Vitamin

Inositol

Myo-inositol (cyclohexane-1,2,3,4,5,6-hexol)

Evidence TierBWADA NOT PROHIBITED

tuneTypical Dose

2,000-4,000 mg per day

watchEffect Window

4-12 weeks for PCOS and insulin sensitivity. 2-4 weeks for panic disorder.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Inositol is a cell-signaling molecule, commonly used as myo-inositol and D-chiro-inositol. It is used for insulin sensitivity support, PCOS symptom improvement, and anxiety-related outcomes.

Evidence supports improvements in insulin sensitivity, hormones, and ovulatory outcomes in PCOS more clearly than it supports guaranteed fertility outcomes. Recent higher-level syntheses remain favorable overall, but newer randomized data show that pregnancy-rate gains are not consistent across every infertility design. Higher-dose psychiatric uses remain a separate, less replicated story.

Acts as a second messenger in PI3K/insulin signaling (via inositol phosphoglycans) and serotonin receptor pathways, improving cellular glucose uptake and modulating anxiolytic neurotransmission.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Restores ovulation and improves insulin sensitivity in PCOS (Unfer 2012, Pundir 2018 meta-analyses)
  • Reduces HOMA-IR and testosterone levels in women with PCOS

Secondary Outcomes

  • Reduces panic attack frequency comparably to fluvoxamine at 12-18 g/day (Palatnik 2001)
  • Reduces OCD symptom severity (Y-BOCS) at high doses (Benjamin 1995)

Safety

Contraindications and Interactions

Contraindications

  • Bipolar disorder (especially at psychiatric doses. High doses may destabilize mood)
  • Lactation (caution)

Side effects

  • GI upset (nausea, bloating, diarrhea), dose-dependent, worst at 12-18 g/day
  • Gas and loose stools at moderate doses (2-4 g/day) in a minority of users

Interactions

  • Valproate (Potential/Moderate) - May oppose valproate's therapeutic mechanism involving inositol depletion.
  • Blood-glucose-lowering drugs (Theoretical/Unknown) - Possible additive glucose lowering (including insulin sensitizers such as metformin or thiazolidinediones). Monitor for hypoglycemia symptoms.
  • Blood-glucose-lowering supplements (Theoretical/Unknown) - Possible additive glucose lowering. Monitor.
  • Blood-pressure-lowering drugs (Possible/Minor) - Possible additive blood-pressure lowering in susceptible users.
  • Blood-pressure-lowering supplements (Theoretical/Unknown) - Possible additive blood-pressure lowering.

Avoid if

  • Bipolar disorder at psychiatric doses
  • Lactation considerations

Evidence

Study-level References

inositol-SRC-001RCT
Sourceopen_in_new

Gerli S, et al. "Randomized, double blind placebo-controlled trial: effects of myo-inositol on ovarian function and metabolic factors in women with PCOS." Eur Rev Med Pharmacol Sci. 2007.

Population: Women with Polycystic Ovary Syndrome

Key findings: Myo-inositol significantly increased ovulation frequency and improved weight loss and leptin levels compared to placebo.

Paper content

Myo-inositol significantly increased ovulation frequency and improved weight loss and leptin levels compared to placebo.

inositol-SRC-002RCT Crossover
Sourceopen_in_new

Palatnik A, et al. "Double-blind, controlled, crossover trial of inositol versus fluvoxamine for the treatment of panic disorder." J Clin Psychopharmacol. 2001.

Population: Patients with Panic Disorder

Key findings: Inositol (18g/day) reduced the number of panic attacks per week significantly more than fluvoxamine (an SSRI).

Paper content

Inositol (18g/day) reduced the number of panic attacks per week significantly more than fluvoxamine (an SSRI).

inositol-SRC-003Systematic review and meta-analysis
Sourceopen_in_new

Fitz V, et al. Inositol for polycystic ovary syndrome. A systematic review and meta-analysis to inform the 2023 update of the International Evidence-based PCOS Guidelines. J Clin Endocrinol Metab. 2024;109(6):1630-1655. doi:10.1210/clinem/dgad762. PMID:38163998.

Population: Women with polycystic ovary syndrome

Dose protocol: Guideline-linked systematic review and meta-analysis across 30 PCOS trials.

Key findings: Review found possible benefits for some metabolic and ovulation outcomes, but judged the overall PCOS evidence limited and inconclusive.

Notes: This is the key modernization source because it corrects the older overconfident fertility framing.

Paper content

Guideline-linked review found that inositol may improve some metabolic outcomes and possibly ovulation in PCOS, but the overall evidence base remains limited, uncertain, and not clearly superior to standard care. Myo-inositol generally caused fewer gastrointestinal adverse effects than metformin.

inositol-SRC-004Umbrella review of meta-analyses from randomized controlled trials.
Sourceopen_in_new

Duan M, Yang M, Li C, Wu X, Yin X, Zhu H. Effects of inositol in women with polycystic ovary syndrome: an umbrella review of meta-analyses from randomized controlled trials. Front Endocrinol (Lausanne). 2026. doi:10.3389/fendo.2026.1741509. PMID:41757236.

Population: Women with polycystic ovary syndrome across 13 included meta-analyses.

Dose protocol: Umbrella review of 13 meta-analyses of RCTs evaluating inositol in PCOS.

Key findings: Inositol significantly improved LH, testosterone, SHBG, HOMA-IR, ovulation rate (RR 2.75), and live birth rate (RR 2.29) versus placebo. Effects versus metformin were largely non-significant. Myo-inositol outperformed D-chiro-inositol alone.

Notes: Highest-level evidence synthesis for inositol in PCOS. Confirms hormonal, metabolic, and reproductive benefits over placebo while showing rough equivalence to metformin.

Paper content

This umbrella review synthesized 13 meta-analyses of RCTs evaluating inositol supplementation in women with PCOS. The analysis found that inositol significantly improved hormonal markers (reduced LH and testosterone, increased SHBG), metabolic markers (improved insulin resistance and triglycerides), and reproductive outcomes (live birth rate RR 2.29, ovulation rate approximately 2.75 times controls). Notably, myo-inositol and combination formulations outperformed D-chiro-inositol monotherapy for most outcomes. This is the most comprehensive pooled evidence summary for inositol in PCOS to date and provides useful context for understanding where DCI fits within the broader inositol landscape.

inositol-SRC-005Double-blind randomized controlled trial
Sourceopen_in_new

Mashhadi F, Ghaebi NK, Rakhshandeh H, Khadem-Rezaiyan M, Roudi F, Nematy M, et al. Effects of Ziziphus jujuba, metformin, and myoinositol on pregnancy rates and metabolic parameters in infertile women with PCOS: a randomized controlled trial. J Ovarian Res. 2026;19(1):11. doi:10.1186/s13048-025-01867-0. PMID:41618368.

Population: Infertile women with PCOS.

Dose protocol: Myoinositol 2000 mg/day for 12 weeks in infertile women with PCOS undergoing letrozole induction.

Key findings: Pregnancy occurrence was not significantly higher than placebo in this trial.

Notes: Important corrective source for overconfident fertility framing. It narrows claims without undoing the broader ovulatory and metabolic evidence base.

Paper content

This 2026 PCOS trial is useful because it keeps inositol claims calibrated. Myoinositol did not significantly raise pregnancy occurrence versus placebo in this letrozole-assisted infertility setting, even though inositol remains plausible for metabolic and ovulatory support in broader PCOS evidence. It is a good corrective against overpromising fertility outcomes from inositol alone.

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