Does finasteride cause sexual side effects?

Yes, based on clinical trial data. A meta-analysis of 15 trials found men on finasteride 1mg were 66% more likely to report sexual dysfunction than men on placebo, with nearly double the risk of erectile dysfunction. About 2 extra men per 100 were affected compared to placebo.

How common is erectile dysfunction with finasteride?

In pooled trial data, erectile dysfunction was nearly twice as common in men on finasteride vs placebo, which was statistically significant. The absolute difference was roughly 2 extra cases per 100 men compared to placebo.

Does finasteride affect sex drive?

Reduced sex drive was more common on finasteride than placebo in clinical trials, but the difference did not reach statistical significance on its own. It is listed as a known side effect on the product label.

Are finasteride sexual side effects permanent?

For most men, no. Clinical data suggests side effects resolve after stopping in the majority of cases. However, a subset of men report persistent symptoms, and the FDA added this possibility to the product label in 2022.

Should I stop taking finasteride if I get sexual side effects?

That is a decision to make with your prescribing doctor. Clinical data suggests most side effects resolve after stopping. Contact your doctor rather than stopping abruptly without medical guidance.

Does finasteride affect testosterone?

No significant change in testosterone has been found in clinical trials. Finasteride blocks the conversion of testosterone into DHT but does not reduce testosterone itself. Levels typically remain within the normal range or may rise slightly.

Finasteride Sexual Side Effects: What Research Shows

Q: What is post-finasteride syndrome?

Post-finasteride syndrome refers to persistent sexual, mood, and cognitive symptoms some men report after stopping finasteride. It was listed by the NIH as a rare disease in 2019. The condition is debated in the medical literature and no confirmed treatment exists.

Last updated: Apr 20, 2026Fact CheckOral FinasterideBased on 3 studies

This is a research-based fact check, not medical advice. The findings summarized here come from peer-reviewed studies and are presented without added opinions. Consult a certified healthcare practitioner before making any treatment decision.

Verdict

Yes, finasteride 1mg increases the risk of sexual side effects compared to placebo. A meta-analysis of 15 controlled trials (4,495 men) found men on finasteride were 66% more likely to report any sexual dysfunction and nearly twice as likely to report erectile dysfunction (Lee 2019). In absolute terms, 5 in every 100 men on finasteride reported a sexual side effect, compared to 3 in every 100 on placebo.

Key takeaways

Sexual side effects are statistically confirmed: finasteride 1mg was linked to a 66% higher risk of any sexual dysfunction vs placebo across 15 controlled trials.
Erectile dysfunction had the strongest signal: men on finasteride were nearly twice as likely to report it vs placebo.
In raw numbers, the absolute risk is small: 5 in every 100 men on finasteride reported a sexual side effect, vs 3 in every 100 on placebo.
Reduced sex drive and ejaculation problems trended higher but did not reach statistical significance on their own.
Most side effects resolve after stopping, but a small number of men report persistent symptoms after discontinuation.
The FDA updated the finasteride label in 2022 to include suicidal ideation as a potential side effect.

In 2022, the FDA required finasteride manufacturers to add suicidal ideation to the product label as a potential side effect. In 2019, post-finasteride syndrome was listed in the NIH database of rare diseases.

What sexual side effects does finasteride cause?

The three main sexual side effects reported in clinical trials are erectile dysfunction (difficulty getting or keeping an erection), decreased libido (reduced interest in sex), and difficulty ejaculating. These are the same effects the FDA requires to be listed on the product label.

The Lee 2019 meta-analysis pooled 15 double-blind placebo-controlled trials and found finasteride 1mg was associated with a nearly 2-fold increase in erectile dysfunction vs placebo. Reduced sex drive and difficulty ejaculating also trended higher but did not reach statistical significance individually. The Mella 2010 meta-analysis of 12 trials reached the same overall conclusion.

How likely are sexual side effects with finasteride?

Based on pooled data from 15 controlled trials: 5 in every 100 men on finasteride reported a sexual side effect, compared to 3 in every 100 men on placebo. That means roughly 2 extra men per 100 experienced a side effect compared to what would be expected without the drug.

These numbers come from trials where side effects were self-reported, and researchers have noted that clinical trial adverse event reporting for finasteride has historically been inconsistent. Some analyses suggest real-world rates may differ from what trials captured.

The risk also appears concentrated in the first year of use. A large 4-year trial of finasteride 5mg found that new drug-related sexual side effects appeared mainly during year one, with rates between the treatment and placebo groups converging in years two through four.

Does finasteride cause erectile dysfunction?

Yes, based on clinical trial data. The Lee 2019 meta-analysis found men on finasteride 1mg were nearly twice as likely to report erectile dysfunction compared to men on placebo, and this finding was statistically significant. It is the strongest individual signal in the sexual side effects data.

The mechanism is tied to DHT (dihydrotestosterone, the hormone finasteride blocks). DHT plays a role in the blood vessels and nerve tissue involved in erections. Reducing systemic DHT can affect erectile function in some men. The majority of men in clinical trials did not report this side effect.

Does finasteride lower sex drive?

Reduced sex drive was more common in men taking finasteride than in men taking placebo, but the difference did not reach statistical significance on its own. When results were pooled across finasteride and dutasteride combined, decreased libido was statistically significant overall.

Decreased libido is listed as a known side effect on the finasteride product label. The fact that it did not reach significance individually in trials may partly reflect how side effects were measured: most older trials relied on spontaneous patient reports rather than structured questionnaires, which tend to undercount.

Are finasteride sexual side effects reversible?

For most men, yes. Clinical data suggests that sexual side effects resolve after stopping the drug in the majority of cases. A large long-term trial found that around half of men who discontinued due to a sexual side effect saw resolution after stopping.

However, a subset of men report side effects that persist long after stopping. The FDA noted in its 2022 label update that sexual side effects may continue after discontinuation. How often this happens and why remains an open question in the research.

What is post-finasteride syndrome?

Post-finasteride syndrome (PFS) is a term for persistent sexual, neurological, and psychological symptoms some men report after stopping finasteride, including ongoing erectile dysfunction, reduced libido, depression, brain fog, and fatigue lasting months or years after the drug is stopped. PFS was listed in the NIH database of rare diseases in 2019.

The medical community remains divided on PFS. Some studies point to biological changes in hormone pathways and brain chemistry. Others note that reported symptoms overlap with common conditions and that no confirmed causal mechanism has been established. No evidence-based treatment exists. Importantly, most men on finasteride do not develop PFS, and who is at risk cannot currently be predicted.

Evidence at a glance

Study	Year	Key finding
Lee et al. - sexual side effects meta-analysis	2019	66% higher risk of any sexual dysfunction vs placebo. Nearly 2x risk of erectile dysfunction. 15 trials, 4,495 men.
Mella et al. - oral finasteride efficacy and safety	2010	Finasteride 1mg increased sexual dysfunction risk vs placebo across 12 controlled trials.
Chen et al. - finasteride plus minoxidil	2020	Combination therapy showed no significant increase in adverse events vs monotherapy across 5 trials.

What the research cannot tell you

Whether you personally are at risk before starting. No genetic or physiological marker has been identified.
How often sexual side effects persist after stopping. Most trials did not follow men after discontinuation.
Whether side effect risk changes with longer-term use. Most trials ran for 6-12 months only.
The true prevalence of post-finasteride syndrome. No population-level data exists.
Why some men develop persistent effects and others taking the same drug do not.