Numerous sources have claimed that Deer Antler Spray , purportedly extracted from cervid sources, contains IGF-1.     Credence to this claim comes from the fact that deer's antlers grow extremely rapidly and that the associated cellular factors can similarly aid in skeletal healing in humans. IGF-1 is currently banned by various sporting bodies. However, sprays and pills claiming to be 'deer antler velvet extracts' are freely available on the market.  As IGF-1 is a protein, it cannot be absorbed orally since it is rapidly broken down in the gastrointestinal tract .  In September 2013, the headquarters of SWATS, a well-known distributor of deer antler spray and other controversial products, was raided and ordered to shut down by Alabama 's attorney general citing "numerous serious and willful violations of Alabama’s deceptive trade practices act".   Deer antler spray has been linked to prion disease. 
Of greater concern is the fact that milk from rBGH-treated cows has higher levels of IGF-1, a hormone that normally helps some types of cells to grow. Several studies have found that IGF-1 levels at the high end of the normal range may influence the development of certain tumors. Some early studies found a relationship between blood levels of IGF-1 and the development of prostate , breast , colorectal , and other cancers, but later studies have failed to confirm these reports or have found weaker relationships. While there may be a link between IGF-1 blood levels and cancer, the exact nature of this link remains unclear.