As a natural supplement, deer antler spray has no confirmed side effects, states WebMD, but insufficient information is available as of 2015 to determine whether it is safe. Deer antler spray is an aerosol liquid extract taken orally to build muscle and boost endurance.
The spray is made from a deer antler tissue called velvet, explains WebMD. Because deer antler spray contains a growth hormone called IGF-1, or insulin-like growth factor-1, it may act like estrogen. People with any pre-existing hormone-sensitive conditions should avoid deer velvet in any form. Current medical research indicates that taking deer velvet extract does not improve strength or aerobic capacity in active males undergoing strength training. WebMD states that the supplement does not improve athletic performance.
Deer velvet is the tissue that develops inside a deer's antlers before they fully harden, explains WebMD. A veterinarian clips the antler tips to harvest the tissue. Because this provides a naturally-occurring form of IGF-1, the Food and Drug Administration considers it a dietary supplement rather than a synthesized drug, and its sale is not regulated, notes Business Insider.
Both the FDA and the World Anti-Doping Agency ban IGF-1 as a proven performance enhancer, states Men's Health, but the hormone is ineffective if taken orally. It requires the injection of large, chemically purified doses to have any measurable effect on athletic performance.