When it comes to steroids, undoubtedly the side effects that scare people the most are those related to estrogen and its side effects. This is very common when you consider the fact that as a man, the primary reason you have masculine features is due to higher levels of testosterone in comparison to estrogen. For women, the inverse is true. This is very important to understand because whenever you dose with an exogenous compound, you’re going to throw your hormone levels out of whack. This means that whenever you do engage in using one of these compounds, you have to understand that whenever you introduce higher levels of androgenic (testosterone producing compounds) compounds, these are going to result in feedback levels of estrogen in response. This is very important to keep in mind because otherwise, you will be unable to stave off the bad effects that you would otherwise experience from the compound.
Testosterone Propionate also converts to both Estrogen (through Aromatization) and Dihydrotestosterone (through 5a-reduction). Most of the side effects people experience with testosterone use is actually from it’s conversion to these two substrates. Thus, hair loss , water retention, acne, and other side effects are possible with use of this drug. Conversion to these hormones is also responsible for some of testosterone’s ability to build muscle; therefore when many side effects are avoided with the use of ancillary compounds, some of the muscle building properties are also stunted.