What many people don’t realize is that steroids actually take many forms, only some of which are useful in building muscles. In fact, many steroids are used to break down muscles, not build them. These steroids, called corticosteroids, are also used in other processes, like stress response, immune response, carbohydrate metabolism, and electrolyte levels. There are literally hundreds of varieties of naturally occurring steroids, and they’re made by everything from fungi to virtually every vertebrate life form on the planet. The human body not only produces Testosterone naturally, but also produces other steroids like Cholesterol and Cortisol, for example.