Finasteride: The Benefits, the Side-Effect Numbers, No Scare and No Hype

What it does

Finasteride blocks the enzyme that converts testosterone into DHT in the body. At the 1 mg hair dose, DHT levels fall by roughly 60-70%. Since DHT is what slowly shrinks sensitive follicles in genetic hair loss, lowering it slows the loss and, in many men, thickens existing miniaturised hairs. It protects better than it regrows: the men who benefit most are those who start while they still have hair to save.

How well it works

In the large multi-year trials on 1 mg finasteride, about 9 in 10 men on the medicine either kept their hair or gained visible density over 2-5 years, compared with progressive loss in the placebo group. Crown and mid-scalp respond best; the front hairline responds less. It is a slow medicine — judge it at 12 months, not 12 weeks — and like minoxidil, its benefit lasts only while you take it.

Sexual side effects: the actual numbers

In the controlled trials, decreased libido was reported by about 1.8% of men on finasteride versus 1.3% on placebo; erectile difficulty about 1.3% versus 0.7%; reduced ejaculate volume about 0.8% versus 0.4%. So the excess risk over placebo is small — around 1 extra case per 100-200 users — but it is real, and these effects usually reversed after stopping. There are also reports of effects persisting in a small number of men after stopping; this is debated in the medical literature and is a genuine reason to discuss it with a doctor before starting, not a reason for panic or for dismissal.

Other things to know

Finasteride can lower PSA, a prostate screening marker, so any doctor checking your prostate later must know you take it. It should never be taken by women who are or may become pregnant, and the tablets should not be crushed or handled by them. Some men report mood changes; if you have a history of depression, raise it with your doctor first. The medicine is prescription-only in India for a reason — it changes hormone pathways, which is not a casual experiment.

The sensible way to think about it

Start with a confirmed diagnosis: is your loss actually androgenetic alopecia, and how fast is it moving? A dermatologist can assess this, sometimes with photos or a scalp examination over two visits. If you start, use the prescribed dose, take baseline photos, and review at 6 and 12 months with the same photos. Do not self-start from a friend’s strip, do not double the dose hoping for faster results, and do not combine or swap medicines based on forum advice.

Common questions

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