When LH release is inhibited, the amount of testosterone made in the testes declines dramatically. As a result of trestolone's gonadotropin-suppressing qualities, levels of serum testosterone fall sharply in men treated with sufficient amounts of the medication. Testosterone is the main hormone responsible for maintenance of male secondary sex characteristics. Normally, inadequate testosterone levels cause undesirable effects, such as fatigue, loss of skeletal muscle mass, reduced libido, and weight gain. However, the androgenic and anabolic properties of trestolone largely ameliorate this problem. Essentially, trestolone replaces testosterone's role as the primary male hormone in the body.