Q: I have been on Propecia for approximately 5 years. What does Propecia do to your PSA level, lower it or make it higher? Also, what would you consider a normal level while on Propecia?

A: Finasteride 1mg a day lowers your PSA around 50%. Therefore, when patients are taking finasteride, the PSA reading should be doubled.

Finasteride does not appear to decrease the sensitivity of the PSA test to detect prostate cancer – its main purpose.

PSA levels vary by age and by lab so I would check with your internist/urologist to evaluate your specific level.

In very general terms, for adults, it is ideal to have a PSA < 1.0 off Propecia and < 0.5 on it, but higher levels can also be fine.