Both lower DHT to treat pattern hair loss, but they differ in reach. Finasteride blocks only type-II 5-alpha-reductase, while dutasteride blocks both type-I and type-II, suppressing DHT more strongly. Dutasteride is therefore more potent, but that does not mean it is better for everyone.
Regulation matters too. Dutasteride is approved for hair loss in Korea and Japan but is off-label in the US and EU. It has a longer half-life, so it lingers in the body, and its safety profile (including sexual side-effects) is reported as broadly similar to finasteride.
Both drugs can cause birth defects in a male fetus, so anyone who is or may become pregnant must avoid taking or handling them. Whether you need stronger suppression, and how to weigh the longer half-life and side-effects, varies a lot between individuals — decide with a clinician.
Sources: AGA review (CCID) ↗
FAQ
Is dutasteride simply better?
It suppresses DHT more strongly, but "better" is hard to claim. It has a longer half-life, is off-label in the US/EU, and effects and side-effects vary by person. Many people start with finasteride and discuss dutasteride with a clinician only if the response is insufficient.
Can I switch from finasteride to dutasteride?
A switch may be considered when the response is inadequate, but that is a prescription change requiring clinical judgment. Do not switch on your own — talk to a dermatologist.
Which has more side-effects?
Reported rates of sexual side-effects are broadly similar, but dutasteride’s longer half-life means it persists longer after stopping. Assess your personal risk with a clinician.
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⚠️ When to see a doctor — don’t self-treat
- Sudden patchy or circular bald spots
- Redness, scaling, pus, pain or itch (possible scarring alopecia — treat urgently)
- Broken hairs or rapid loss
- Loss with body-wide signs (weight loss, fatigue, cycle changes, acne, extra hair)
- Loss right after a new medication
- Any hair loss in a child