PCOS is a hormonal and metabolic condition. It can involve irregular periods, higher androgen levels (which can cause acne or excess hair growth), and insulin resistance. Because insulin resistance plays a role for many women, a lot of PCOS supplement research focuses on blood sugar and metabolic health.
Start with the guideline
The 2023 International Evidence-based Guideline for the Assessment and Management of PCOS, endorsed by major medical societies including ASRM, is the most authoritative summary of what works. We reference it throughout this article.
Inositol: the most studied PCOS supplement
Inositol is a vitamin-like compound involved in insulin signaling. The two forms used in PCOS products are myo-inositol and D-chiro-inositol.
The 2023 international guideline states that inositol in any form "could be considered" in women with PCOS, given its limited harm and potential to improve metabolic measures, but with limited clinical benefits for ovulation, hair growth or weight. The guideline also says specific types, doses or combinations can't yet be recommended because the evidence isn't strong enough.
Research is mixed. A 2023 meta-analysis of 26 trials concluded inositol is effective and safe in PCOS, while a 2022 meta-analysis did not find clinically significant improvements in metabolic or hormonal outcomes with myo-inositol. The fair summary: low risk, possible benefit, set realistic expectations.
Other supplements often used in PCOS
| Supplement | Why it's used | Strength of evidence |
|---|---|---|
| Inositol | Insulin sensitivity, metabolic markers | Moderate, mixed |
| Vitamin D | Deficiency is common in PCOS | Useful if you're deficient |
| Omega-3 fish oil | Triglycerides and inflammation | Limited, mostly metabolic markers |
| N-acetylcysteine (NAC) | Antioxidant, insulin sensitivity | Small studies |
| Prenatal multivitamin with folate | Recommended for anyone trying to conceive | Standard of care before pregnancy |
Vitamin D
Low vitamin D is common in women with PCOS. Supplementing makes sense if blood tests show you're low. Ask your clinician to check your level rather than guessing at a dose.
Omega-3s
Fish oil can lower triglycerides, which are often elevated with insulin resistance. Its effect on PCOS symptoms themselves is less clear.
NAC
NAC has been studied in small trials, sometimes compared with metformin. Results are encouraging but not definitive.
Lifestyle comes first
The guideline emphasizes that healthy eating, regular physical activity and, where appropriate, modest weight loss are first-line management for PCOS. Supplements work best as an addition to these habits and to any medical treatment your clinician recommends, not as a replacement.
Choosing a quality product
- Look for products that list the exact form and dose of inositol on the label.
- Choose brands with third-party testing for purity and potency.
- Powdered inositol is common because effective doses are often several grams per day, which would mean many capsules.
For a deeper dive, download our free PCOS Patient Support Guide and visit our Women's Health Guide.
Talk to your clinician first
This article is for education only and is not medical advice. Check with your healthcare provider before starting a supplement, especially if you are pregnant, nursing, take prescription medication, or have a medical condition.