Finasteride may have adverse effects on semen

A study in the December 2013 issue of Fertility & Sterility has found that Propecia (finasteride), commonly used in reproductive-age men as a hair restorer, may cause reduced sperm counts in some men. The same medication in a higher dose is used as Proscar in older men for enlarged prostates.

The good news is that they found that sperm counts improve dramatically for most men after discontinuing the drug. There was an 11.6-fold increase in sperm counts after the drug was discontinued. The average dose was 1.04 mg. No man had a decrease in sperm count after discontinuation.

There was no change on hormone levels or other semen parameters such as sperm motility or sperm morphology.

They conclude that finasteride should be discontinued in subfertile men with low counts and used with caution in any men who desire fertility.