While there are multiple causes of testicular atrophy, the most common cause in resource-rich settings is the use of anabolic steroids and their congeners in the treatment of male hypogonadism or testicular hypofunction.
It is perhaps the most dreaded side effect of Testosterone replacement therapy. While completely benign and reversible in most cases, it becomes an issue of cosmesis as well as reduced ejaculatory volume. The latter is due to the testes significantly contributing to the ejaculatory fluid volume.
Testicular atrophy may be treated with Human Chorionic Gonadotropin (HCG), a peptide hormone usually obtained from the urine processing of pregnant women. You may have heard of it as Pregnyl® or Novarel®. It is a safe and well-tolerated injectable agent that can be safely and efficiently injected under the skin.