In trials, sexual side effects from finasteride 1mg occur in a small minority of men — only slightly above placebo — and usually resolve after stopping. Persistent symptoms are reported but uncommon and debated, so weigh benefits and risks with a clinician.
How common are the side effects?
The side effects that worry men most are sexual (reduced libido, erectile difficulty, ejaculation or semen-volume changes) and, less commonly, mood changes such as low mood or depressive symptoms.
In the controlled clinical trials of finasteride 1mg for hair loss, sexual side effects were reported by only a small percentage of men — roughly 4% versus about 2% on placebo — meaning the rate was only modestly higher than placebo. For most men who experience them, the effects are mild and reverse after stopping the drug. Importantly, men who are explicitly warned about sexual side effects report them more often than men who are not told — a documented nocebo effect — which complicates interpreting real-world rates.
Mood-related effects are reported less frequently. Regulators have noted depression and, rarely, suicidal ideation in post-marketing reports, so labels mention them, but a clear causal link at a population level remains debated and the absolute numbers appear low.
Post-finasteride syndrome and persistence
A subset of men describe persistent sexual, mood, or cognitive symptoms continuing after stopping — sometimes called post-finasteride syndrome. The evidence here is genuinely uncertain: it rests largely on case reports and self-reported registries rather than controlled data, the frequency is unclear, and not all experts agree it is a distinct entity. The honest summary is that persistent effects are uncommon but reported, and the science is still unsettled.
Managing side effects and when to stop
If you develop bothersome symptoms, the first step is to talk to your prescriber rather than quitting abruptly or pushing through silently. Options a clinician may consider include reassessing whether symptoms are truly drug-related, trialing a lower or less frequent dose, switching to topical minoxidil alone, or stopping finasteride to see whether symptoms resolve.
Most sexual side effects ease within weeks to a few months of stopping. Stop and seek prompt medical care for any thoughts of self-harm, significant depression, breast lumps or discharge, or a severe allergic reaction (such as swelling of the lips, tongue, or throat). Tell any doctor you take finasteride before a PSA test, since it lowers the reading by roughly half. This is general information, not personal medical advice — decisions about starting, continuing, or stopping should be made with your clinician.
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Are finasteride's sexual side effects permanent?
For the large majority of men, no — they are uncommon to begin with and typically resolve after stopping the medication. A small number report persistent symptoms after discontinuation, but this is uncommon and the evidence is limited and debated. Discuss any concerns with your prescriber.
Does finasteride cause depression?
Mood changes including depression have been reported and appear on product labels, but a clear causal link at a population level is not established and the absolute risk appears low. If you notice low mood, anxiety, or any thoughts of self-harm, stop and seek medical help promptly.
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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