Which PCOS Supplements Have Evidence? A Graded Table

Of every supplement sold for polycystic ovary syndrome, inositol has the most evidence: the integrity-screened review behind the 2023 international guideline included 30 trials of 2,230 women, pooled 19, and found benefit on some blood measures, likely no difference from metformin on reproductive outcomes, and evidence it called limited and inconclusive.^{2, 3} A separate 2023 pooling of 26 trials reported regular cycles 1.79 times as likely as placebo, but on two trials of 118 women at very low certainty; it counted a 2007 trial of 92 women retracted in 2023 and a 2018 trial of 60 women retracted in 2024, which are not counted here.¹ The rest are graded below; berberine is never taken in pregnancy.⁷ PCOS is a GP diagnosis; the NHS now calls it polyendocrine metabolic ovarian syndrome (PMOS), previously PCOS.¹⁵

Evidence at a glance

• Trials: 30 inositol trials, 2,230 women, integrity-screened for the 2023 guideline; 20 vitamin D trials, 1,961 women; 12 berberine trials; 8 NAC trials, 910 women.^{2, 4, 7, 11}
• Largest single trial cited: 70 women, 12 weeks, shatavari against placebo.¹³
• Strongest measured outcome: stomach side effects far less common on myo-inositol than on metformin, odds ratio 0.09, six trials, 382 women, moderate certainty.²
• Not tested: "hormone balance" as a trial outcome; chromium or magnesium given to correct a measured deficiency.

Sources checked on 12 October 2026.

Which PCOS supplements have evidence?

Grades follow trial count, size and quality, and whether the outcome was one a woman can feel.

Nothing on the table has high-quality evidence; the guideline graded every supplement outcome low to moderate.^{2, 3} The cycle and pregnancy outcomes were measured in the inositol, vitamin D, NAC and add-on berberine trials; the rest moved blood markers. How inositol works: what is inositol.

Which is better for PCOS, berberine or inositol?

Inositol: 30 trials of 2,230 women in the guideline review, benefit on some blood measures, regular periods not significantly different from metformin (three trials, 247 women, moderate certainty).^{2, 3} Berberine: 12 trials with lower testosterone and better insulin measures, "no solid evidence" on live birth, the add-on gains in the table, and contraindicated in pregnancy and breastfeeding.^{7, 8} A network meta-analysis of 22 trials found the myo- plus D-chiro-inositol combination better than metformin alone for menstrual recovery, in an indirect comparison with a very wide margin of error; one of its 22 trials is under an expression of concern for its hormone results.¹⁴ Who must avoid berberine: what is berberine and what does it do.

What vitamin am I lacking if I have PCOS?

Possibly none; a blood test settles it. Low vitamin D is common across the UK in winter: the NHS says adults need 10 µg a day and cannot make enough from sunlight between October and early March.¹⁷ Women on metformin can run short of vitamin B12, which the NHS lists among its side effects.¹⁶ Heavy or irregular bleeding can lower iron. The chromium trials used 200 µg as a supplement, not to correct a deficiency.¹⁰ For zinc (does zinc help with PCOS), one placebo-controlled trial of 48 women, 50 mg a day for 8 weeks, measured hirsutism, not deficiency; a 2015 trial of 52 women was placed under a note of concern in 2022 and is not counted here.^{18, 19}

Can I reduce my PCOS fast?

No, and be wary of anything that promises to. PCOS is diagnosed by a GP, usually on two of three features: irregular or absent ovulation, excess androgen, and polycystic ovaries on a scan.³ The guideline puts lifestyle change at the centre, with medicines chosen for the problem at hand: the combined pill for cycles and skin, metformin for insulin resistance, and letrozole or clomifene when ovulation is the goal.^{3, 15} The weight-loss injections, and how to eat on them: food for PCOS.

What is shatavari, and who should not take it?

Shatavari is the root of Asparagus racemosus, an Ayurvedic women's tonic. Its only randomised PCOS trial gave 35 women a standardised root extract and 35 a placebo for 12 weeks: ovarian volume did not differ, follicle count fell, endometrial thickness rose (p = 0.028) and perceived stress fell; hormones, BMI and blood tests did not change.¹³ Not for anyone pregnant, breastfeeding without a doctor's agreement, with an oestrogen-sensitive condition, or under 18.

What do UK inositol sachets contain?

The table is about ingredients, not products. UK PCOS sachets typically combine myo-inositol with minerals and vitamins, sometimes shatavari; the inositol trials used 1 to 4 g of myo-inositol a day, most of them 4 g, so compare the label with that.² Their cautions follow the table: not for under-18s or pregnancy, breastfeeding only under medical supervision, no shatavari with an oestrogen-related condition, and a GP's word first on antidiabetic medicines, because inositol and chromium both moved insulin measures in trials.^{2, 10}

What about pregnancy and trying to conceive?

Tell your GP or fertility clinic about every supplement. Berberine is never taken in pregnancy or while breastfeeding; shatavari is not for pregnancy.⁷ Inositol's pregnancy evidence is uncertain: the Cochrane review's live-birth odds ratio with myo-inositol before IVF was 2.42 (0.75 to 7.83; two trials, 84 women); its search closed in 2018, and the largest IVF trial in its scope, 526 women in 2016, was retracted in 2026.²⁰ Vitamin D at the NHS 10 µg is standard pregnancy advice.¹⁷

The Wellgard women's health guide begins with what causes BV and why it comes back.

What we don't know

• No trial has compared two supplements on this table head to head with live birth as the outcome.
• No trial has measured "hormone balance"; every figure above is a blood test, cycle count or pregnancy rate.
• No trial has tested chromium or magnesium given to correct a measured deficiency.
• No shatavari trial has run beyond 12 weeks; the 42-woman spearmint trial has not been repeated.

Frequently asked questions

What are the top 5 supplements for PCOS?

By the largest review of each: inositol (30 trials), omega-3 (21 studies), vitamin D (20), berberine (12; not in pregnancy) and chromium (10).^{2, 4, 5, 7, 10} "Top" means most studied, not proven.

What is the best supplement for PCOS balance?

"Hormone balance" is not an outcome any trial measured. The measured changes are lower testosterone (inositol, berberine, spearmint), lower insulin resistance (inositol, omega-3, chromium) and, for inositol, regular periods no different from metformin.^{2, 6, 7, 10, 12}

Is shatavari safe to take daily?

In the 12-week trial, daily use produced mild or moderate effects in 11.4% of women against 8.5% on placebo.¹³ Nothing longer has been studied, and the pregnancy and oestrogen-condition exclusions apply every day it is taken.

Sources

1. Greff D, et al. Reproductive Biology and Endocrinology, 2023. Pooled analysis of 26 trials, 1,691 women, no integrity screen; cited only for what this page leaves out. PubMed 36703143.
2. Fitz V, et al. Journal of Clinical Endocrinology and Metabolism, 2024. Systematic review for the 2023 guideline, 30 trials included (19 pooled), 2,230 women, integrity-screened. PubMed 38163998.
3. Teede HJ, et al. Human Reproduction, 2023. International evidence-based PCOS guideline, 254 recommendations. PubMed 37580037.
4. Yang M, et al. Frontiers in Endocrinology, 2023. Pooled analysis of 20 randomised trials, 1,961 women. PubMed 37593349.
5. Melo V, et al. Endocrine Regulations, 2022. Systematic review of 21 clinical studies. PubMed 35180821.
6. Zhao G, et al. Reproductive Biology and Endocrinology, 2025. Network pooled analysis of 79 randomised trials, 5,501 women. PubMed 40611279.
7. Xie L, et al. Evidence-Based Complementary and Alternative Medicine, 2019. Pooled analysis of 12 randomised trials. PubMed 31915452.
8. Ha S, Song X. Explore, 2024. Pooled analysis of 10 randomised trials, 713 women. PubMed 39236662.
9. Tang XL, et al. Journal of Obstetrics and Gynaecology Research, 2018. Pooled analysis of 6 randomised trials, 351 women. PubMed 28929602.
10. Hamsho M, et al. Endocrinología, Diabetes y Nutrición, 2025. Pooled analysis of 10 randomised trials, 683 women. PubMed 41067797.
11. Thakker D, et al. Obstetrics and Gynecology International, 2015. Pooled analysis of 8 randomised trials, 910 women; its only live-birth trial, 60 women, was retracted in 2025. PubMed 25653680.
12. Grant P. Phytotherapy Research, 2010. Randomised trial, 42 women, 30 days. PubMed 19585478.
13. Mhatre Y, et al. Frontiers in Endocrinology, 2026. Randomised double-blind trial, 70 women, 12 weeks. PubMed 41816216.
14. Zhao H, et al. Reproductive Health, 2021. Network pooled analysis of 22 randomised trials, 1,079 women. PubMed 34407851.
15. NHS. Polyendocrine metabolic ovarian syndrome (PMOS). Page last reviewed 30 June 2026. nhs.uk/conditions/polyendocrine-metabolic-ovarian-syndrome-pmos.
16. NHS. Metformin. Page last reviewed 5 August 2026. nhs.uk/medicines/metformin.
17. NHS. Vitamin D. Page last reviewed 3 August 2020 (review overdue). nhs.uk/conditions/vitamins-and-minerals/vitamin-d.
18. Jamilian M, et al. Biological Trace Element Research, 2016. Randomised trial, 48 women, 8 weeks. PubMed 26315303.
19. Note of concern (2022) on a 2015 zinc trial, 52 women; not counted as evidence. PubMed 40872977.
20. Showell MG, et al. Cochrane Database of Systematic Reviews, 2018. Pooled analysis of 13 trials, 1,472 women; search closed July 2018. PubMed 30570133.

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