I presume you mean steroids and other substances used by bodybuilders, sport athletes and individuals to build bigger, stronger muscles. If my presumption is correct, then yes, not only do males use it, but females too, though more common with males. To further answer your question, it is used as a short-cut means to build muscle giving you fast result when compared with the natural way which you don't take or use any substance but strictly diet exercises and weight lifting. People use substances or bulk enhancers for various reasons. For some, it's because of the kind of sport they do where muscles is an advantage, while others may use it for other reasons. Some of them may be legal and approved while others are illegal ( banned). An example is anabolic steroids. However, it is worth mentioning that, be you a bodybuilders, a sports man or woman or just a fitness enthusiast, the healthy, safest and best way to bulk up is the natural way. The process may be slow though, but gives you best results with no side effects or health conditions. My sincere advice.