A new study has some unfortunate news for men who have been treating their hair loss with drugs like Propecia and similar medications: it could be resulting in long-term sexual problems. While the overall risk is fairly low at 1.4 percent of men who took the drugs, it’s a statistically significant number, and they had problems more than three years after they stopped taking the drugs.

And another 4.5 percent of men who took the hair loss drugs had shorter term erectile dysfunction, according to the study, which was conducted by researchers at Northwestern University. The study found that the younger the man was who took the drugs, the larger the risk was to their sexual health.

In addition to Propecia, brands like Proscar and Avodart may carry risk. The drugs are meant to treat the effects of age on men when their prostate enlarges, which results in a range of issues. A lower dose of these drugs is often prescribed for hair loss.

“Our study shows men who take finasteride or dutasteride can get persistent erectile dysfunction, in which they will not be able to have normal erections for months or years after stopping finasteride or dutasteride,” said lead study author Dr. Steven Belknap, a research assistant professor of dermatology at Northwestern University Feinberg School of Medicine.