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Myo-Inositol

Myo-inositol is a cyclitol; human studies show benefits in gestational diabetes, insulin resistance and PCOS, mostly with no difference compared with metformin.

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We evaluated 259 human studies on Myo-inositol, including 91 randomised controlled trials and 60 meta-analyses or systematic reviews; the controlled studies include 17,286 participants in total. As of 9 October 2026.

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1. What Is Myo-Inositol? Occurrence, Origin and Forms

Myo-inositol is a ring-shaped sugar alcohol (a cyclitol) with six hydroxyl groups and one of several stereoisomers of inositol. It occurs in plant foods and is also formed in the human body, among other things as a building block of membrane lipids. As a dietary supplement it is usually taken as a powder or in capsules, often in connection with questions of hormonal balance, fertility and metabolism.

Myo-inositol is found in fruit, nuts, grains and legumes; in the body it is part of phosphatidylinositol in cell membranes and takes part in signalling within the cell. It is studied mainly in questions of fertility, pregnancy and metabolism.

For the supplement market myo-inositol is offered as a single substance, usually as a powder or in capsules. Studies use both pure myo-inositol and mixtures, for example with D-chiro-inositol or with folic acid.

Forms and Preparations Studied

  • Myo-inositol as a single substance (powder, capsules, tablets)
  • Myo-inositol together with D-chiro-inositol (a mixture)
  • Myo-inositol together with folic acid (a mixture)
  • Myo-inositol in combination with other dietary supplement ingredients (a mixture)

Not covered on this page:

  • D-chiro-inositol as a single substance: a different stereoisomer of inositol, not the same as myo-inositol.
  • Inositol hexaphosphate (phytic acid) and inositol nicotinate: other compounds with their own behaviour.
  • Other sugar alcohols and cyclitols such as sorbitol, xylitol or scyllo-inositol: substances in their own right.

2. What Does Myo-Inositol Do? Results by Area

AreaResult in controlled studiesStrength of evidenceStudiesParticipants
Metabolism and insulin actionmixedhigh28 meta-analyses · 43 controlled · 38 other3,475
Polycystic ovary syndromemixedhigh16 meta-analyses · 25 controlled · 50 other1,648
Fertility and conceptionmixedhigh7 meta-analyses · 22 controlled · 34 other1,774
Anxiety and panicmostly improvedmoderate1 meta-analyses · 1 controlled · 4 other60
Other investigationsmostly improvedhigh19 meta-analyses · 22 controlled · 26 other2,915

How to read the table: counted are human studies whose results concern the area. “High” means at least one meta-analysis and two controlled studies showing improvement, or at least three controlled studies of which three quarters show improvement, with at least 300 participants in total. “Moderate” means at least two controlled studies showing improvement, as a majority, or one meta-analysis alongside controlled studies. “Low” means one controlled study showing improvement. Where an area has no controlled study, the strength of evidence is at most “low” (result “reviews only” or “observational data only”). Everything else is “unclear”. A study counts as showing improvement when at least half of its outcomes in this area improved. Reviews of combination products do not count as meta-analyses; results that only describe side effects or shares of users do not count as an effect. The same study is counted only once.

3. What the Studies Show in Detail

Myo-Inositol, Metabolism and Insulin Action: Human Studies

For metabolism and insulin action, myo-inositol and other inositol forms lowered insulin resistance, fasting insulin and fasting glucose more than placebo in several meta-analyses 11624. Triglycerides, total and LDL cholesterol also fell 162454, and compared with metformin triglycerides fell more 28. In pregnant women, the two-hour values in the glucose tolerance test were more favourable than in the control groups 52932484950. Several of these meta-analyses combine myo-inositol with other inositol forms 121624. Myo-inositol plus D-chiro-inositol lowered HOMA-IR more than metformin 19; in pregnancy, a low-dose mixture of both showed no difference from the control 14. Compared with metformin, meta-analyses in PCOS found no difference in fasting insulin, fasting glucose and HOMA index 1735. In a network meta-analysis, none of the treatments, including myo-inositol, lowered HOMA-IR 39. One meta-analysis rates the certainty for insulin resistance and blood lipids as moderate to high, with a high risk of bias in many studies 24; what dose and treatment duration are optimal remains open.

StudyDesign · participantsPreparation · dose · duration · comparisonResult
1 Wang et al. 2025meta-analysis · 30,133 participantsMyo-inositol as a dietary supplement; vs. other dietary supplements or controlInsulin sensitivity (HOMA-IR): improved (SMD = -0.81)
3 Shi et al. 2026meta-analysis · 10,262 participantsInositol (form not specified); vs. Standard controlFasting blood glucose: improved (SMD = -0.42, 95% CI: -0.66, -0.18)
4 Chan et al. 2021meta-analysis · 9,443 participantsmyo-inositol supplementation (4 studies); vs. placebo or controlsurrogate markers of glycemic control, lipid profile, inflammation, oxidative stress: improved
5 Wang et al. 2025meta-analysis · 9,018 participantsMyo-inositol supplementation; vs. Control/placeboIncidence of gestational diabetes: improved (RR: 0.37; 95% CI: 0.32-0.42); Fasting blood glucose: improved (SMD: -1.31 mg/dL; 95%CI: -1.83 to -0.79); Glucose tolerance test at 1 hour: improved (SMD: -2.63 mg/dL; 95%CI: -3.87 to -1.40)
6 Poyatos-León et al. 2026meta-analysis · 4,765 participantsMyo-inositol supplementation; vs. Placebo or standard careRisk of gestational diabetes mellitus: improved (44% risk reduction)
11 Greff et al. 2023meta-analysis · 1,795 participantsInositol/myoinositol supplement; 2-4 g myoinositol; from first trimester; vs. PlaceboFasting, 1-h, and 2-h OGTT glucose levels: improved (significantly decreased); Insulin need: improved (RR = 0.29, CI: 0.13-0.68)
12 Greff et al. 2023meta-analysis · 1,691 participantsInositols (myo-inositol or mixtures, not specified); vs. Placebo or metforminGlucose: improved (MD = -3.14; CI: -5.75; -0.54); AUC insulin: improved (MD = -2081.05, CI: -2745.32; -1416.78)
14 Wei et al. 2022meta-analysis · 1,321 participantsMyo-inositol (MI) nutritional supplementation; 4 g MI/day; 1.1 g MI/day plus 27.6 mg DCI/day; vs. Control groupIncidence of GDM: improved (RR = 0.30, 95% CI (0.18, 0.49), p < 0.00001); Fasting-glucose OGTT: improved (MD = −4.20, 95% CI (−5.87, −2.54), p < 0.00001); 1-h OGTT glucose: improved (MD = −8.75, 95% CI (−12.42, −5.08), p < 0.00001)

Further studies in this area: 16 17 18 22 24 28 29 30 32 34 35 36 38 39 40 47 48 49 50 52 53 54 55 67 70 71 72 73 74 77 79 80 81 83 84 85 87 89 90 91 92 95 97 98 99 100 101 102 103 104 105 106 107 109 110 111 113 114 116 119 120 122 124 125 127 128 133 135 138 139 141 143 144 145 146 147 148 149 150 151 153 154 155 158 160 163 164 168 176 180 187 191 193 194 196 198 199 200 202 204 205

Myo-Inositol and Polycystic Ovary Syndrome: Human Studies

In women with polycystic ovary syndrome, inositol preparations lowered testosterone more strongly than placebo in several meta-analyses 121633. SHBG also rose in several meta-analyses 1121633. Weight and BMI fell more strongly in meta-analyses than with placebo 912, and a regular cycle was more frequent 12. In two randomized studies against metformin, the cycle improved similarly in both groups 91100. Compared with metformin, meta-analyses found no difference in testosterone and SHBG 2835. One meta-analysis found no improvement in testosterone, SHBG and BMI 18, another no confirmed effect on total testosterone 30. For the LH/FSH ratio, one meta-analysis found no difference from metformin 17, another no improvement in LH, FSH and estradiol 18. A network meta-analysis found more frequent menstruations and a lower total testosterone for myo-inositol plus D-chiro-inositol than with metformin 19. A meta-analysis on myo- and D-chiro-inositol in PCOS fertility treatment found a higher pregnancy rate as well as a lower antral follicle count and anti-Müllerian hormone levels 41. The data situation is extensive but heterogeneous: The studies differ in the form (pure myo-inositol or mixtures), in the comparator preparation (placebo, metformin, folic acid, oral contraceptives) and in the duration. It remains open which dose and which mixture is most suitable for which patient group.

StudyDesign · participantsPreparation · dose · duration · comparisonResult
1 Wang et al. 2025meta-analysis · 30,133 participantsMyo-inositol as a dietary supplement; vs. other dietary supplements or controlSHBG levels: improved (SMD = 9.65)
7 Unanyan et al. 2022meta-analysis · 4,668 participantsMyo-inositol, metformin or myo-inositol + metformin; vs. Placebo, no treatment or metforminOHSS (metformin vs. placebo): improved (RR = 0.34, 95% CI: 0.17 to 0.69, p = 0.003)
9 Hu et al. 2023meta-analysis · 2,362 participantsNutritional supplements, including inositol; vs. Placebo and other nutritional supplementsBody weight and body mass index (BMI): improved (reduced body weight and body mass index (BMI) compared to placebo); Fasting blood glucose, fasting insulin, HOMA-IR, QUICKI, triglycerides, total cholesterol, LDL-C, HDL-C, testosterone, SHBG, CRP: unclear (No significant differences were observed in high-density lipoprotein cholesterol (HDL-C), total testosterone (TT), sex-hormone binding globulin (SHBG), and C-reactive protein (CRP) between nutritional supplements and placebo.)
10 Lin et al. 2024meta-analysis · 1,827 participantsMyo-inositol (network meta-analysis); vs. Controls, metformin, anti-obesity agentsOHSS risk: improved
12 Greff et al. 2023meta-analysis · 1,691 participantsInositols (myo-inositol or mixtures, not specified); vs. Placebo or metforminRegular menstrual cycle: improved (1.79); BMI: improved (MD = -0.45; CI: -0.89; -0.02); Free testosterone: improved (MD = -0,41, CI: -0.69; -0.13)
16 Zhang et al. 2021meta-analysis · 1,291 participantsInositols (oral nutritional agents); vs. Placebo/other nutraceuticals (CoQ10, vitamin E, vitamin D)Total testosterone (TT): improved; SHBG: improved; BMI: improved
17 Fatima et al. 2023meta-analysis · 1,088 participantsMyo-inositol (MI) vs. metformin (MET); vs. MetforminLH/FSH ratio: no difference (SMD = 0.20, 95% CI: - 0.24 to 0.64, p = 0.37)
18 Jethaliya et al. 2022meta-analysis · 1,083 participantsMyo-inositol supplementation; vs. Folic acid (7 trials), metformin (8), oral contraceptives (2)body mass index: no difference (No significant improvement); waist-to-hip ratio: no difference (No significant improvement); LH: no difference (No significant improvement)

Further studies in this area: 21 27 28 30 33 34 35 39 43 45 46 51 55 56 57 67 74 78 79 81 87 88 89 90 91 96 100 101 102 106 109 111 114 118 121 124 125 127 128 129 135 136 141 143 145 147 149 150 151 152 153 154 155 159 160 163 165 167 168 169 171 172 173 175 180 181 182 183 184 185 187 190 191 193 194 197 200 201 202 203 204 205 209

Myo-Inositol, Fertility and Conception: Human Studies

In women undergoing fertility treatment with IVF or ICSI, the clinical pregnancy rate was higher with inositol in a meta-analysis, as was the proportion of high-quality embryos 23. One meta-analysis found more mature eggs and a higher fertilization rate with myo-inositol 21; two others found no higher pregnancy rate 1026. In PCOS before IVF, myo-inositol in a randomized controlled trial resulted in a higher clinical pregnancy rate than metformin 79. Compared with D-chiro-inositol, myo-inositol in a randomized trial produced more mature eggs and top embryos 82. The studies mostly report pregnancy rates; whether more children are also born with myo-inositol is still open.

StudyDesign · participantsPreparation · dose · duration · comparisonResult
7 Unanyan et al. 2022meta-analysis · 4,668 participantsMyo-inositol, metformin or myo-inositol + metformin; vs. Placebo, no treatment or metforminclinical pregnancy rate (inositol vs. no treatment): no difference (RR = 1.37, 95% CI: 0.79 to 2.38, p = 0.26); clinical pregnancy rate (inositol vs. metformin): improved (RR = 1.52, 95% CI: 1.05 to 2.18, p = 0.03); clinical pregnancy rate (metformin vs. placebo): improved (RR = 1.30, 95% CI: 1.12 to 1.50, p = 0.0004)
10 Lin et al. 2024meta-analysis · 1,827 participantsMyo-inositol (network meta-analysis); vs. Controls, metformin, anti-obesity agentspregnancy outcomes: no difference; gonadotropin duration: improved (SMD = -1.21, 95% CI -2.03 to -0.38)
13 Showell et al. 2018systematic review · 1,472 participantsOral inositol supplementation (myo-inositol, partly with D-chiro-inositol); vs. Placebo, no/standard treatment, melatonin, metformin, clomiphene, D-chiro-inositolLive birth rate (IVF, vs standard): unclear (OR 2.42, 95% CI 0.75 to 7.83; P = 0.14); Miscarriage rate (vs standard): improved (OR 0.40, 95% CI 0.19 to 0.86; P = 0.02); Multiple pregnancy rate (vs standard): no difference (OR 1.04, 95% CI 0.63 to 1.71; P = 0.89)
20 Mendoza et al. 2017meta-analysis · 1,019 participantsMyo-inositol (MYO), d-chiro-inositol (DCI), or both; any dose; any duration; vs. ovulation-inducing agent aloneoocyte quality: no difference (OR 2.2051; 95% CI 0.8260 to 5.8868); embryo quality: no difference (OR 1.6231, 95% CI 0.3926 to 6.7097); pregnancy rate: no difference (OR 1.2832, 95% CI 0.8692 to 1.8944)
21 Zhang et al. 2025meta-analysis · 981 participantsMyo-inositol supplementation; vs. Control group without myo-inositolMetaphase II oocyte rate: improved (OR 1.55, 95% CI 1.04-2.31, P=0.03); Metaphase II oocyte rate in POR: no difference (OR 0.97, 95% CI 0.35-2.68, P=0.95); Fertilization rate: improved (OR 1.62, 95% CI 1.21-2.16, P<0.01)
23 Zheng et al. 2017meta-analysis · 935 participantsMyo-inositol supplement; vs. Control without myo-inositolClinical pregnancy rate: improved (95% confidence interval (CI), 1.04-1.96; P = .03); Abortion rate: improved (95% CI, 0.08-0.50; P = .0006); Grade 1 embryos proportion: improved (95% CI, 1.10-2.74; P = .02)
26 Pivazyan et al. 2025meta-analysis · 820 participantsMyo-inositol (form/dose not reported in abstract); vs. Control group without myo-inositolNumber of retrieved oocytes: improved (MD = 0.41, 95% CI: 0.05-0.77, p = 0.02); Number of oocytes in poor ovarian responders: no difference (MD = 0.50, 95% CI: 0.57-1.58, p = 0.36); Miscarriage rate: no difference (RRs = 0.81, 95% CI: 0.20-3.32, p = 0.77)
27 Laganà et al. 2018systematic review · 812 participantsoral myo-inositol, partly with D-chiro-inositol; vs. no treatment or D-chiro-inositolgonadotropin amount: improved (p < 0.00001); length of ovarian stimulation: improved (p = 0.0007); gonadotropin amount in non-PCOS: improved (p = 0.02)

Further studies in this area: 51 57 67 73 75 78 79 82 86 90 94 99 108 114 115 118 119 120 123 125 126 129 130 131 133 134 135 140 145 146 147 159 160 161 162 163 164 168 169 174 175 177 181 183 184 186 189 190 191 192 193 195 200 207 209

Myo-Inositol, Anxiety and Panic: Human Studies

For anxiety and panic, a systematic review of complementary treatments found limited evidence of an effect of inositol in panic disorder and obsessive-compulsive disorder 58. A randomized controlled trial in 60 women with PCOS found greater improvements in depression, anxiety and stress scores with myo-inositol than with metformin 95. The evidence is preliminary: the study involved women with PCOS, not people with anxiety disorders; studies in panic and obsessive-compulsive disorder are still pending.

StudyDesign · participantsPreparation · dose · duration · comparisonResult
58 Jorm et al. 2004systematic reviewInositol (stereoisomer not specified); vs. other complementary and self-help treatmentsevidence of effectiveness in panic disorder and obsessive-compulsive disorder: improved (more limited evidence)
95 Jamilian et al. 2018randomised controlled · 60 participantsmyo-inositol versus metformin; 12 weeks; vs. metformin group (n=30)Depression Anxiety and Stress Scale scores: improved (-3.9 ± 6.4 vs. -0.9 ± 1.9, p = 0.01)
156 Song et al. 2026case-control studynone; measurement of myo-inositol in dorsal anterior cingulate cortex; vs. anorexia nervosa group vs. healthy controlsanxiety-to-eat (HED and LED): worsened; myo-inositol in dACC: worsened; association of myo-inositol with anxiety-to-eat for HED foods: improved
164 Baboun et al. 2026reviewMyo-inositol (oral, partly topical)mood and sleep: improved
166 Derkaczew et al. 2026reviewMyo-inositol (also scyllo-inositol, D-chiro-inositol)Anxiolytic effect of inositol stereoisomers: unclear
178 Concerto et al. 2023reviewInositol; vs. Monotherapy or add-on to conventional drugsTreatment of panic disorders: improved

Myo-Inositol: Further Outcomes in Studies

In pregnancy, gestational diabetes occurred less often with myo-inositol than in the control groups in several meta-analyses 3411252950. Pregnancy-induced hypertension and preterm births also occurred less often in several meta-analyses 11152550, but not in another 6. A Cochrane review rates the certainty of these findings as low to very low 15. Birth weight was lower in one meta-analysis 32, and showed no difference in others 293653. For caesarean section, gestational age at birth and neonatal hypoglycaemia, there were predominantly no differences 5153136. In autoimmune thyroiditis, myo-inositol in addition to selenium lowered TSH and TgAb more than selenium alone in meta-analyses, but not TPOAb, T3 and T4 374244. An umbrella meta-analysis on inositol in pregnancy found gestational diabetes, insulin requirement and preterm births less often 40. Most data come from pregnancy studies, predominantly from Italy; studies in other populations and with long-term data are still pending 15.

StudyDesign · participantsPreparation · dose · duration · comparisonResult
2 Tang et al. 2022meta-analysis · 16,545 participantsInositol supplementation (form not specified); vs. Placebo and physical activity, diet, probiotics, mixed interventionIncidence of gestational diabetes: no difference
3 Shi et al. 2026meta-analysis · 10,262 participantsInositol (form not specified); vs. Standard controlIncidence of gestational diabetes: improved (RR = 0.50, 95% CI: 0.37, 0.68)
4 Chan et al. 2021meta-analysis · 9,443 participantsmyo-inositol supplementation (4 studies); vs. placebo or controlrisk of gestational diabetes: improved (RR 0.34, 95% CI 0.20, 0.58)
5 Wang et al. 2025meta-analysis · 9,018 participantsMyo-inositol supplementation; vs. Control/placeboRisk of preterm birth: improved (RR: 0.37; 95%CI: 0.28-0.47); Pregnancy-induced hypertension: improved (RR: 0.34; 95%CI: 0.25-0.47); Cesarean section rates: no difference (RR: 0.82; 95%CI: 0.71-0.94)
6 Poyatos-León et al. 2026meta-analysis · 4,765 participantsMyo-inositol supplementation; vs. Placebo or standard careHypertensive disorders and cesarean delivery: no difference; Macrosomia, preterm birth, neonatal hypoglycemia: no difference
10 Lin et al. 2024meta-analysis · 1,827 participantsMyo-inositol (network meta-analysis); vs. Controls, metformin, anti-obesity agentsside effects (OR = 0.23, 95% CI 0.06-0.83)
11 Greff et al. 2023meta-analysis · 1,795 participantsInositol/myoinositol supplement; 2-4 g myoinositol; from first trimester; vs. PlaceboIncidence of GDM: improved (RR = 0.42, CI: 0.26-0.67); Preeclampsia or gestational hypertension: improved (RR = 0.38, CI: 0.2-0.71); Preterm birth: improved (RR = 0.44, CI: 0.22-0.88)
14 Wei et al. 2022meta-analysis · 1,321 participantsMyo-inositol (MI) nutritional supplementation; 4 g MI/day; 1.1 g MI/day plus 27.6 mg DCI/day; vs. Control groupIncidence of preterm delivery: improved; Neonatal hypoglycemia: improved

Further studies in this area: 15 22 25 29 32 35 36 37 38 40 42 48 49 50 53 62 66 68 69 70 76 77 80 84 85 92 93 95 98 104 105 112 113 116 117 119 122 127 132 133 137 139 142 148 157 158 164 170 171 176 178 179 187 188 196 198 203 206 208

4. How Is Myo-Inositol Dosed? Preparation, Dose and Duration in Studies

The studies used predominantly pure myo-inositol as powder, capsules or tablets. In addition, mixtures with D-chiro-inositol, folic acid, selenium or probiotics as well as combinations with metformin were tested. The doses and treatment durations differ between the studies and are given in the table.

Preparation or formDoseDurationStudy
Myo-inositol plus folic acid2 × 2000 mg myo-inositol + 2 × 200 µg folic acid daily; IVF group B 4000 mg + 400 µg daily2 to 3 months, mean use 10.2 weeks; IVF group B 2 months before protocol59
Supplement with myo-inositol, probiotics and micronutrients—up to 12 months60
Myo-inositol, probiotics, and micronutrients vs. standard micronutrient supplement—from preconception and throughout pregnancy61
Myo-inositol 40 mg/kg or placebo40 mg/kg every 12 hours, initially intravenous, then enteralup to 10 weeks62
Myo-inositol, probiotics and enriched micronutrients—preconception to 6 months post-delivery63
myo-inositol-containing supplement from preconception—from preconception to 28 weeks' gestation64
Supplement with myo-inositol, probiotics and micronutrients vs standard micronutrient—preconception to birth, follow-up to 2 years65
Myo-inositol 2 g with 0.2 mg folic acid per sachet2 g myo-inositol plus 0.2 mg folic acid twice dailyuntil delivery66
Myoinositol plus letrozole—3 months follow-up67
2 g myo-inositol plus 200 µg folic acid2 g myo-inositol + 200 µg folic acid dailyuntil three weeks after delivery68
myo-inositol 2 g plus 200 µg folic acid2 g myo-inositol twice dailyfrom first trimester to delivery69
myo-inositol 2 g plus 200 micrograms folic acid twice daily versus placebo (200 micrograms folic acid twice daily)2 g myo-inositol + 200 micrograms folic acid twice dailyfrom first trimester to delivery70
Myo-inositol plus folic acid vs. folic acid alone4000 mg MI and 400 mcg folic acid dailyuntil 26-28 weeks of gestation71
2 g myo-inositol powder or placebo, both with 200 µg folic acid2 g twice daily until deliveryuntil delivery72
Myo-inositol (capsule/tablet) vs. metformin, Ziziphus jujuba, placebo2000 mg myo-inositol daily12 weeks73

5. Is Myo-Inositol Safe? Side Effects in Studies

Myo-inositol was well tolerated in meta-analyses and a review and caused side effects less often than metformin 283546. In a large randomized controlled trial in very premature infants, myo-inositol did not lower the risk of severe retinopathy or death 62. Mortality was higher than with placebo; the study was terminated early 62. Details on the reported side effects are shown in the table.

StudyReported side effects
6 Poyatos-León et al. 2026No significant differences in secondary maternal and neonatal outcomes
7 Unanyan et al. 2022OHSS lower with metformin vs. placebo (RR = 0.34)
8 Shang et al. 2024antioxidants described as safe
10 Lin et al. 2024Myo-inositol with fewer side effects than controls (OR 0.23)
12 Greff et al. 2023Inositol safe, no specific adverse events reported
13 Showell et al. 2018Uncertain, poorly reported
14 Wei et al. 2022no difference for 1.1 g MI + DCI; safety reported
15 Motuhifonua et al. 2023Not reported
19 Zhao et al. 2021not reported for myo-inositol
22 Vitagliano et al. 2019No adverse effects reported
25 Factor et al. 2023No adverse effects noted
28 Zhang et al. 2022Myo-inositol reduced adverse events (RR=0.14, 95% CI 0.08-0.24, p<0.00001)

6. What Remains Open: Limits of the Evidence

  • Which dose and treatment duration is most suitable for which concern remains open.
  • For combination preparations, the contribution of myo-inositol cannot be separated from that of the other components.
  • Many studies are small and short; the comparison conditions (placebo, metformin, folic acid, D-chiro-inositol) differ greatly.
  • Most data come from pregnancy and PCOS populations; other groups are less studied.
  • Larger controlled studies on myo-inositol in anxiety disorders are still pending.

7. Bottom Line: What Is Established About Myo-Inositol

Myo-inositol is a cyclitol that occurs in foods and is formed in the body. Human studies investigate it predominantly as a pure substance in powder, capsule or tablet form, and also as a mixture with D-chiro-inositol, folic acid or other dietary supplements. The evidence base is extensive for metabolism and insulin action, PCOS, fertility treatment and pregnancy, and rests on controlled studies and meta-analyses. Positive findings stand alongside results showing no difference, and with mixed preparations the contribution of myo-inositol cannot be isolated.

Frequently Asked Questions

How well has Myo-inositol been studied in humans?

We evaluated 259 human studies on Myo-inositol, including 91 randomised controlled trials and 60 meta-analyses or systematic reviews; the controlled studies include 17,286 participants in total. As of 9 October 2026.

Does Myo-inositol help with metabolism and insulin action? What the studies show

We evaluated 28 meta-analyses or systematic reviews, 43 controlled studies and 38 further studies; the controlled studies include 3,475 participants in total. Result of the controlled studies: mixed. Strength of evidence under our published rules: high. Sources: 1345

Does Myo-inositol help with polycystic ovary syndrome? What the studies show

We evaluated 16 meta-analyses or systematic reviews, 25 controlled studies and 50 further studies; the controlled studies include 1,648 participants in total. Result of the controlled studies: mixed. Strength of evidence under our published rules: high. Sources: 17910

Does Myo-inositol help with fertility and conception? What the studies show

We evaluated 7 meta-analyses or systematic reviews, 22 controlled studies and 34 further studies; the controlled studies include 1,774 participants in total. Result of the controlled studies: mixed. Strength of evidence under our published rules: high. Sources: 7101320

Does Myo-inositol help with anxiety and panic? What the studies show

We evaluated one meta-analysis or systematic review, one controlled study and 4 further studies; the controlled studies include 60 participants in total. Result of the controlled studies: mostly improved. Strength of evidence under our published rules: moderate. Sources: 5895156164

What is myo-inositol?

Myo-inositol is a ring-shaped sugar alcohol, a cyclitol, and one of several stereoisomers of inositol. It occurs in plant foods and is also formed in the human body, among other things as a building block of phosphatidylinositol in membrane lipids. As a dietary supplement, it is mostly used in powder or capsule form.

Which forms were investigated in the studies?

Pure myo-inositol as powder, capsules or tablets was investigated, as were mixtures with D-chiro-inositol, with folic acid and with other dietary supplements such as selenium or probiotics. The doses and dosage forms differ between the studies and are given in the table. For combination preparations, the contribution of myo-inositol cannot be separated from that of the other components.

Do the studies show benefits in PCOS?

In women with polycystic ovary syndrome, inositol preparations lowered testosterone more than placebo in several meta-analyses and raised SHBG 121633; compared with metformin, no difference was confirmed 2835. A regular cycle was more common with inositol than with placebo 12; in two randomized studies against metformin, the cycle improved similarly in both groups 91100.

How well tolerated is myo-inositol?

Myo-inositol was well tolerated in meta-analyses and a review and caused side effects less often than metformin 283546. In a large randomized controlled trial in very premature infants, myo-inositol did not lower the risk of severe retinopathy or death 62. Mortality was higher than with placebo; the study was terminated early 62.

What should be considered with combination preparations?

Mixtures contain, in addition to myo-inositol, another substance, such as D-chiro-inositol, folic acid or selenium. A network meta-analysis found more frequent menstruations and a lower total testosterone for myo-inositol plus D-chiro-inositol than with metformin 19. A meta-analysis on myo- and D-chiro-inositol in PCOS fertility treatment found a higher pregnancy rate as well as a lower antral follicle count and anti-Müllerian hormone levels 41. Myo-inositol in addition to selenium lowered TSH and TgAb more strongly in autoimmune thyroiditis than selenium alone, but not TPOAb, T3 and T4 374244.

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International Health Research · https://ih-research.com/en/knowledge/myo-inositol/ · Last updated: 2026-10-15