In a study on the apoptotic effect of gossypol on human lymphocytes, gossypol was used at 20-50 mM to induce apoptosis in human lymphocytes without causing necrosis through cytotoxic effects. The combined use of steroid hormones (methyltestosterone and ethinyl estradiol) and gossypol (low dose) in an antifertility study in rats showed that the steroid hormone made the procedure of spermatogenesis slower and low dose gossypol caused all sperm to lose their activity in the epididymis.