I have seen quite a few post lately asking about DHTs such as winny/masteron/proviron/anavar and any possible anti-estrogen effects it may or may not have. For the record DHTs (Dihydrotestosterones and their metabolites) do act as anti-estrogens. Here's how and why: DHT acts as a competitive antagonist to the estrogen receptor. DHT will decrease estrogen-induced RNA transcription at a point subsequent to estrogen receptor binding. Also, DHTs have been shown to directly block the production of estrogens from androgens by inhibiting the activity of the aromatase enzyme, i.e. the DHT(or DHT metabolite) will bind to the aromatase enzyme and inhibit the formation of estrone from androstenedione.

Some people worried about prostrate size/growth take Proscar. DHTs cause prostrate growth. Proscar is a 5α-reductase inhibitor which prevents the conversion of testosterone to dihydrotestosterone (DHT) in the body. So less DHT equals less prostrate growth. Do you know what the side effect of Proscar is? You quessed it, gynocomastia, female breast growth in men. You know why? reducing DHT in the male body reduces your protection against estrogen in the body. Less DHT leads to increased estrogen.

I hope this clears things up for people and please feel free to comment or even disagree just remember if you do disagree that you are wrong.