Are there side effects from finasteride or dutasteride?Updated 3 hours ago

The Finasteride Numbers

The concerns that come up most often are sexual: changes in libido, erectile function, or ejaculation. PCPT, the largest independent long-term trial, tracked 17,313 men for seven years at five times the standard hair-loss dose. Sexual function scores dropped 3.21 points at six months on a 100-point scale, shrinking to 2.11 points by year seven. The researchers concluded the effect "is minimal for most men and should not impact the decision to prescribe or take finasteride." For context, age alone drops that same score by 1.26 points per year: five times the hair-loss dose over seven years does less than three years of normal aging.

In the largest controlled hair-loss trials, the absolute difference over placebo is 1.7 percentage points. That's the honest absolute number, not the relative-risk figure that gets quoted to sound dramatic. Rates also fall over time: by year five of treatment, reported rates are 0.3% or less. PLESS, a separate trial of 3,040 men over four years, found that by years two through four, sexual side-effect rates were identical in the finasteride and placebo groups: 7% in each.

The Dutasteride Numbers

A meta-analysis of 15 randomized controlled trials found dutasteride's sexual dysfunction risk was not statistically significant. Real-world surveillance of more than 700 men taking dutasteride for hair loss found decreased libido at 1.3% and impotence at 1.0%, consistent with the controlled trials.

The Nocebo Effect

A randomized trial in the Journal of Sexual Medicine gave 120 men the same medication at the same dose. One group was told about potential sexual side effects; the other was not. The informed group reported sexual side effects at 43.6%. The uninformed group reported them at 15.3%. Same drug, same dose. The only difference was expectation. That's worth sitting with before letting forum posts shape your decision.

Depression, Suicide, and Post-Finasteride Syndrome

The largest population study on this question covered 2,213,600 patients across five independent studies in European Urology Focus. Researchers found no statistically significant association between finasteride and depression, and none with suicide. In men with no prior depression diagnosis, the hazard ratio for suicide was essentially 1.0.

Post-Finasteride Syndrome is not recognized as a formal diagnosis by the FDA, the WHO, or any major regulatory agency, and the early studies on it recruited exclusively from an advocacy website, which researchers describe as severe selection bias. This does not mean anyone reporting symptoms is making them up. It means the evidence for it as a distinct syndrome does not hold up under controlled scrutiny. If you experience symptoms that concern you, please talk to your Adegen provider.

What About the Topical F and D Variants?

Many people choose a topical variant partly to reduce side-effect risk. That's a reasonable instinct: applying it to the scalp means lower systemic exposure than an oral dose. But "lower" is not "none." Topical finasteride still produces meaningful systemic DHT reduction, roughly a 30–50% drop in serum DHT in published studies. Everything above applies to the topicals too, just at a smaller magnitude: the same concerns, generally less often and less intensely, and the same guidance below.

Irritation, itching, or burning at the scalp is a separate, local issue, not a systemic DHT-blocker side effect. For that, see our guide on scalp irritation.

If You Experience a Side Effect

1. Don't panic. Most side effects from DHT blockers are mild and resolve over time.
2. Don't stop the medication suddenly without talking to your provider.
3. Message your Adegen provider with what you're experiencing, when it started, and how significant it is. They can adjust the dose, switch to a topical, add Tadalafil (which improves blood flow, the opposite mechanism of any theoretical concern from DHT blockers), or recommend a pause.
4. For serious adverse events, anything urgent or severe, contact your physician immediately. For emergencies, call 911.
5. If your concern is serious, persistent, or you feel dismissed at any point, ask for a human agent. We escalate serious side-effect reports to our senior support specialists immediately.