A study by Chen found that deer antler velvet inhibits monoamine oxidase activity in the liver and brain tissues of aged mice. Monoamine-oxidase inhibitors prevent breakdown of monoamine neurotransmitters such as norepinephrine and serotonin. Antler apparently allows these vital neurotransmitters to be available longer to the brain structure, enhancing mood.
The IGF-1 in deer antler velvet can help increase the body's natural healing by affecting cell repair and growth. When an injury or surgery occurs that leaves a wound on the body, the wound is healed naturally by the cells which line the wound. Those cells multiply and rejoin over time. Using deer antler velvet can help promote faster cell repair and growth so that the wound can heal at a faster rate which means less time being injured or sore.
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.