Some bodybuilders and athletes use trenbolone esters for their muscle-building and otherwise performance-enhancing effects.  Such use is illegal in the United States and many other countries. The DEA classifies trenbolone and its esters as Schedule III controlled substances under the Controlled Substances Act .  Trenbolone is classified as a Schedule 4 drug in Canada  and a class C drug with no penalty for personal use or possession in the United Kingdom .  Use or possession of steroids without a prescription is a crime in Australia .  The infamous "duchess" cocktail administered to Russian athletes at the Sochi Winter Olympics consisted of oxandrolone , a metenolone ester, and a trenbolone ester. 
Tren is an extremely androgenic hormone, and as a result well known for promoting androgenic side effects. Hair loss and acne in men who are predisposed are both possible. Body hair growth is also possible. If you are not genetically predisposed no amount of Tren on earth with cause these issues. The androgenic side effects of Tren are truly based on genetic response. When it comes to hair loss, if you are predisposed to male pattern baldness, meaning at some point you’re going to lose your hair regardless of steroid use , Tren is one of the fastest ways to ensure you lose your hair a little sooner.
Virilization is a serious androgenic side effect of Tren. It is very difficult for a woman to use Tren without some level of virilization and makes it a steroid that’s almost never recommended for female use.
Important Note: The 5-alpha reductase enzyme does not metabolize the Trenbolone hormone. This means 5-alpha reductase inhibitors like Finasteride will not affect the androgenicity of the hormone.
It is very common for bodybuilders to use veterinary steroids for a precontest cycle. Since they are typically assimilated quickly, they do the best work in the shortest amount of time, and are generally out of the system relatively fast in comparison to other ‘roids. And, believe it or not, usually people see fewer side effects when using vet products than when using human ones. Why take anything else? Maybe not ‘why take anything else’, but why not include veterinary steroids, in one form or another, in every cycle? In my mind, veterinary drugs should really be everyone’s choice for extreme condition and definition. They combine well with androgens and other anabolics as well as any drug in the human realm of anabolic steroids. The only problem, these days anyway, is availability. You can find them in Mexico, but you risk fakes, counterfeits, lower quality, or lower dose per ml. You also, of course, face the possibility that you’ll be stopped.