Finasteride and Fertility: Semen Parameters, Sperm Quality, Evidence Review

DHT plays a role in spermatogenesis and the male reproductive tract, which raises the question of whether finasteride’s 5α-reductase inhibition affects male fertility. The published evidence consistently shows modest semen parameter changes in most men that reverse upon drug cessation, though individual case reports of more severe impacts exist.

Key Research

Study	Population	Findings
Overstreet JW, et al. 1999 (J Urology)	181 men aged 19-41; randomized, placebo-controlled; fin 1 mg for 48 weeks	No significant effect on sperm concentration, total sperm count, motility or morphology; ejaculate volume fell 11% vs. 8% with placebo (not significant)
Kiguradze T, et al. 2017 (PeerJ)	Nested case-control; US insurance database, 11,909 men	Finasteride use associated with persistent sexual dysfunction in younger men in a pharmacoepidemiological signal analysis

WHO Normal Reference Ranges in Context

The current WHO 2021 lower reference limits for semen parameters provide context for evaluating study findings:

Parameter	WHO 2021 Lower Reference
Sperm concentration	≥16 million/mL
Total sperm count	≥39 million/ejaculate
Progressive motility	≥30%
Normal morphology	≥4%

Clinical Guidance Summary

• Most men taking finasteride 1 mg do not experience clinically significant semen parameter changes
• Men planning conception should discuss temporary discontinuation with their prescribing physician; recovery of semen parameters after stopping is typically expected within 3-6 months
• Men experiencing infertility while on finasteride should have semen analysis performed and consider specialist consultation

What the Evidence Shows

Parameter	Typical finding on finasteride	Reversibility
Semen volume	Modest reduction in some men	Reverses after stopping
Sperm count	Generally within normal range; rare azoospermia reported	Reverses in most cases
Sperm motility	Some studies show modest reduction	Reverses after stopping
Sperm morphology	Mixed findings; no consistent adverse signal	N/A

Guidance for Men Planning Conception

• If fertility is a current or near-term priority, discuss with your urologist before starting finasteride
• Men already on finasteride who plan to conceive should discuss whether and when to stop with their provider, typically 3-6 months before trying is suggested, though evidence on optimal cessation timing is limited
• Men with baseline subfertility (low sperm count, poor motility) should be particularly cautious
• For men with normal baseline fertility, the risk of clinically significant impairment is low but not zero

Sources

• Overstreet JW, et al. “Chronic treatment with finasteride daily does not affect spermatogenesis or semen production in young men.” J Urol. 1999;162(4):1295-1300.
• World Health Organization. WHO laboratory manual for the examination and processing of human semen. 6th ed. 2021.