POSSIBLY EFFECTIVE
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Metabolic syndrome.
Oral inositol seems to modestly improve lipid parameters, blood pressure, and insulin resistance in patients with metabolic syndrome.
Details: Some clinical research in postmenopausal adults with metabolic syndrome following a low-calorie diet shows that taking myo-inositol 2 grams twice daily for one year reduces total cholesterol by 29 mg/dL, triglycerides by 64 mg/dL, systolic and diastolic blood pressure by 9 mmHg and 6 mmHg, respectively, increases high-density lipoprotein (HDL) cholesterol by 6 mg/dL, and improves insulin resistance when compared with placebo. It did not reduce body mass index or waist circumference in these patients (91554). A meta-analysis of clinical studies in a mixed population shows similar effects on blood pressure, especially among postmenopausal adults with metabolic syndrome, at durations exceeding 8 weeks, and at doses of at least 4 grams (108820). Another clinical study in postmenopausal adults with metabolic syndrome and at risk for breast cancer shows that taking a combination of inositol and alpha-lipoic acid daily for 6 months, in combination with a low-calorie diet, reduces insulin resistance (HOMA-IR) by at least 20% when compared with a low-calorie diet alone. Also, taking inositol and alpha-lipoic acid seems to increase HDL cholesterol by about 6% and reduce triglycerides by 5% when compared to baseline (91543). It is unclear if these effects are due to inositol, alpha-lipoic acid, or the combination.
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Polycystic ovary syndrome (PCOS).
Oral inositol, often in combination with folic acid, seems to improve glycemic and lipid parameters, as well as ovulation and pregnancy rates, in some patients with PCOS.
Details: Inositol has shown modest benefit on metabolic parameters in patients with PCOS. A meta-analysis of clinical research shows that taking inositol (type not specified) modestly reduces fasting blood glucose, fasting insulin, total cholesterol, triglycerides, and testosterone levels when compared to control (98944). In individual clinical studies, taking D-chiro-inositol 1-1.2 grams or myo-inositol 4 grams with folic acid 400 mcg daily for 6 months decreases serum triglyceride and testosterone levels, modestly decreases blood pressure, and improves ovarian function (2028,91552). An unblinded clinical study shows that taking metformin with a combination of myo-inositol 550 mg and D-chiro-inositol 150 mg twice daily is associated with improved lipid parameters and postprandial insulin levels at 6 months when compared with metformin alone (108822). It is unclear if the improvement from baseline differed between groups. Other research shows that taking myo-inositol and D-chiro-inositol together may improve metabolic parameters faster than taking myo-inositol alone (91550).
Myo-inositol has also been compared with metformin in some clinical research, with some evidence of benefit (95085,95086). Meta-analyses of small clinical studies shows that taking myo-inositol 2-4 grams daily, with or without folic acid, for 12-24 weeks does not improve fasting insulin, insulin resistance (HOMA-IR), androgen levels, body mass index (BMI), or waist-hip ratio when compared with metformin 1.5-2.5 grams daily, although it seems to have a lower risk of adverse effects (100705,108823). These analyses are limited due to the small size, methodological issues, and high heterogeneity of the included studies.
Other research has evaluated the effects of inositol on ovulation and pregnancy outcomes. Some research suggests that inositol increases ovulation rate in patients with PCOS (98944). A small clinical study shows that taking myo-inositol 4 grams and folic acid 400 mcg (Inofolic, Lo.Li.Pharma) daily for three spontaneous cycles induces ovulation in about 62% of individuals with anovulatory PCOS and insulin resistance. Adding clomiphene citrate with myo-inositol induces ovulation in about 72% of the patients who remain anovulatory after treatment with myo-inositol alone (91547). Another clinical study shows that taking a combination of inositol 2 grams, folic acid 200 mcg, and N-acetyl cysteine 600 mg (Ovaric HP, Just Pharma) twice daily for 12 months improves ovulation rates in PCOS patients with oligomenorrhea, regardless of insulin sensitivity at baseline (91553). Some research has also investigated the effects of taking both isomers of inositol concomitantly. Taking myo-inositol 550 mg plus D-chiro-inositol 13.8 mg (Inofolic Combi, Lo.Li.Pharma) twice daily, beginning 12 weeks before ovarian hyperstimulation and continuing throughout pregnancy, improves oocyte quality when compared to treatment with D-chiro-inositol alone. The combination appears to increase fertilization rate in patients aged 35 years or younger, but not those older than 35 years (91544). Other clinical research shows that taking myo-inositol 550 mg and D-chiro-inositol 150 mg twice daily for 12 weeks improves pregnancy rates and live birth rates by an additional 10% and 11%, respectively, when compared with myo-inositol 550 mg plus D-chiro-inositol 13.8 mg. The higher-dose combination also resulted in a 15% lower rate of ovarian hyperstimulation syndrome when compared with those taking the lower dose of D-chiro-inositol (102317).
Research has also evaluated the effects of inositol on other pertinent clinical outcomes in PCOS. Several small clinical studies show that taking the combination of myo-inositol and D-chiro-inositol, alone or in combination with metformin, improves menstrual cycle irregularity when compared with metformin alone, but not as much as a taking a combined hormonal contraceptive (108822,108824). The validity of these findings is limited by the unblinded nature of the studies. Also, a small clinical study shows that taking metformin with myo-inositol 550 mg and D-chiro-inositol 150 mg twice daily is associated with improved acne, but not hirsutism, at 6 months, when compared with metformin alone (108822). It is unclear if the improvement from baseline differed between groups. The validity of these findings is limited by the unblinded nature of the study.
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Preterm labor.
Oral inositol in combination with folic acid seems to prevent preterm labor in individuals at risk for gestational diabetes.
Details: A meta-analysis of five clinical trials in individuals at risk for gestational diabetes shows that taking myo-inositol plus folic acid daily, beginning during the first trimester and continuing throughout pregnancy, decreases the risk of preterm delivery by 64% when compared with folic acid alone. Patients in all but one study included in this analysis took myo-inositol 2 grams plus folic acid 200 mcg twice daily, while patients in the other study took myo-inositol 1100 mg plus D-chiro-inositol 27.6 mg and folic acid 400 mcg daily (100706). It's unclear if these results are generalizable to individuals with a low risk for gestational diabetes.
POSSIBLY INEFFECTIVE
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Acute respiratory distress syndrome (ARDS).
Oral or intravenous inositol does not seem to prevent ARDS in preterm infants and may be associated with worsened outcomes.
Details: Historically, small clinical trials in infants with or at risk for ARDS have suggested that myo-inositol, given parenterally and enterally for 5-10 days, might improve survival and reduce the risk of death and serious complications (2191,2192,91546). However, a large, high-quality clinical study in infants born at less than 28 weeks' gestation at risk for ARDS shows that myo-inositol 40 mg/kg given intravenously and then enterally every 12 hours for up to 70 days does not reduce the risk of death or retinopathy of prematurity (ROP). In fact, the rate of death or type 1 ROP increased by 7% in the myo-inositol group when compared to the control group, and a higher incidence of adverse events in the myo-inositol group, including poor perfusion, hypotension, and infections, led to early trial discontinuation (98946). Long-term follow-up until 24 months corrected age confirms that the initial increase in mortality rate in the myo-inositol group remained stable; however, there was no difference in a composite outcome of death or survival with moderate or severe neurodevelopmental impairment, as well as no difference in the risk of ROP, between the treatment and control groups (108819). The most recent meta-analysis, which incorporates this large clinical study, concludes that inositol supplementation does not reduce the risk of death in infants at risk for ARDS (102319).
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Anxiety.
Oral inositol does not seem to be beneficial for patients with anxiety.
Details: A meta-analysis of four clinical trials shows that taking inositol orally does not improve anxiety severity in patients with anxiety disorders, including obsessive-compulsive disorder, panic disorder, or post-traumatic stress disorder, when compared with placebo (91549).
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Depression.
Oral inositol does not seem to be beneficial for patients with depression.
Details: A meta-analysis of seven clinical trials shows that inositol does not significantly improve symptoms of depression in patients with bipolar depression, major depressive disorder, or premenstrual dysphoric disorder (PMDD) (91549). While limited research shows that patients receiving inositol for 4 weeks may improve, patients initially responding to inositol seem to relapse rapidly upon discontinuation of treatment (2026,2185). Additionally, taking inositol with a selective serotonin reuptake inhibitor (SSRI) doesn't appear to improve the effectiveness of SSRI therapy or improve depression in SSRI treatment failures (2025,10851).
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Diabetic neuropathy.
Oral inositol does not seem to be beneficial for patients with diabetic neuropathy.
Details: Most preliminary clinical research shows that taking inositol orally doesn't improve the symptoms of diabetic neuropathy (2193,2194,2195).
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Retinopathy of prematurity.
Oral or intravenous inositol does not seem to prevent retinopathy of prematurity (ROP) in preterm infants.
Details: A meta-analysis of six clinical trials shows that myo-inositol, given parenterally and/or enterally, does not seem to reduce the risk of ROP when compared with placebo in preterm infants (100704). A large, high-quality clinical study included in this meta-analysis shows that myo-inositol 40 mg/kg given intravenously and then enterally every 12 hours for up to 70 days does not reduce the risk of death or ROP in infants born at less than 28 weeks' gestation. In fact, the rate of death or type 1 ROP increased by 7% in the myo-inositol group when compared with placebo and a higher incidence of adverse events in the myo-inositol group, including poor perfusion, hypotension, and infections, led to early trial discontinuation (98946). Long-term follow-up until 24 months corrected age confirms that the initial increase in mortality rate in the myo-inositol group remained stable; however, there was no difference in a composite outcome of death or survival with moderate or severe neurodevelopmental impairment, as well as no difference in the risk of ROP, between the treatment and control groups (108819).
INSUFFICIENT RELIABLE EVIDENCE to RATE
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Age-related testosterone deficiency.
It is unclear if oral D-chiro-inositol is beneficial in patients with age-related testosterone deficiency.
Details: A very small clinical study in males aged 65-75 years with low-normal morning testosterone levels and signs and symptoms of androgen deficiency shows that taking D-chiro-inositol 600 mg twice daily for 30 days improves sexual function and physical strength when compared with baseline (108821). The validity of these findings is limited by the lack of a comparator group.
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Bipolar disorder.
It is unclear if oral inositol is beneficial in patients with bipolar disorder.
Details: Preliminary clinical research in children aged 5-12 with bipolar disorder shows that taking a combination of inositol 80 mg/kg (maximum 2 grams) and eicosapentaenoic acid (EPA; Nordic Naturals) 3 grams daily for 12 weeks moderately reduces manic and depressive symptoms as well as symptoms of anxiety and oppositional defiant disorder. This improvement is greater than what is seen when either ingredient is taken alone (95092).
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Chemotherapy-induced leukopenia.
Oral inositol has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Details: A small clinical study in adults undergoing breast cancer surgery and adjuvant chemotherapy shows that taking inositol orally 390 mg twice daily and applying IP-6 gel 4% twice daily to the surgical site, starting 2 weeks before adjuvant chemotherapy and stopping 2 weeks after the last cycle, attenuates reductions in white and red blood cell counts when compared with no intervention. Using inositol and IP-6 also improves breast and arm symptom scores and some quality of life scores; however, these improvements were not consistent over time.
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Diabetes.
It is unclear if oral inositol is beneficial for the treatment of type 1 diabetes or the prevention of gestational diabetes.
Details: Preliminary clinical research in patients with type 1 diabetes and a body mass index of at least 25 kg/m2 shows that taking a specific combination product containing D-chiro-inositol and folic acid (Chirofol 500, LJ Pharma) daily for 6 months, along with insulin therapy, decreases glycated hemoglobin (HbA1c) by approximately 0.5% when compared to taking folic acid alone with insulin therapy. However, there was no difference between groups with respect to insulin resistance or body mass index (95088).
Most research shows that taking inositol during pregnancy prevents gestational diabetes. However, most studies conducted to date are of low quality and it is unclear if the results are generalizable. Most clinical research shows that taking myo-inositol 2 grams plus folic acid 200 mcg twice daily (usually as Inofolic, Lo.Li. Pharma International), beginning during the first trimester and continuing throughout pregnancy, decreases the incidence of gestational diabetes by 57% to 92% when compared with folic acid alone in patients at risk for gestational diabetes. Myo-inositol seems to be more effective than D-chiro-inositol (91545,91548,95083,95084,100706,103750,104688). However, supplementation with lower doses of inositol, mimicking natural inositol occurring in the body, may not be effective. One clinical study shows that taking a combination of myo-inositol 1.1 grams, D-chiro-inositol 27.6 mg, and folic acid 400 mcg (Inofolic Combi, Lo.Li. Pharma International) daily during pregnancy does not decrease the incidence of gestational diabetes when compared with folic acid alone in patients with a family history of diabetes (95082,103750).
In patients eventually diagnosed with gestational diabetes, one small clinical study shows that taking myo-inositol 2 grams reduces the number of patients requiring insulin by at least 50% (104688), although another small clinical study shows that adding D-chiro-inositol, myo-inositol, or both to folic acid does not affect insulin resistance when compared with placebo (98945).
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Dyslipidemia.
Although there has been interest in using oral inositol for hypercholesterolemia and hypertriglyceridemia, there is insufficient reliable information about the clinical effects of inositol for these conditions.
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Hypertension.
Although there has been interest in using oral inositol for hypertension, there is insufficient reliable information about the clinical effects of inositol for this condition.
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Infertility.
It is unclear if oral inositol is beneficial in patients undergoing intracytoplasmic sperm injection (ICSI).
Details: Several small studies in patients undergoing ICSI show that taking a specific combination product containing myo-inositol 4 grams and folic acid 400 mcg (Inofolic, Lo.Li. Pharma International S.r.l) by mouth daily, starting 1-3 months before ICSI and continuing until ovulation, improves fertilization rate, but does not improve implantation or pregnancy rates, when compared with taking folic acid alone (103752,108825).
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Insomnia.
It is unclear if oral inositol is beneficial for improving sleep during pregnancy.
Details: Clinical research shows that taking myo-inositol 2 grams plus folic acid 200 mcg (Inofolic, Lo.Li. Pharma International) before bed for 10 weeks, starting at 14 weeks gestation, improves overall measures of sleep quality by a small amount when compared with folic acid alone. However, this improvement was not maintained until 37-38 weeks' gestation. Also, the study was not limited to patients with poor sleep quality during pregnancy, but to any healthy pregnant individual (104687).
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Lithium-induced side effects.
It is unclear if oral inositol is beneficial for reducing lithium-induced side effects.
Details: A small clinical study suggests that taking inositol 6 grams daily for 10 weeks may improve psoriasis associated with lithium therapy when compared with baseline (11972). However, taking inositol orally does not seem to improve other lithium-induced adverse effects, such as tremor, thirst, and changes in thyroid and adrenal function (2027).
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Lung cancer.
It is unclear if oral inositol is beneficial for slowing the rate of bronchial dysplasia.
Details: Preliminary clinical research in smokers with bronchial dysplasia considered at high risk for lung cancer shows that taking myo-inositol (Tsuno Food Industries Co., Ltd.) 9 grams orally once daily for 2 weeks then twice daily for 6 months, does not increase the rate of complete or partial response when compared with placebo (95090).
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Obsessive-compulsive disorder (OCD).
It is unclear if oral inositol is beneficial in patients with OCD.
Details: One preliminary clinical study in adults with OCD shows that taking inositol 18 grams daily for 6 weeks improves Yale-Brown Obsessive Compulsive Scale scores when compared with placebo (2186). However, taking inositol does not seem to improve the severity or type of OCD symptoms in patients already taking a selective serotonin reuptake inhibitor (91556). Both of these studies were small, and treatment was administered for only 6 weeks.
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Panic disorder.
Oral inositol seems to improve symptoms of panic disorder.
Details: A very small clinical study shows that taking inositol 12 grams daily reduces the severity and rate of panic attacks and the severity of agoraphobia over 4 weeks of treatment when compared with placebo (2184). Another very small clinical study shows that taking inositol 18 grams daily for one month may be as effective as fluvoxamine 150 mg daily for treatment of panic disorder (10387). However, the one-month duration may not have provided adequate time to see the full effects of fluvoxamine.
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Post-traumatic stress disorder (PTSD).
It is unclear if oral inositol is beneficial in patients with PTSD.
Details: Preliminary clinical research shows that taking inositol 12 grams daily for 4 weeks does not improve distress when compared with placebo in patients with PTSD (91557).
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Pregnancy-induced hypertension.
It is unclear if oral inositol is beneficial for preventing hypertension during pregnancy.
Details: In patients with a body mass index (BMI) between 25-29.9 kg/m2, preliminary clinical research shows that taking myo-inositol 2 grams plus folic acid 200 mcg (Inofolic, Lo.Li. Pharma International) twice daily, beginning during the first trimester and continuing throughout pregnancy, decreases the incidence of pregnancy-induced hypertension by 66% when compared with folic acid alone (104688).
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Psoriasis.
It is unclear if oral or topical inositol is beneficial for improving symptoms of psoriasis.
Details: One small clinical study shows that taking inositol 6 grams daily for 10 weeks does not improve symptoms of psoriasis in a small group of patients when compared to baseline. However, taking this dose of inositol has a moderate effect on overall symptoms in patients with psoriasis related to lithium use (11972). Preliminary clinical research also shows that topical use of D-chiro-inositol is unlikely to be beneficial for reducing overall symptoms of psoriasis. Topical application of inositol 0.25% or 1% for 6 weeks improves overall symptoms when compared with baseline. However, the inositol-containing creams were no more effective than the control cream (104686).
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Trichotillomania.
It is unclear if oral inositol is beneficial for reducing hair pulling.
Details: Preliminary clinical research shows that taking inositol in doses ranging from 6-18 grams daily over a period of 10 weeks is no more effective than placebo in reducing subjective or clinician-documented symptoms of hair pulling in patients with trichotillomania (95089).
More evidence is needed to rate inositol for these uses.
(Read more about INOSITOL)