfunction (14349). However, it's not known if this side effect is related to magnolia or some other factor.