PCOS and hair

Key takeaways

• PCOS can cause androgen-related hair changes: unwanted facial and body hair (hirsutism), and scalp thinning in a female-pattern distribution, with the crown and part widening and the frontal hairline usually kept, often with oily skin and acne (Carmina 2019; Viveiros 2026).
• Female pattern hair loss alone is not proof of PCOS. The Androgen Excess and PCOS Society report says isolated pattern loss with normal androgens should not be considered a sign of hyperandrogenism, yet every patient with it should be assessed for possible androgen excess (Carmina 2019).
• The treatment ladder is the same as for other female pattern loss, with hormones added. The report advises starting with minoxidil 5% and adding 5-alpha-reductase inhibitors or anti-androgens for severe loss or hyperandrogenism (Carmina 2019).
• Spironolactone is the standard off-label anti-androgen, but PCOS data are thin. A 2026 review of 5 open-label trials found no significant difference between spironolactone (alone or with metformin) and metformin alone on hirsutism score, testosterone or BMI; side effects included menstrual irregularity, polyuria and stomach upset (Viveiros 2026). See spironolactone.
• Pregnancy matters. Anti-androgens and 5-alpha-reductase inhibitors are unsuitable in pregnancy; many hair-loss drugs have little safety data, and some can alter hormone labs or mask PCOS signs during diagnosis (Brinks 2026).
• Magnesium for 10 weeks (64 women) improved quality of life but not alopecia or acne in a 2022 trial (Jaripur 2022).

How it works and how it is checked

PCOS raises circulating androgens and often causes insulin resistance. Hair follicles in genetically sensitive scalp zones miniaturize, while facial and body follicles enlarge (background in DHT and pattern hair loss).

The 2023 international PCOS guideline governs diagnosis and management (Teede 2023). Work-up for suspected androgen excess includes menstrual history, clinical signs and blood tests; the Society report also suggests considering vitamin D, iron, zinc, thyroid hormones and prolactin (Carmina 2019). See iron and ferritin and thyroid and hair.

What the studies show

For female pattern loss generally, a network meta-analysis of 13 trials ranked finasteride 5 mg/day for 24 weeks top on hair density, then topical minoxidil 5% twice daily, then oral minoxidil 1 mg/day (Gupta 2024). The Cochrane review (47 trials, 5,290 participants) found topical minoxidil beneficial but finasteride 1 mg no better than placebo in women (van Zuuren 2016). The conflicting doses and populations are why hormone therapy is a specialist decision.

Hair type notes

• Fine, straight or wavy hair shows a widening part early.
• In curly hair (3A to 4C) crown thinning is masked by volume. In women of African descent consider central centrifugal scarring alopecia and traction too (see CCCA).
• An oily scalp often accompanies androgen excess (see sebum and scalp types).

Bottom line

Thinning plus irregular periods, acne, unwanted hair or weight change is a reason to see a GP, gynaecologist or endocrinologist, not only a salon. Ask for assessment of androgens, thyroid and ferritin, and photograph your part monthly. Minoxidil is the over-the-counter first step (minoxidil); the rest is prescription-only. Do not stop contraception or start anti-androgens without advice, because pregnancy plans change everything. Hair changes take 6 to 12 months on any therapy. See the treatment ladder. Discuss with a doctor.