Many bodybuilders are starting to go beyond steroids and use growth hormone and now IGF-1. Recent research suggests that IGF-1 may play a big role in cancer formation. Harvard Medical School scientist showed that exposure to high amounts of IGF-1, may increase risk of many forms of cancers. The researchers noted that the studies are not conclusive though. Cancer is a very complicated disease and diet, environment, and genetics is a big factor in the cause of cancers. It’s best to not put these highly anabolic hormones in your body at all, so you have less risk of cancer.