Hirsutism and PCOS: Why It Happens and What Actually Reduces It

Why androgens turn fine hair into coarse hair

A hair follicle does not know it is growing “excess” hair. It is responding to a signal.

Androgens — mainly testosterone and its more potent skin metabolite, dihydrotestosterone (DHT) — bind receptors in the follicle and convert soft, unpigmented vellus hair into thick, pigmented terminal hair, in the same pattern typically seen in male body-hair distribution: upper lip, chin, chest, lower abdomen, inner thighs. The follicle’s sensitivity to androgens, not just the amount of androgen circulating, decides how visible the change is — which is why two women with identical testosterone levels can have very different amounts of hair.

Polycystic ovary syndrome and idiopathic hyperandrogenism together cause more than 85% of hirsutism cases in women of reproductive age, per a 2019 clinical review in American Family Physician. Rarer causes — androgen-secreting tumours, congenital adrenal hyperplasia, Cushing’s syndrome — need ruling out when hair growth is sudden, rapid, or comes with a deepening voice or clitoral enlargement.

Note: in May 2026, PCOS was renamed polyendocrine metabolic ovarian syndrome, or PMOS, by a global consensus of more than 50 organisations. Same condition, same androgen mechanism behind hirsutism — only the label on the diagnosis changed. This article uses PCOS, since that is still the term most readers search.

How hirsutism is actually measured

A modified Ferriman-Gallwey score of 8 or higher defines hirsutism in Black and white women assessed in the US and UK, but that threshold is not universal. The Endocrine Society’s clinical practice guideline recommends adjusting the cutoff by population — lower thresholds are appropriate in East Asian women, who grow visibly less terminal hair at the same androgen level, and higher baseline growth is normal in women of Mediterranean, Middle Eastern and South Asian descent. A clinician scoring nine body sites against photographic standards, not a mirror check at home, is the only way to get a number that means anything.

What actually reduces it

Every effective option falls into one of two categories: slow down what the follicle produces, or physically remove what is already there. Nothing in the first category works before a full hair growth cycle has passed.

Option	How it works	Time to see change
Combined oral contraceptive	Suppresses ovarian androgen production, raises SHBG so less testosterone is free	6+ months minimum
Anti-androgen (e.g. spironolactone)	Blocks the androgen receptor at the follicle; added if the pill alone is not enough	6+ months, added after a 6-month pill trial
Eflornithine cream	Inhibits an enzyme (ODC) the follicle needs to build the hair shaft; facial use only	4–8 weeks for initial change, continues improving to 24 weeks
Laser or electrolysis	Damages the follicle directly with heat or electrical current	Immediate per session; several sessions needed for lasting reduction

The 2023 international PCOS guideline recommends a combined oral contraceptive as first-line pharmacologic treatment, with an anti-androgen added after roughly six months if the response is inadequate — never as a starting point alone, since anti-androgens carry a feminisation risk to a male fetus and need reliable contraception alongside them. Direct hair removal is recommended as an adjunct at any point, because it is the only option that changes what you see this week rather than in six months.

Each option comes with practical trade-offs worth knowing before you start:

• Combined oral contraceptive. Contraindicated with uncontrolled high blood pressure, a history of blood clots, migraine with aura, or smoking over 35. Also treats the irregular cycles most PCOS phenotypes have alongside hirsutism.
• Spironolactone. Requires a baseline and follow-up potassium check, especially alongside ACE inhibitors or NSAIDs. Not safe in pregnancy, which is the practical reason it is paired with contraception rather than prescribed alone.
• Eflornithine cream. Mild stinging, burning or acne-like breakouts at the application site are the most common side effects, reported more often than with the vehicle cream alone in trials.
• Laser. Works best when there is strong contrast between dark hair and light skin. A long-pulsed Nd:YAG laser is the safer choice for darker skin tones; the wrong wavelength can burn or scar. Electrolysis works on any hair or skin colour, including grey and blonde hair laser cannot target, but treats one follicle at a time.

What the eflornithine trial actually found

Eflornithine cream is the one topical option with FDA approval specifically for facial hirsutism, and it is the treatment most likely to show a change inside two months.

In two identical 24-week randomised, double-blind trials of women with facial hirsutism, treatment success — a physician rating of “clear/almost clear” or “marked improvement” — was reached by 24.4% and 44% of women using eflornithine cream in the two trials, compared with 4.3% and 13% on the vehicle cream alone. Both differences were statistically significant. Effects reversed within about eight weeks of stopping the cream, because it manages hair growth rather than the androgen signal driving it.

Two things worth unlearning first

Shaving does not make hair grow back thicker, darker, or faster. A razor cuts the shaft, not the follicle, and the blunt tip left behind only feels coarser until it grows past the skin’s surface again. The follicle’s output is set by the androgen signal reaching it, not by whether you shaved last week.

Plucking and waxing pull the whole hair, root included, so regrowth takes longer than shaving. But repeated plucking in the same follicle over years can trigger local inflammation and, in some people, scarring or a compensatory increase in nearby follicle activity — a reasonable trade to make for a wedding, a poor one to run for a decade on the same patch of skin.

If your hirsutism runs with insulin resistance

Hyperinsulinemia pushes ovarian theca cells to make more androgen and lowers the liver’s output of SHBG, the protein that keeps testosterone bound and inactive. Less SHBG means more free testosterone reaching the follicle — one route among several that link insulin resistance to visible PCOS symptoms.

That does not mean an insulin-sensitising drug is a hirsutism treatment. Metformin’s effect on hirsutism specifically is weak and inconsistent across trials — useful for the metabolic picture, not a substitute for the pill, an anti-androgen, or direct hair removal when hirsutism itself is the problem you are treating. If your pattern is insulin-resistant, expect metformin to help other things sooner than it helps your chin.

When this needs a doctor sooner rather than later

Hirsutism that develops gradually over years, alongside irregular cycles, fits the ordinary PCOS picture and can be worked through with your GP or a gynaecologist.

Elevated androgens also show up as other visible signs worth checking together, and facial hair specifically has its own management details covered in chin and jawline hair.

Your next step

Book a Ferriman-Gallwey assessment with your GP or gynaecologist before starting anything, so you have a real baseline number to measure against in six months. Then pick one hormonal option and one direct-removal option to run at the same time, rather than waiting to see if the first one works alone.