The problem is that dihydrotestosterone (DHT) does much more than contribute to hair loss. It also plays a crucial role in male sexual development and mood regulation. When DHT levels are reduced, either intentionally or unintentionally, it can impact these functions in unwanted ways and cause:
Impotence,
Lower sex drive,
Difficulty achieving orgasm,
Abnormal ejaculation,
Gynecomastia (male breast development),
Depression.
However, these side effects only appear in a small minority of men. As with any medication, you should discuss with your hair loss physician whether DHT blockers or other pharmaceutical treatments offer a viable and effective option for addressing your hair loss issues.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481923/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4064044/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5023004/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4339524/