One major reason why steroid users usually cycle is so they can regain their natural testosterone levels. During steroid use, your testicles shut down their natural teststerone production. Your testicles shrink because they are no longer “active”. As the anabolic steroids leave your body, your body slowly revs back up it’s production again and your testicles grow back in size.

After short cycles or infrequent use, most will bounce back fairly easily, especially with the use of anti-estrogens post-cycle. Anti-estrogens help boost testosterone levels post cycle by lowering estrogen, an important indicator for the body in regulating testosterone production in the testicles. However, there are some people who struggle to get testosterone back after even their very first cycle. It seems to be genetically determined because some can recover no problems without even anti-estrogens, while others have shrunken testicles and low testosterone problems for many weeks or even months. It’s pretty easy to tell you have low testosterone, you’ll feel like a 10 year old girl scout and you won’t even be able to maintain your gains.

Patrick Arnold, a expert in steroid chemistry and use, has said in the past that some people are pre-disposed to having trouble recovering their testosterone levels post-cycle. He recommends an extra long course of anti-estrogens or even possibly HCG as a final resort. Anti-estrogens usually are only taken for 2 to 4 weeks, but those with problems recovering should probably due it much longer. HCG (Human chorionic gonadotropin) is injected to jumpstart testicles sometimes because it acts like LH, a hormone that directly stimulates the testicles. The one downside to HCG is that overuse will actually cause too much testosterone causes a negetive feedback responce, once again inhibiting natural testosterone production.

Your testicles usually fully recover pretty quickly after one cycle or infrequent use, but long term abuse is another thing. You could possibly damage your testicles by staying on too long or doing too many steroid cycles over the years. It is hard to say how much damage, it would vary by the individual and their history of use. Problems would build up cumulatively, so that is why it is best to do your steroid cycles infrequently, so you allow the body to fully recover in between each one. There are reports of some former pro-bodybuilders or heavy steroid users having to take HRT (Testosterone replacement) because they have damaged their natural testosterone production. Many pro-bodybuilders never go off steroids because they won’t even be able to maintain their muscle if they did so. This will surely cause irrevecoble damage to their fertility and ability to produce testosterone.