Results of a study of Vasalgel in rhesus macaques have been published. Vasalgel is being developed by a social venture as a non-hormonal, long-acting, potentially reversible male contraceptive. It is a polymer hydrogel that works by blocking sperm in the vas deferens. Injection of Vasalgel in sexually mature adult male rhesus monkeys was effective in preventing conception throughout the one-plus year study period.