Pro-steroids, known as prohormones, were the legal form of steroids before they were banned in 2005. However, before then these pro hormones showed up in 1996. Many people considered these pro-hormones to be much like creatine or performance enhancers. Then, these pro-steroids really gained national attention when Mark McGuire announced that he had used andro, short for androstendione, to enhance his performance.

Once it was known that this amazing baseball player was taking these supplements people in sports and the bodybuilding industry were debating about whether these supplements were effective and if so should they be allowed. The first versions were quite expensive and nobody is sure if they actually worked despite costing an arm and a leg. However, the more recent versions certainly work and they help people add lean muscle mass all the while reducing gaining fat. When used safely and by educated people these pro-hormones are really effective.

Basically, prohormones are hormones but when they are swallowed and digested an enzymatic process turns them into anabolic hormones. This is basically taking a hormone and letting the body convert it to an anabolic steroid rather than taking the anabolic steroid outright. There really is no difference. The fact that natural enzymes are required to change these pro-hormones into anabolic steroids is what kept them from being illegal. However, eventually not even that could save them.

The way these hormones work is they increase the body's level of anabolic hormones and in turn this stimulates androgen receptors that help people get bigger and build muscle. The cause a reaction in the body so that more nutrients are used to build muscle and reduce the availability to store fat. The way these pro-hormones work depend on the amount of enzymes the body naturally has available. The enzymes that are required for this reaction occur on a limited basis within the body so only a certain amount can be taken to receive the desired reaction. If more are taken it will not improve the pro hormones simply because there are no additional enzymes within the body to cause the necessary reaction. This makes them less dangerous than traditional anabolic steroids and the risk of negative side effects are lowered significantly. The capability to build muscle is limited as well because of this.

So, pro-hormones are not anabolic steroids but they turn into them once digested and the enzymatic reaction takes place. As a result, the way these pro-hormones affect the body is very similar to the way anabolic steroids affect the body but to a lesser extent. Then, these pro-steroids really gained national attention when Mark McGuire announced that he had used andro, short for androstendione, to enhance his performance.