Finasteride can lower sperm count and semen volume in some men, but for most the effect in studies was small and went back toward normal after stopping. The Propecia label lists male infertility and poor semen quality among reports after approval, and notes that semen quality improved after stopping in reported cases. Men who are trying for a child, or who already have fertility problems, are the group the research says to think about most.
If that is you, this is a conversation for your prescriber and, ideally, a fertility specialist before you change anything. The page below lays out what the studies measured.
TL;DR
- In a one-year trial of healthy men, total sperm count fell by about a third at six months, then the drop was smaller and no longer significant by one year.
- On the hair loss dose, the label reports an 11 percent median drop in ejaculate volume, against 8 percent on placebo.
- In a fertility clinic, men with low counts on finasteride saw counts rise, on average more than tenfold, after stopping.
- The label lists infertility and poor semen quality among reports after approval, with improvement reported after stopping.
- Trying to conceive? Ask about a semen analysis and whether to pause, rather than deciding alone.
Important
This article is educational and not medical advice. If you are worried about sudden shedding, scalp symptoms, or side effects, talk to a licensed clinician.
What the label says
In a study of healthy men on the hair loss dose, the Propecia label reports a median drop in ejaculate volume of 11 percent after 48 weeks, against 8 percent on placebo. At five times that dose, used for the prostate, two studies found a larger drop of about 25 percent that reversed after stopping. Among reports collected after approval, the label lists “male infertility and/or poor seminal quality” and adds that normal or improved semen quality has been reported after stopping (Propecia label on DailyMed).
The controlled trial in healthy men
A randomised, placebo-controlled trial gave 99 healthy men finasteride at the prostate dose, dutasteride or a placebo for a year. On finasteride, total sperm count was 34.3 percent lower than at the start after 26 weeks, 16.2 percent lower at 52 weeks, which was no longer a significant difference, and 6.2 percent lower 24 weeks after stopping. Sperm motility fell by 6 to 12 percent, and shape did not change. The authors described the effects as mild and apparently reversible (Amory and colleagues, 2007). That trial used a higher dose than the one prescribed for hair loss.
Men already seeing a fertility clinic
The picture looks different in men who already have fertility problems. A Canadian fertility clinic found 27 of 4,400 men seen for infertility were taking finasteride, on average at the hair loss dose. After they stopped, sperm counts rose on average 11.6-fold, and 57 percent of those with severe oligospermia, a very low count, rose above 15 million per millilitre. No man's count fell. Hormone levels, motility and shape did not change. The authors suggested stopping finasteride in subfertile men with low counts and using it with caution in men who want children (Samplaski and colleagues, 2013).
This was a small group without a comparison arm, and it was selected because the men already had fertility problems. It suggests that a drug effect most men would never notice may matter for a few.
Pregnancy and handling tablets
The label separately warns that women who are pregnant or may become pregnant should not handle crushed or broken tablets, because finasteride can affect the development of a male fetus (Propecia label). Questions about a partner's pregnancy belong with your prescriber.
What to record and ask
- Your plans: tell your prescriber if you are trying to conceive now or within the next year.
- Dates: when you started finasteride and any change in it.
- Other factors: other medicines, smoking, alcohol and recent illness, which your doctor may ask about.
- Test results: keep every semen analysis with its date, so a later one can be compared.
- Hair photos: keep your usual set, so any pause in treatment can be judged on both sides. See tracking shedding after stopping finasteride.
When to get advice
Ask your prescriber before trying to conceive, and see a fertility specialist if you have been trying without success. Bring your finasteride dates. Do not stop or restart on your own; a planned change with your doctor lets you record what happens to both your hair and your test results.
Next step
If a child is in your plans, raise it at your next appointment and ask whether a baseline semen analysis makes sense. Write the answer and the date in your log.
Related reading
- Post-finasteride syndrome: what to track
- Finasteride drug interactions checklist
- DHT and hair loss explained
Sources: Propecia prescribing information, DailyMed; Amory et al. 2007, Journal of Clinical Endocrinology and Metabolism; Samplaski et al. 2013, Fertility and Sterility.
