Herbs and Supplements for PCOS: What Improves Ovulation, Insulin and Androgens
The supplements with the best evidence for PCOS are myo-inositol (ideally with D-chiro-inositol in a 40:1 ratio), berberine and vitamin D, followed by N-acetylcysteine and omega-3. Inositol restores ovulation in roughly 60 to 70 percent of women with PCOS in randomised trials and lowers insulin and testosterone, and berberine improves insulin resistance about as much as metformin in head-to-head studies. These are not fringe remedies: inositol now appears in the 2023 international PCOS guideline as an option, with the caveat that it is weaker than metformin for metabolic outcomes.
PCOS is mostly an insulin and androgen problem. Around 70 percent of women with PCOS have insulin resistance regardless of weight, high insulin drives the ovaries to make more testosterone, and testosterone blocks ovulation and causes acne and hair growth. That is why the supplements that work are mostly insulin sensitisers, and why the herbs with the weakest data are the ones sold for "hormone balance" with no mechanism behind them. Spearmint tea, which does lower free testosterone a little in two small trials, is not in our library, so it gets a mention rather than a ranking.
This guide is for women with a PCOS diagnosis (Rotterdam criteria) or strong suspicion who want evidence-based additions to lifestyle change and, where prescribed, metformin or the pill. See a clinician first if your periods have stopped for more than 3 months, if you are trying to conceive and have not within 12 months (6 months if over 35), if you have rapid-onset hair growth or deepening voice (possible androgen-secreting tumour), or if you have symptoms of diabetes such as thirst and frequent urination. Endometrial protection matters: fewer than four periods a year raises endometrial cancer risk, and no supplement fixes that reliably.
Quick answer
- Myo-inositol (40:1 with D-chiro) — restores ovulation in 60–70% of women and lowers insulin and testosterone; 4 g/day
- Berberine — improves insulin resistance comparably to metformin and lowers androgens; 500 mg three times daily
- Vitamin D — corrects the deficiency found in 67–85% of women with PCOS and improves menstrual regularity when low
- N-acetylcysteine (NAC) — improved ovulation and pregnancy rates with clomiphene in 8 RCTs
- Omega-3 — lowers triglycerides, insulin and testosterone modestly over 12 weeks
- Cinnamon — improved menstrual cycle frequency and insulin resistance in small RCTs
The 10 best herbs and supplements for pcos
Ranked by the strength of human evidence. Strong = multiple trials or a meta-analysis. Moderate = a few small trials. Preliminary = early or animal data.
Myo-inositol (with D-chiro-inositol 40:1)
Strong evidenceInositol is a second messenger for insulin signalling, and women with PCOS have an impaired version of it. A 2018 Cochrane review and a 2023 meta-analysis of 26 RCTs found myo-inositol improved ovulation rates (about 2.3 times more likely than placebo), lowered fasting insulin, HOMA-IR and total testosterone, and raised SHBG. In a 2007 RCT, 4 g/day restored ovulation in 88 percent of women within 16 weeks. Trials comparing it with metformin find similar effects on ovulation and menstrual regularity with far fewer gut side effects; metformin remains better for weight and glucose.
- Key evidence
- 2023 meta-analysis of 26 RCTs on ovulation, insulin and androgens; included as an option in the 2023 International PCOS Guideline
- Studied dose
- 4 g/day myo-inositol split into 2 doses, often combined with 100 mg D-chiro-inositol (40:1), plus 400 mcg folic acid, for at least 3 months
- Best for
- Irregular cycles, anovulation, or trying to conceive; the first thing to try
- Cautions
- Very safe; mild nausea or loose stools at over 12 g/day. Can lower blood sugar with diabetes drugs. Avoid high-dose D-chiro-inositol alone (above about 600 mg/day), which may worsen egg quality.
Berberine
Strong evidenceBerberine activates AMPK, the same pathway as metformin. A 2012 RCT of 89 women with PCOS found 500 mg three times daily matched metformin for reducing insulin resistance and beat it for lowering waist-to-hip ratio, triglycerides and total testosterone over 3 months. A 2021 meta-analysis of 12 RCTs confirmed improvements in HOMA-IR, LDL, triglycerides and testosterone, and one IVF trial found higher pregnancy rates in the berberine group than with metformin. Most trials are Chinese and short, so expect smaller effects in practice.
- Key evidence
- 2012 RCT of berberine vs metformin vs placebo in 89 women with PCOS (Wei et al., European Journal of Endocrinology)
- Studied dose
- 500 mg three times daily with meals (1,500 mg/day), 3–6 months
- Best for
- Insulin resistance, high triglycerides and abdominal weight gain; a metformin alternative for women who cannot tolerate it
- Cautions
- Inhibits CYP3A4 and CYP2D6, raising levels of ciclosporin, some statins, metoprolol and others; additive with diabetes drugs. Do not use in pregnancy or breastfeeding (kernicterus risk in newborns). Constipation or diarrhoea are common.
Vitamin D deficiency is found in 67–85 percent of women with PCOS and tracks with insulin resistance and irregular cycles. A 2019 meta-analysis of 11 RCTs found supplementation lowered total testosterone, fasting glucose and triglycerides, and improved menstrual regularity, with the clearest benefit in women who started deficient. A 2015 RCT of 50,000 IU weekly for 8 weeks improved cycle regularity in two-thirds of participants versus a quarter on placebo. Effects on ovulation and fertility outcomes are less consistent.
- Key evidence
- 2019 meta-analysis of 11 RCTs on metabolic and endocrine outcomes in PCOS
- Studied dose
- 1,000–4,000 IU/day D3 with a fatty meal based on blood level; or 50,000 IU weekly for 8–12 weeks under supervision if deficient
- Best for
- Any woman with PCOS whose 25-OH-D is below 30 ng/mL, which is most
- Cautions
- Test before high doses; above 4,000 IU/day long term can raise calcium. Interacts with thiazide diuretics and digoxin via calcium. Safe in pregnancy at standard doses.
N-acetylcysteine (NAC)
Moderate evidenceNAC improves insulin sensitivity and ovarian response, probably by reducing oxidative stress. A 2015 meta-analysis of 8 RCTs (910 women) found NAC improved ovulation and pregnancy rates compared with placebo when added to clomiphene, and a 2007 RCT of 1,200 mg/day for 5 days found ovulation rose from 17 to 49 percent in clomiphene-resistant women. A 2020 meta-analysis also found NAC was similar to metformin for BMI, insulin and testosterone over 24 weeks, with better tolerability.
- Key evidence
- 2015 meta-analysis of 8 RCTs on ovulation and pregnancy in PCOS (Thakker et al.)
- Studied dose
- 600 mg twice daily to 1,200 mg three times daily (1.2–1.8 g/day), 8–24 weeks; higher doses only when used with ovulation induction
- Best for
- Women trying to conceive, especially if clomiphene alone has not worked
- Cautions
- Can thin blood slightly; caution with warfarin and before surgery. Nausea and sulphur smell are common. May interact with nitroglycerin, causing headaches and low blood pressure. Discuss with your fertility clinician before combining with clomiphene or letrozole.
Omega-3 (EPA and DHA)
Moderate evidenceWomen with PCOS often have high triglycerides and low-grade inflammation, both of which omega-3 addresses. A 2018 meta-analysis of 9 RCTs found omega-3 lowered HOMA-IR, triglycerides, total cholesterol and LDL in PCOS, and a 2013 RCT of 3 g/day for 8 weeks lowered total testosterone and improved menstrual regularity in 47 percent of participants versus 22 percent on placebo. It has no direct effect on ovulation rates.
- Key evidence
- 2018 meta-analysis of 9 RCTs on insulin and lipids in PCOS (Yang et al.)
- Studied dose
- 1–3 g/day combined EPA + DHA with food, 8–12 weeks
- Best for
- PCOS with high triglycerides, fatty liver or cardiometabolic risk
- Cautions
- Mild antiplatelet effect; tell your doctor if you take warfarin or DOACs and stop a week before surgery. Choose purified fish oil in pregnancy. Fishy burps and loose stools at 3 g or more.
Cinnamon improves insulin signalling and the data in PCOS are small but positive. A 2014 RCT of 1.5 g/day for 6 months in 45 women found menstrual cycles increased from 0.8 to 1.6 per 3 months (near-doubling) versus no change on placebo, and a 2007 pilot found 1 g/day for 8 weeks improved insulin resistance. A 2018 RCT of 1.5 g/day for 12 weeks lowered fasting insulin and LDL. No trial has measured pregnancy rates, and effects on testosterone are inconsistent.
- Key evidence
- 2014 RCT of cinnamon 1.5 g/day for 6 months on menstrual cyclicity in 45 women with PCOS (Kort & Lobo)
- Studied dose
- 1–1.5 g/day of cinnamon powder or extract in capsules, 8–24 weeks
- Best for
- Irregular cycles with mild insulin resistance; a cheap add-on to inositol
- Cautions
- Cassia cinnamon contains coumarin, which can stress the liver at over 1 g/day long term; prefer Ceylon (verum) or a coumarin-free extract. Additive with diabetes drugs and may add to anticoagulants. Avoid high doses in pregnancy.
Chromium picolinate
Preliminary evidenceChromium enhances insulin receptor activity. A 2018 meta-analysis of 7 RCTs in PCOS found chromium supplementation lowered fasting insulin and HOMA-IR and raised free testosterone slightly, which is not what you want, while a 2015 RCT of 200 mcg/day for 8 weeks improved insulin markers but did not change hormones. Another small trial found 1,000 mcg/day over 6 months improved menstrual cyclicity similarly to metformin. The evidence is inconsistent and mostly about insulin, not fertility.
- Key evidence
- 2018 meta-analysis of 7 RCTs on metabolic outcomes in PCOS (Fazelian et al.)
- Studied dose
- 200–1,000 mcg/day chromium picolinate, 8–24 weeks
- Best for
- Insulin resistance when inositol or berberine are not tolerated
- Cautions
- Additive with diabetes drugs; rare kidney and liver reports at high doses. Levothyroxine absorption is reduced if taken together; separate by 4 hours. Avoid with kidney disease.
Vitex acts on dopamine receptors in the pituitary to lower prolactin and nudge progesterone, which makes it useful for luteal-phase problems and PMS rather than classic PCOS. A 2019 systematic review found it improved menstrual regularity and lowered prolactin in women with cycle disorders, and a 12-week RCT found it raised progesterone, but there are no RCTs specifically in PCOS showing improved ovulation or testosterone. Women with high LH may do worse, so it suits a narrow subgroup.
- Key evidence
- 2019 systematic review of 17 trials in menstrual disorders and PMS (Rafieian-Kopaei & Movahedi)
- Studied dose
- 20–40 mg/day of a dried fruit extract standardised to 0.5% agnuside, taken in the morning for 3 cycles
- Best for
- PCOS with mildly raised prolactin, PMS or a short luteal phase, not the classic high-androgen picture
- Cautions
- Interacts with dopamine agonists and antagonists (bromocriptine, metoclopramide, antipsychotics) and may reduce the effect of hormonal contraception. Stop once pregnant. Not for women with high LH without monitoring.
Magnesium glycinate
Preliminary evidenceMagnesium is lower in women with PCOS and is needed for insulin signalling. A 2017 RCT of 250 mg/day magnesium plus 220 mg zinc for 12 weeks lowered CRP and improved antioxidant status and hirsutism scores, and a 2020 meta-analysis found magnesium supplementation improved HOMA-IR in people with insulin resistance generally. On its own in PCOS, though, an 8-week trial of 250 mg/day found no significant change in insulin or androgens, so it is a supporting player.
- Key evidence
- 2017 RCT of magnesium plus zinc co-supplementation in 60 women with PCOS (Afshar Ebrahimi et al.)
- Studied dose
- 250–400 mg/day elemental magnesium as glycinate, evening, 8–12 weeks
- Best for
- PCOS with poor sleep, anxiety, cramps or a low-magnesium diet
- Cautions
- Loose stools above 400 mg; reduce in kidney disease. Separate from antibiotics (quinolones, tetracyclines) and bisphosphonates by 2–4 hours. Safe in pregnancy.
Green tea catechins improve insulin sensitivity and may lower androgens. A 2017 RCT of 500 mg green tea extract twice daily for 12 weeks in 60 overweight women with PCOS found greater weight loss, lower fasting insulin and lower free testosterone than placebo, and a 2024 meta-analysis of 5 small trials found reductions in weight and insulin. Trials are few and the weight-loss effect may explain most of the hormone change.
- Key evidence
- 2017 RCT of green tea extract 1,000 mg/day for 12 weeks in 60 women with PCOS (Tehrani et al.)
- Studied dose
- 500 mg twice daily of a decaffeinated extract standardised to EGCG (about 400–500 mg EGCG/day), with food, 12 weeks
- Best for
- Overweight PCOS where weight loss is a goal
- Cautions
- High-dose extracts on an empty stomach have caused liver injury; take with food, keep EGCG under 800 mg/day, and stop if you notice dark urine or jaundice. Reduces iron absorption and interacts with beta-blockers (nadolol). Caffeinated versions add to stimulants.
How to choose
- If your cycles are irregular or you are trying to conceive, start with myo-inositol 4 g/day (40:1 with D-chiro) and folic acid. It is the only supplement here with Strong evidence for ovulation and it is safe to continue into pregnancy.
- If insulin resistance, weight gain or high triglycerides are the main problem and you are not trying to conceive, berberine 1,500 mg/day is the most metformin-like option. Stop it before trying to conceive, as it is unsafe in pregnancy.
- Test vitamin D before anything else: most women with PCOS are deficient, and correcting it improves cycle regularity in RCTs. It stacks with everything on this list.
- If you are on clomiphene or letrozole and not ovulating, ask your fertility clinic about adding NAC 1.2–1.8 g/day, which improved ovulation and pregnancy rates in meta-analysis.
- For acne and unwanted hair, the realistic targets are inositol, berberine and spearmint tea (two cups a day lowered free testosterone in two small 30-day trials; not in our library). None match spironolactone or the combined pill, so manage expectations.
- Keep it simple: inositol plus vitamin D plus one insulin sensitiser is a full stack. Adding vitex, DIM and licorice on top of that is rarely justified and increases interactions.
What to skip
DIM (diindolylmethane)
DIM is sold for "oestrogen dominance", which is not what PCOS is. It has no RCTs in PCOS, it can raise rather than lower androgen activity in some models, and the only human data are in cervical dysplasia and prostate cancer. Leave it out.
Licorice root for androgens
A tiny 2004 study of 9 women found 3.5 g/day licorice lowered testosterone, but licorice raises blood pressure, drops potassium and causes fluid retention with regular use, which outweighs an unreplicated effect. If you want an anti-androgen, ask about spironolactone.
Maca, black cohosh and "hormone balance" blends
None has a controlled trial showing improved ovulation, insulin or testosterone in PCOS. Blends also tend to underdose the ingredients that do work, like inositol, which needs 4 g/day, not 400 mg.
Over-the-counter progesterone cream
It does not induce ovulation or protect the endometrium reliably, and absorption through skin is erratic. If you need progesterone to bring on a period or protect your uterine lining, you need a prescribed dose.
Safety and when to see a clinician
- See a clinician if your periods are absent for more than 3 months, you have fewer than 4 periods a year (endometrial risk), you have not conceived after 12 months of trying, or you develop rapid hair growth, deepening voice or clitoral enlargement, which need investigation rather than supplements.
- Pregnancy: berberine, licorice, green tea extract and vitex should be stopped once you are pregnant or actively trying. Inositol, vitamin D, omega-3, magnesium and folic acid are safe to continue.
- Diabetes drugs: inositol, berberine, cinnamon, chromium, NAC and omega-3 all lower glucose or insulin; combined with metformin or insulin they can cause lows. Monitor and tell your prescriber.
- Berberine interacts with many drugs through CYP3A4 and P-glycoprotein, including ciclosporin, tacrolimus, some statins, metoprolol and certain antidepressants. Check before combining.
- Blood thinners and surgery: omega-3, NAC and cinnamon have mild antiplatelet effects. Stop them a week before surgery and tell your anaesthetist.
- Liver signals: high-dose green tea extract and cassia cinnamon (coumarin) have both caused liver injury. Stop and get liver tests if you notice itching, dark urine or yellow eyes.
What matters as much as any herb
- Weight loss of 5–10 percent, where relevant, restores ovulation in a majority of overweight women with PCOS and lowers testosterone more than any supplement; it is the first-line treatment in every guideline.
- Resistance training two to three times a week improves insulin sensitivity independent of weight loss and lowers androgens in PCOS trials; it is at least as effective as cardio.
- A lower-glycaemic-load diet with protein at every meal reduces insulin spikes; in a 2010 RCT it improved menstrual regularity more than a standard healthy diet with the same calories.
- Sleep and sleep apnoea: PCOS carries a high rate of obstructive sleep apnoea, which worsens insulin resistance. Loud snoring or daytime sleepiness warrants a sleep study.
- Metformin and the combined pill remain the best-evidenced medical options; supplements work best alongside them, not instead of them.
Frequently asked questions
What is the best supplement for PCOS?
Myo-inositol, usually 4 g/day combined with D-chiro-inositol in a 40:1 ratio. It restores ovulation in 60–70 percent of women in trials, lowers insulin and testosterone, and is safe in pregnancy. Berberine is the strongest option for the insulin and weight side of PCOS if you are not trying to conceive.
How long does inositol take to work for PCOS?
Most trials run 12–16 weeks, and that is a fair minimum before judging. Insulin and testosterone markers shift within 8 weeks; menstrual regularity and ovulation typically follow by 3–6 months. Give it at least 3 cycles at the full 4 g/day dose.
Is berberine better than metformin for PCOS?
In head-to-head trials they are roughly equal for insulin resistance, and berberine did slightly better for lipids and waist size with fewer gut side effects. Metformin has far more long-term safety data, works in pregnancy planning and is cheaper. Berberine must be stopped before conception.
Which herbs lower testosterone in PCOS?
Spearmint tea (two cups daily) lowered free testosterone in two small 30-day trials, and inositol, berberine and omega-3 all reduce total testosterone modestly by lowering insulin. Licorice lowers testosterone but raises blood pressure. None match prescription anti-androgens like spironolactone.
Can supplements help me get pregnant with PCOS?
Inositol improves ovulation rates and is used in fertility clinics, and NAC added to clomiphene increased pregnancy rates in a meta-analysis of 8 trials. Correcting vitamin D deficiency also helps. If you have been trying for 12 months (6 if over 35), see a fertility specialist; letrozole remains the most effective ovulation induction drug.
Does cinnamon help PCOS?
Small RCTs found 1.5 g/day roughly doubled menstrual frequency over 6 months and improved insulin resistance. It is cheap and reasonably safe if you use Ceylon cinnamon rather than cassia to avoid coumarin, but it has not been shown to improve pregnancy rates.
Should I take D-chiro-inositol alone?
No. High doses of D-chiro-inositol on its own (above about 600 mg/day) can impair egg quality, and the ovary needs mainly myo-inositol. The 40:1 myo to D-chiro ratio used in most trials reflects the body's own plasma ratio and is the safest choice.
References
- Showell MG et al.. Inositol for subfertile women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews (2018)View source
- Teede HJ et al.. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Journal of Clinical Endocrinology and Metabolism (2023)View source
- Wei W 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)View source
- Thakker D et al.. N-acetylcysteine for polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled clinical trials. Obstetrics and Gynecology International (2015)
- Kort DH, Lobo RA. Preliminary evidence that cinnamon improves menstrual cyclicity in women with polycystic ovary syndrome: a randomized controlled trial. American Journal of Obstetrics and Gynecology (2014)View source
- Yang K et al.. Effects of omega-3 fatty acid supplementation on metabolic parameters in women with polycystic ovary syndrome: a systematic review and meta-analysis. Reproductive Biology and Endocrinology (2018)
- Łagowska K, Bajerska J, Jamka M. Vitamin D supplementation for women with polycystic ovary syndrome: a systematic review and meta-analysis. Nutrients (2018)
- Genazzani AD et al.. Myo-inositol administration positively affects hyperinsulinemia and hormonal parameters in overweight patients with polycystic ovary syndrome. Gynecological Endocrinology (2008)
- Grant P. Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome: a randomized controlled trial. Phytotherapy Research (2010)View source
- Polycystic ovary syndrome (PCOS). NHSView source
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Ask about pcosThis guide is educational and is not medical advice. Herbs and supplements can interact with prescription medicines and are not regulated like drugs. Talk with a clinician or pharmacist before starting anything new, especially if you are pregnant, breastfeeding, have a chronic condition, or take medication.