Dutasteride vs finasteride: which DHT blocker?

Both medicines lower dihydrotestosterone (DHT), the androgen that miniaturises follicles in people who are genetically sensitive to it. Finasteride mainly inhibits type II 5-alpha-reductase. Dutasteride inhibits type I and type II, so typical DHT suppression is greater. That biochemical gap is real; it does not by itself prove dutasteride is the right first prescription for every man. Oral finasteride 1 mg is FDA-approved for male androgenetic alopecia. Dutasteride 0.5 mg is commonly prescribed off-label for hair in the US and EU, and it has a hair-loss indication in Korea and Japan. Comparative trials often report larger hair-count changes on dutasteride, but sample size, dose, and who was enrolled still matter — and the side-effect conversation should be just as direct as the efficacy one.

Sexual side effects (libido, erection, ejaculate volume) are reported with both drugs, usually in a minority of users, and often ease after stopping. Reports of symptoms that linger are real enough to discuss and still debated in how common and how causal they are. Dutasteride stays in the body longer. Both can lower PSA readings, which matters for prostate screening as you age. Pregnancy warning: finasteride and dutasteride can harm a developing male fetus. Do not take them, and do not handle broken tablets, if you are pregnant or may become pregnant. This page is education, not a prescription. A clinician should match the drug to your sex, pregnancy plans, other medicines, and medical history. Sudden patchy, painful, or scarring loss is not a reason to swap DHT blockers — see a dermatologist.

Sources: AGA review (CCID) ↗

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