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Updated: 2026-05-29 · v2.0 · Prof. G. Pkhakadze, MD, MPH, PhDCiteEditorial
📰Read the full Inositol evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.
1
Safe
Inositol
Myo-inositol / D-chiro-inositol
Generally SafeStrongVitamin-Like
RDA
Typical 2–4 g myo-inositol
Target
N/A
Upper limit
No UL; studied up to 18 g
Products
1,014
Dosage by population group — reference
🔗 Best with: D-Chiro-Inositol, Folate, Chromium✅ USP Verified, NSF Contents Certified, ConsumerLab Approved
⚠ PCOS patient — 4 g/day myo-inositol (40:1 with D-chiro) improves ovulation and metabolic parameters [2]
⚠ GDM prevention — 4 g/day from first trimester in high-risk women [2]
⚠ Panic disorder patient intolerant of SSRIs — 12–18 g/day is a reasonable alternative (single RCT) [1]
⚠ Too much D-chiro-inositol can WORSEN ovarian function — maintain 40:1 ratio [2]
⚠ Lithium depletes inositol — supplementation may reduce lithium efficacy [1]
ℹ️ Not obtained from food. Made by the body and widely present in food; there is no established daily dietary target.
🔬 Lab interpreter
Recommended test
No routine monitoring for supplement use
Reference range / target
N/A
When to test
N/A [1].
For PCOS: hormonal panel, HOMA-IR [2]. For GDM: OGTT [2].
Full lab monitoring ↓
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Inositol has two distinct dose-dependent applications: PCOS at 4 g/day (meta-analysis: improved ovulation, insulin sensitivity, testosterone) and panic/OCD at 12–18 g/day (comparable to fluvoxamine). GDM prevention in pregnancy (4 g/day, first trimester) is one of the best-supported pregnancy supplement interventions. The 40:1 myo:D-chiro ratio matters for PCOS [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
WELL-STUDIED. 4 g/day reduces GDM incidence in high-risk women (multiple RCTs). Safe. One of the best pregnancy supplement interventions [2].
👦 Pediatric: See guidance
Limited data. Not routinely recommended [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose

How to take

🍽 Timing: Divided doses (BID or TID) for high-dose psychiatric use. Once or twice daily for PCOS [1] [2].
💊 With food: With or without food. Sweet taste [1].
🚫 Avoid: Lithium-treated patients without physician guidance [1].
2 Which form?
FormBioavailabilityVeganCost
['Myo-inositol powder', 'preferred', 'Sweet taste, dissolves easily. 4 g/day for PCOS; 12–18 g/day for psychiatric [1].']StandardCheck label
['Myo-inositol + D-chiro-inositol (40:1)', 'preferred for PCOS', 'Physiological ratio. Most PCOS trials use this combination [2].']StandardCheck label
['Inositol capsules', '', '500–1,000 mg per capsule (need many for therapeutic dose) [1].']StandardCheck label
3 Common questions
Can inositol treat anxiety as well as SSRIs? ▼
For panic disorder: one crossover RCT found 12–18 g/day comparable to fluvoxamine with fewer side effects [1]. This is a single trial and insufficient to replace SSRIs for most patients, but it is a reasonable option for SSRI-intolerant patients with panic disorder.
Why is the PCOS dose different from the psychiatric dose? ▼
Different mechanisms: PCOS uses the insulin second-messenger pathway (4 g/day saturates this). Psychiatric applications require higher doses to affect serotonin/dopamine signal transduction (12–18 g/day) [1] [2].
Is D-chiro-inositol important? ▼
For PCOS: the 40:1 myo:D-chiro ratio mirrors physiological ovarian ratio. Too much D-chiro-inositol may paradoxically worsen ovarian function. The ratio matters [2].
Can inositol prevent gestational diabetes? ▼
Multiple RCTs show myo-inositol 4 g/day started in the first trimester reduces GDM incidence in high-risk women. One of the few evidence-based pregnancy supplement interventions [2].
4 Clinical evidence

Strong

Second messenger in insulin signaling — well-established biochemistry [1]. HIGH

Moderate

PCOS: meta-analysis showed myo-inositol 4 g/day improved ovulation, reduced testosterone, improved insulin sensitivity and metabolic parameters [2]. Panic disorder: 12–18 g/day was comparable to fluvoxamine in a crossover RCT [1]. OCD: some positive trials as SSRI adjunct [1]. Gestational diabetes prevention: myo-inositol 4 g/day reduced GDM incidence in high-risk women in multiple RCTs [2]. MODERATE

Insufficient

Depression [1]. Bipolar disorder [1]. Diabetic neuropathy [1]. Alzheimer disease [1]. Lithium-induced psoriasis [1]. LOW
5 Safety, toxicity & adverse events

Relative

⚠ Bipolar disorder — may precipitate mania/hypomania
⚠ High doses — gastrointestinal upset
⚠ Pregnancy — myo-inositol is used in pregnancy but should be supervised

🚩 Red flags

● Lithium patient supplementing inositol — may reduce lithium efficacy [1]
● PCOS patient taking pure D-chiro-inositol (not 40:1 ratio) — may worsen ovarian function [2]
6 Interactions

Drug interactions

Lithium Moderate
Mechanism: Lithium depletes inositol (inhibits inositol monophosphatase — its therapeutic mechanism). Exogenous inositol may counteract this. [1]
Effect: Potentially reduced lithium efficacy. [1]
Action: Discuss with psychiatrist before supplementing [1].

Supplement synergies

D-Chiro-Inositol (40:1 ratio) · 110 µg D-chiro per 4 g myo-inositol
Physiological ovarian ratio. The most effective PCOS formulation [2].
Folate · 400 µg folate
Common PCOS co-formulation. Supports fertility [2].
7 Regulatory
United States (FDA): GRAS. Dietary supplement [1].
European Union: Food supplement. Widely used for PCOS in Europe [2].
Italy: Particularly popular for PCOS (major research center for inositol in PCOS) [2].
South Korea: Dietary supplement.
8 US supplement products
1,014
on-market products containing Inositol (NIH DSLD)

Brands carrying Inositol (262)

Click a brand to see its Inositol products.
Or browse all 1,014 products in one list →
9 Frequently paired with
Choline 794 sharedBiotin 763 sharedFolate 732 sharedVitamin C 712 sharedCalcium 711 sharedRiboflavin 710 sharedMagnesium 689 shared
Inositol vs D-Chiro-InositolInositol vs Folate
10 Cite this page
Vancouver: Pkhakadze G. Inositol — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 07]. Available from: https://supplement.ge/ingredients/inositol/
APA 7th: Pkhakadze, G. (2026). Inositol — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/inositol/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Inositol — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/inositol/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG