Using a DHT blocker is not a problem as long as libido and muscle are not issues. People who've used DHT blockers complain, however, that over a period of time they lose their libido and their muscle feels softer. Remember, although DHT does some bad things, it also gives muscle its hardness and gives a stronger libido. The thing about DHT is that too much is bad, and just the right amount is good.
That's why I avoided them because to me, muscle and libido are too important to sacrifice for hair.