According to modern research, deer antler velvet has shown gonadotropic activity. Studies by both Fisher and Wang indicate that deer antler velvet may increase testosterone levels in men and can help prevent some conditions associated with aging. The estrogen hormone most affected by deer antler velvet is estradiol. Estradiol is a precursor to testosterone.
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.