Deer antler velvet is rich in insulin-like growth factor 1 (IGF-1) which is a growth hormone produced naturally in the liver as a response to human growth hormone (HGH) stimulation. This is a key factor in how deer antler velvet can help to promote muscle growth. IGF-1 works on the body by promoting the growth of healthy, lean skeletal muscles. This growth of healthy muscle mass can be influenced by IGF-1's tendency to increase muscle protein and muscle DNA content. There is evidence to suggest that IGF-1 acts on muscle tissue by promoting protein synthesis and the proliferation of satellite cells, both of which result in skeletal muscle growth due to the enlargement of the muscle cells.
According to an article in Sports Illustrated, Lewis spoke by telephone after his injury with Mitch Ross, co-owner of the supplement company S.W.A.T.S. (Sports with Alternatives to Steroids) to ask about treatments that could speed his recovery. Sports Illustrated reported that among Ross’ recommendations were deer antler pills to “rebuild your brain via your small intestines.” In addition to recommending the pills, Ross reportedly also told Lewis to spray deer antler extract under his tongue. Lewis has denied following this advice, and Ravens’ management has said that the star player has never flunked a drug test.
A systemic review on human interventions makes note of a study conducted on patients of osteoarthritis (Edelman et al. 2000; cannot be located online) which found improvements in joint pain symptoms relative to baseline in the Velvet Antler group and not placebo, although a lack of information on blinding and randomization precludes results that can be drawn from this study.