Best Supplements for PCOS: 5 Options Compared Honestly

If you are searching for the best supplements for PCOS, here is the short answer: inositol has the strongest case, vitamin D is worth it if a blood test shows you are low, and berberine, omega-3, and NAC each have some evidence for narrower jobs. None of them replaces medical care, and none of them works in two weeks. This guide compares all five on the same criteria, names a winner, and states the downsides of each.

PCOS runs on insulin resistance for many women, which is why most of the supplements with real research behind them work on that pathway. If that link is new to you, start with insulin resistance explained without the fear, then come back here.

How we compared them

We looked at each option on five things you can actually check.

• Evidence. Randomized trials in women with PCOS, and how carefully they were done.
• What it helps. Cycles, androgens like testosterone, blood sugar, or cholesterol. These are different jobs.
• Dose disclosed. Does a typical label tell you exactly what you are getting per serving?
• Tolerability. Stomach upset, and whether it is easy to take every day for months.
• Safety questions. Drug interactions and anything regulators are still looking at.

A fairness note. A supplement with fewer trials is not proven useless. It has less to show you. We rank on what has been measured and say plainly what has not.

The winner: inositol

Inositol has more randomized trials in PCOS than anything else on the shelf, and the finding that matters most to women is about periods. One review pooled 26 trials covering 1,691 women and found those taking inositol were about 1.8 times more likely to have a regular cycle than women on placebo. It also lowered testosterone, blood sugar, and insulin a little, and it held its own against metformin on most outcomes (Greff, 2023).

Among the options compared head to head in a network analysis of 22 trials, the myo-inositol plus D-chiro-inositol combination stood out for bringing cycles back (Zhao, 2021). Most combination products use a 40 to 1 ratio of the two forms.

The downsides, stated plainly. The most careful review, done to inform the 2023 international PCOS guidelines, went through 30 trials and called the evidence limited and inconclusive. Many of the trials were small and short. That review did find one clear practical win: myo-inositol likely causes fewer stomach side effects than metformin (Fitz, 2024). Results take about three months to judge. Our deep dive on what the inositol for PCOS trials actually show walks through both reviews.

Verdict: the best first supplement to raise with your doctor, especially if irregular cycles are your main concern or metformin has been hard on your stomach.

Runner-up for blood sugar: berberine

Berberine works on a similar cellular pathway to metformin, and it has real PCOS trials. In one trial of 89 women with PCOS and insulin resistance, three months of berberine beat placebo on fasting glucose, insulin resistance, and cholesterol, and beat metformin on waist to hip ratio and several cholesterol measures (Wei, 2012). A pooled analysis of 10 trials found that adding berberine to standard fertility treatment raised ovulation and pregnancy rates (Ha, 2024).

The downsides. In the same network analysis where inositol stood out, berberine was in the conversation but was not the winner for cycles or testosterone (Zhao, 2021). Most trials were small and run in one country. It commonly causes constipation or stomach upset, it interacts with the way your body clears many prescription drugs, and it is not for pregnancy or trying to conceive on your own. Read what the berberine research really says, including the safety questions before you buy it.

Verdict: a reasonable second choice for insulin resistance with your doctor's sign-off. Not a do-it-yourself supplement.

Vitamin D: only if you are actually low

Vitamin D has a surprising amount of PCOS research. Across 10 studies, it lowered insulin resistance, fasting insulin, an inflammation marker, and total testosterone compared with placebo (Wu, 2026). In a review of 12 studies with 849 women, it also improved cycle regularity (Han, 2023).

The catch. A 2026 review of 11 studies found that women with PCOS who were not carrying extra weight had the same vitamin D levels as women without PCOS. The authors suggest low vitamin D in PCOS may track with body weight more than with PCOS itself (Jiang, 2026). So the benefit probably depends on starting low.

Verdict: cheap, well tolerated, and worth it if a blood test shows you are low. Test before you take it, and see how much vitamin D women actually need for dosing basics.

Omega-3: a cholesterol and insulin helper

An umbrella review that graded the strength of evidence across 28 PCOS meta-analyses found fish oil lowered fasting insulin and insulin resistance, and omega-3 lowered triglycerides, both with moderate certainty (Moslehi, 2023). That is a respectable grade for a supplement.

The downsides. The benefits are on blood fats and insulin, not cycles or androgens. If your PCOS shows up mainly as irregular periods, omega-3 is not aimed at that. Fishy burps are the common complaint, and the label should state the milligrams of EPA and DHA, not just total fish oil.

Verdict: a sensible add-on if your cholesterol or triglycerides are high. Not a first pick for cycles.

NAC: interesting, not yet proven

N-acetylcysteine, usually sold as NAC, is an antioxidant that has been tested in PCOS as a gentler alternative to metformin. A review of 18 studies with 2,185 women found it lowered total testosterone and raised FSH, a hormone involved in ovulation, but it did not change follicle count or endometrial thickness (Shahveghar Asl, 2023). A separate review of 11 trials in 869 women found it lowered fasting blood sugar compared with placebo or metformin (Liu, 2023).

The downsides. The effects are small, the trials vary a lot in design, and the two reviews did not agree on every hormone measure. It is a reasonable topic to raise, especially around fertility treatment, where most of the trials were done.

Verdict: promising, with the least settled evidence of the five.

Best supplements for PCOS side by side

• Inositol. Best for: cycles. Evidence: the most trials, mixed quality. Stomach: gentle. Watch for: slow, give it three months.
• Berberine. Best for: insulin resistance and cholesterol. Evidence: moderate, mostly small trials. Stomach: often upset. Watch for: drug interactions, not in pregnancy.
• Vitamin D. Best for: women who test low. Evidence: many trials, benefit likely depends on starting level. Stomach: gentle. Watch for: test first.
• Omega-3. Best for: high triglycerides. Evidence: moderate certainty for insulin and blood fats. Stomach: fishy burps. Watch for: EPA and DHA listed on the label.
• NAC. Best for: a conversation around fertility treatment. Evidence: small and inconsistent. Stomach: usually fine. Watch for: least settled of the five.

Is there a PCOS weight loss supplement that works?

Not in any way that shows up on a scale the way the ads suggest. Inositol lowered body mass index by about half a point compared with placebo across the trials that measured it (Greff, 2023). A network analysis of 41 studies with 2,362 women found carnitine, inositol, and probiotics reduced weight and body mass index compared with placebo, but the authors flagged possible publication bias and called for better trials (Hu, 2023).

The honest ceiling is small. These supplements may help the insulin side of PCOS, which can make weight easier to manage over time, but none of them causes meaningful weight loss on its own. Food, movement, sleep, and the medical options you choose with your doctor still do the heavy lifting, and how PCOS and your gut connect covers the food side gently.

Can you take inositol and berberine together?

People do, and both work on insulin, but there are no good trials of the two combined in PCOS. Stacking supplements with overlapping effects makes it hard to know what is helping and what is causing side effects. A common approach is to start one, give it three months, and judge it before adding anything. Do this with your doctor, especially if you already take metformin or any other medication.

How to choose

• Irregular periods are the main problem: start with inositol.
• Insulin resistance or prediabetes on your blood work: ask about inositol or berberine.
• Vitamin D came back low: correct it, whatever else you do.
• High triglycerides: omega-3 is a reasonable add-on.
• Pregnant or trying to conceive: talk to your doctor before any of these. Several are studied alongside fertility treatment, which is a medical setting, not a shopping list.

Supplements are loosely regulated, so choose products with independent third-party testing and a label that discloses the dose of each ingredient. Skip proprietary PCOS blends that hide the amounts. For more hormone guides written the same way, browse our hormones section.

This article contains no affiliate links. Where our articles do link to products, we may earn a commission. See our disclosure page. This is general information, not medical advice. PCOS care is individual, and supplements can interact with medications. Talk with your doctor before starting any of these, especially if you are pregnant, trying to conceive, or taking prescription medication.

References

• Greff D, Juhász AE, Váncsa S, et al. Inositol is an effective and safe treatment in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Reproductive Biology and Endocrinology. 2023. PMID: 36703143
• Fitz V, Graca S, Mahalingaiah S, 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. Journal of Clinical Endocrinology and Metabolism. 2024. PMID: 38163998
• Zhao H, Xing C, Zhang J, He B. Comparative efficacy of oral insulin sensitizers metformin, thiazolidinediones, inositol, and berberine in improving endocrine and metabolic profiles in women with PCOS: a network meta-analysis. Reproductive Health. 2021. PMID: 34407851
• Wei W, Zhao H, Wang A, et al. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndrome. European Journal of Endocrinology. 2012. PMID: 22019891
• Ha S, Song X. Berberine as adjuvant therapy for treating reduced fertility potential in women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials. Explore. 2024. PMID: 39236662
• Wu, et al. A meta-analysis of the effects of vitamin D supplementation on endocrine metabolic and inflammatory markers in patients with polycystic ovarian syndrome. Medicine (Baltimore). 2026. PMID: 41496027
• Han, et al. Effect of vitamin D supplementation on hormones and menstrual cycle regularization in polycystic ovary syndrome women: a systemic review and meta-analysis. Journal of Obstetrics and Gynaecology Research. 2023. PMID: 37364886
• Jiang M, Wang T, et al. Serum vitamin D levels in non-obese women with polycystic ovary syndrome: a systematic review and meta-analysis. Frontiers in Endocrinology. 2026. PMID: 42381874
• Moslehi, et al. Effects of nutrition on metabolic and endocrine outcomes in women with polycystic ovary syndrome: an umbrella review of meta-analyses of randomized controlled trials. Nutrition Reviews. 2023. PMID: 36099162
• Shahveghar Asl Z, Parastouei K, Eskandari E. The effects of N-acetylcysteine on ovulation and sex hormones profile in women with polycystic ovary syndrome: a systematic review and meta-analysis. British Journal of Nutrition. 2023. PMID: 36597797
• Liu J, Su H, Jin X, Wang L, Huang J. The effects of N-acetylcysteine supplement on metabolic parameters in women with polycystic ovary syndrome: a systematic review and meta-analysis. Frontiers in Nutrition. 2023. PMID: 37841396
• Hu X, Wang W, Su X, et al. Comparison of nutritional supplements in improving glycolipid metabolism and endocrine function in polycystic ovary syndrome: a systematic review and network meta-analysis. PeerJ. 2023. PMID: 38025704