Bicalutamide

What it is

Bicalutamide is a non-steroidal drug that blocks the androgen receptor. Its labelled use is metastatic prostate cancer (50 mg, together with an LHRH analogue). No regulator has approved it for hair loss, so use in women is off-label, and it is prescription-only. A review article (not a trial) describes it as having no diuretic effect, not crossing the blood-brain barrier and having little effect on LH, which is why some prefer it to spironolactone. Carvalho 2022

How it works

It competes with testosterone and DHT at the androgen receptor, blocking the signal in the follicle rather than lowering DHT. That is a different route from finasteride and dutasteride. See DHT and pattern hair loss.

What the studies show

• Versus spironolactone (204 women, 24 weeks, double-blind, one centre in India): frontal hair count rose 5.05 vs 3.13/cm² in favour of bicalutamide 50 mg (difference 1.92, p<0.001), vertex 6.32 vs 3.06, with greater shaft diameter. The authors state there was no significant between-group difference in clinical endpoints. Adverse events were 11.7% vs 18.6%. Jha 2026
• 24-month retrospective cohort (187 women, Madrid): both drugs improved the Sinclair grade by an average of 0.5; at least one grade of improvement occurred in 54.4% on spironolactone vs 37.3% on bicalutamide (p = 0.030), and bicalutamide caused more laboratory abnormalities. Gil-Redondo 2026
• A man with resistant hair loss (case report): regrowth was reported alongside breast enlargement and pain, lost libido, erectile dysfunction and raised liver enzymes, and the drug was stopped. The authors say it should not be taken as support for use in men. Martinez Coronado 2026
• The two 2026 comparisons disagree partly because they measure different things: hair counts under magnification versus a clinical grade.

How it's used in studies

• Oral: 50 mg a day for 24 weeks in the one randomised trial. Jha 2026
• Scalp injections (mesotherapy): appear only in letters and small series, with no controlled data we could verify.

Side effects and safety

• Liver: the prostate-cancer prescribing information warns of severe liver injury and fatal liver failure, and advises liver tests before starting, regularly for the first four months, then periodically.
• Pregnancy: contraindicated in women who are or may become pregnant (risk of fetal harm), so reliable contraception is essential if it is used.
• Men: breast enlargement and breast pain are listed effects, and the case report above adds lost libido and erectile dysfunction. It is not a sensible hair treatment for men.
• Long term: gynecologic-cancer safety of antiandrogens other than spironolactone in women is described as uncertain. Seyed Jafari 2024

Bottom line

The evidence is limited: one short randomised trial and retrospective series from specialist clinics, with conflicting head-to-head results against spironolactone. The authors of the trial themselves found no significant clinical difference, so it is unclear whether the extra hair count becomes visible. For women it is a second-line option after spironolactone and minoxidil, prescribed with contraception and liver tests. Best dose and long-term liver safety in healthy women are unresolved. It is not for men and not for self-medication. Discuss with a doctor.