The PCOS Supplements That Are Actually Worth Your Money

So you have just been diagnosed, you have opened seventeen tabs, and somewhere around tab nine a woman with excellent lighting told you that a $90 powder fixed her cycle in a fortnight. Welcome. I have been exactly where you are.

In my first year I spent about £600 on supplements with gorgeous packaging and roughly the same amount of human evidence as a scented candle. Some of it helped. Most of it made expensive urine.

So here is the version I wish someone had handed me. Everything below has been studied in actual humans with PCOS, at a stated dose, and I have graded each one by how strong that evidence really is — not by how convincing the label was.

1. Inositol (myo + D-chiro, 40:1)

If PCOS supplements had a homecoming queen, it would be inositol. Multiple randomised trials have looked at what it does to insulin sensitivity, ovulation rates and androgen levels, and the results have been consistent enough that several clinical guidelines now mention it by name.

The detail nobody puts on the front of the tub is the ratio. Your blood carries myo-inositol and D-chiro-inositol at roughly 40 to 1, and the trials that found benefits mostly used that same ratio: about 4,000 mg myo alongside 100 mg D-chiro, split into two doses.

Give it twelve weeks. Inositol works on the timescale of a menstrual cycle, not a long weekend.

The full breakdown of the ratio is here.

2. Vitamin D3 (with K2)

Deficiency is significantly more common if you have PCOS, and low levels track with worse insulin resistance and less regular cycles. This is one of the very few supplements where you genuinely should not guess — you should test.

• Ask for a 25-hydroxyvitamin D test before you buy anything
• Most deficiency protocols land between 2,000–4,000 IU a day
• Take it with a meal containing fat, since it is fat-soluble
• The K2 is there to send calcium to your bones rather than your arteries

3. Omega-3 fatty acids

Meta-analyses in PCOS populations show lower triglycerides and modest improvements in insulin sensitivity markers. Solid, unglamorous, works. Get the triglyceride form rather than ethyl ester, and ignore the enormous number on the front of the bottle — turn it over and find the actual EPA and DHA figures.

4. Spearmint extract

Two small randomised trials found reduced free testosterone after 30 days of twice-daily spearmint tea. Small studies, short duration — so file this under promising rather than proven. That said: it is inexpensive, low-risk, and it is a hot drink. The bar for “worth trying” is lower when the intervention is tea.

5. N-acetylcysteine (NAC)

NAC has gone head-to-head with metformin in several ovulation-induction trials, and some found broadly comparable results. Doses were typically 1,200–1,800 mg daily. Evidence quality is genuinely mixed, and this is the one on the list I would most want a clinician weighing in on.

The four I would skip

1. Proprietary “hormone balance” blends. If the label will not tell you the doses, you cannot know whether anything is at a studied level.
2. High-dose biotin. It interferes with thyroid and hormone lab assays — meaning it can mess up the very tests you are trying to get answers from.
3. Detox teas. A diuretic and a laxative in a beautiful pouch. Your liver has been detoxing you for free this whole time.
4. High-dose D-chiro on its own. Some evidence suggests too much may impair egg quality. The 40:1 ratio is not marketing.

If you only remember two things: start with inositol at the 40:1 ratio, and get your vitamin D tested.

Everything else is fine-tuning on top of blood sugar, sleep and strength training — all of which are, annoyingly, still free. The full comparison table scores every product on evidence, dose, purity testing and cost per day.

Some links on this site are affiliate links. We may earn a commission at no extra cost to you. Rankings are decided before any affiliate programme is applied, and no brand can pay for placement.