Masteron is that it is actually a weak (though useful) anti-estrogen, and that’s where a lot of its “hardening” properties probably come from, and why it’s so useful in precontest cycles. Masteron may actually interact with the aromatase enzyme to inhibit aromatization (conversion/metabolism) of other steroids into estrogen. Additionally, Masteron seems to be able to interact with estrogen at the receptor site. I think this explains it’s “hardening” properties, because with less estrogen in your body, you’ll be holding less water and therefore appear harder. This is also why people say it “only works” at a low bodyfat percentage. When you take the water retention off of a fat person, you still have a (dryer) fat person. And if you aren’t using a lot of different aromatizable drugs (and are using them in low doses), or drugs that potentiate estrogen’s effects (and I’m thinking about the 19-nor family here) then Masteron is likely to be the only anti-estrogen you need. Masteron Enanthate is especially effective for this purpose because it has a very long active life and relatively constant blood plasma levels.
Because the ultimate goal of a steroid cycle is to increase strength and muscle size, the associated spike in estrogen which accompanies steroids such as Testosterone is considered undesirable. In order to disassociate the two effects, two classes of drug are used. Medications such as Nolvadex or Clomid target the estrogen receptors. They make it more difficult for the estrogen to exert it’s influence within the body thus allowing the testosterone to act more freely. The second class is aromatase inhibitors such as Femara. They target the aromatase enzyme itself in order to prevent the production of estrogen in the first place. Sometimes, it’s not always clear which option you should go with or even what the differences are between the two. Lets clear that up a little.