Loading…
We use essential cookies (authentication, your saved goals/stack) by default. With your permission we'll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Head-to-head evidence comparison — which supplement is right for you?
Inositol and Vitamin D3 are closely matched across evidence, studies, and safety.
Verdict
Probably helps
14 of 21 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
18 of 30 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Inositol and Vitamin D3 have evidence — compare verdict strength side-by-side.
2-4g for general anxiety; 12-18g for OCD/panic
Divided into 2-3 doses, With or without food
Myo-inositol powder (most economical for higher doses)
2000-4000 IU daily
Morning with breakfast
D3 (cholecalciferol) softgel or liquid
4-6 weeks
6-12 weeks
3-6 months
First 1-2 weeks
4-8 weeks
4-8 weeks
2-4 weeks
4-8 weeks
Antenatal dietary supplementation with myo-inositol for preventing gestational diabetes
The Cochrane database of systematic reviews (2023) · Meta analysis · n=1319
For the primary neonatal outcomes, only one study measured the risk of a large-for-gestational-age infant and found myo-inositol was associated with both appreciable benefit and harm (RR 1.40, 95% CI 0.65 to 3.02; 1 study, 234 infants; low-certainty evidence).
Inositol Nutritional Supplementation for the Prevention of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Nutrients (2022) · Meta analysis · n=1321
Pooled results were expressed as relative risk (RR) or mean difference (MD) with a 95% confidence interval (95% CI).
Antioxidants for female subfertility
The Cochrane database of systematic reviews (2020) · Meta analysis · n=7760
Due to the very low-quality of the evidence we are uncertain whether antioxidants improve live birth rate compared with placebo or no treatment/standard treatment (odds ratio (OR) 1.81, 95% confidence interval (CI) 1.36 to 2.43; P < 0.001, I2 = 29%; 13 RCTs, 1227 women).
Vitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and Omega-3 Trial
Nature communications (2025) · Meta analysis · n=5205
Mean body mass index (BMI) was 27.5 kg/m2 (SD = 5.3), with 51% female and 17% Black race/ethnicity.
Vitamin D Supplementation for Patients with Dysmenorrhoea: A Meta-Analysis with Trial Sequential Analysis of Randomised Controlled Trials
Nutrients (2024) · Meta analysis · n=687
TSA revealed that the current RCTs provide sufficient information.
Vitamin D and respiratory tract infections
BMJ (2017) · Meta analysis · n=11321
12% reduction in respiratory infections overall
Based on multiple meta-analyses showing inositol benefits for PCOS including improved menstrual regularity, hormonal parameters, and metabolic markers. Evidence quality varies across studies with some limitations noted in systematic reviews.
Meta-analysis showed 12% overall reduction in respiratory infections, with greater benefits in severely deficient individuals. Daily dosing more effective than bolus. Conservative estimate assumes most users not severely deficient.
AI-estimated from published studies. Interpret as directional guidance.
Both Inositol and Vitamin D3 are closely matched — the best choice depends on your specific health goals.
For metabolic health, Inositol has a higher relevance score (80 vs 55).
No known interactions between Inositol and Vitamin D3 have been documented in our database. However, always consult a healthcare provider before combining supplements.