Spearmint Tea for PCOS: The Two Trials, the Dose, and the Honest Timeline

Does Spearmint Tea Lower Testosterone in PCOS?

Two cups a day dropped both free and total testosterone within 30 days in the only randomized trial to test spearmint tea specifically in women with PCOS-related hirsutism. That trial, run across two UK centres in 42 women, is the whole reason spearmint tea shows up on PCOS lists at all. LH and FSH also rose. On the blood work, spearmint tea did what it was supposed to do.

What it did not do, in that same 30 days, was change how much hair was actually growing.

The Two Trials Behind the Spearmint Tea Claim

There are exactly two published human trials, both small, both Turkish-influenced in origin, and they do not agree on which testosterone measure moved.

Read the last column of both rows together and the honest picture appears: spearmint tea reliably moves at least one androgen number on a blood panel. Neither trial demonstrated that this translates into less visible hair growth in the time it tested. The earlier of the two, a 5-day trial in 21 women — 12 with PCOS and 9 with hirsutism from other causes, only checked hormones, not hair, so it cannot speak to hirsutism at all. Grant’s is the only trial that actually measured hirsutism itself with a clinical scoring tool, and on that measure the result was flat.

Set against the trial base behind the pharmacological options in the 2023 international PCOS guideline — combined hormonal contraception, anti-androgen medication — two small trials, one running only five days, is a considerably thinner evidence base. That does not make spearmint tea useless. It does mean the honest label for it is “weakly promising,” not “proven.”

How Long Does Spearmint Tea Take to Work for Facial Hair?

Thirty days was long enough to lower blood testosterone in the Grant trial, but not long enough to move the score that reflects actual hair growth. That gap is not a fluke of one study — it is how hair biology works. A hair follicle that is already in an active growth phase does not stop and shed on the day a hormone level changes; it finishes the cycle it is already in. Trimming or shaving does not reset that clock either. So even a real, sustained drop in androgen exposure shows up in visible hair only after months of consistently lower levels, not after four weeks of tea.

No trial has followed spearmint tea and hirsutism scores past 30 days, so there is no study that can put a specific week-count on “when it works.” The realistic, unhedged answer is: expect the earliest hormone changes within a month, and do not expect to judge hair growth on anything shorter than three to six months of consistent daily use — and even then, without a trial to confirm it, that is an inference from hair-cycle timing, not a proven result.

Spearmint Tea Side Effects

Neither trial reported a formal side-effect table, and neither described participants leaving the spearmint arm because of an adverse reaction. One of the 42 participants in Grant’s trial did not complete the study, but the paper does not say why, so that single dropout should not be read as evidence of a side effect.

Spearmint is a common food and beverage ingredient with a long history of use as tea, and caffeine-free. The one effect worth knowing about mint teas generally — not specific to PCOS, and not something either trial reported — is that menthol can relax the muscle that keeps stomach acid down, which is why some people with reflux or heartburn find mint teas make it worse. That is a general food-safety note, not a finding from either spearmint-PCOS trial. Neither trial reported on use during pregnancy or breastfeeding, so there is no trial-based safety data either way for that situation.

Dose Variability: Tea Is Not a Standardised Product

Spearmint tea is a food, not a regulated drug, and that changes what “the dose” even means. Both trials used a specific steeped tea bag, brewed twice daily under study conditions — that is the only preparation with any trial evidence behind it. A store-bought spearmint tea bag brewed for a different length of time, a loose-leaf infusion, or a spearmint supplement capsule sold alongside the tea are not proven equivalent to what either trial tested, because the concentration of active compound was never measured or standardised across brands. If you are trying to replicate the trial conditions as closely as possible, that means two cups a day of a plain steeped spearmint tea — not a multi-herb blend, and not an assumption that a capsule delivers the same dose a cup does.

What This Won’t Help

Spearmint tea has a plausible, weakly-tested effect on one axis: circulating androgens. It has no trial evidence for anything beyond that, and among the options covered across this site’s supplements and medications section, it clearly will not help in these situations:

• Hirsutism that isn’t androgen-driven. Some hair growth patterns have other causes; a tea that lowers testosterone has nothing to act on if testosterone isn’t the driver.
• Anyone expecting a fast, dramatic change. The only trial that measured hair growth directly found no significant change in 30 days.
• A replacement for medical anti-androgen treatment. Nothing here competes with the effect size of options covered in hirsutism and PCOS, and it should not delay a conversation about those if hirsutism is significant to you.
• Cycle regulation or fertility. Neither trial measured ovulation, cycle length, or pregnancy outcomes. Spearmint tea has no trial evidence for either.

You may also see PCOS written as polyendocrine metabolic ovarian syndrome (PMOS), after a 2026 global consensus of more than 50 organisations renamed it. Nothing about either spearmint trial changes under the new name — this article uses PCOS because that is still what people search.

Two other botanicals get asked about alongside spearmint for PCOS. Vitex (chasteberry) works through a completely different mechanism — prolactin, not testosterone — and has almost no PCOS-specific trial evidence at all. DIM (diindolylmethane) has none. If you’re comparing options, the evidence-ranked supplements guide puts all of them against inositol, berberine and vitamin D, where the trial evidence is considerably stronger.

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