Trestolone

Trestolone (INN), also known as (7α,17β)-normethandrone or as 17β-hydroxy-7α-methylestr-4-en-3-one, is a synthetic, steroidal androgen taken to build muscle rapidly, and is a theoretical candidate drug for use in hormonal male contraceptive methods. In males, regular administration of sufficient quantities of trestolone induces a state of temporary infertility.

Trestolone is an experimental contraceptive treatment and is not yet available commercially. It is currently being evaluated for safety and effectiveness in scientific studies, supported by the Population Council.

Mechanism of action

As a derivative of the anabolic steroid hormone nandrolone (19-nortestosterone), trestolone's viability as a male contraceptive is two-fold.

Inhibition of sperm production

Spermatozoa are produced in the testes of males in a process called spermatogenesis. In order to render a man infertile, a hormone-based male contraceptive method must stop spermatogenesis by interrupting the release of gonadotropins from the pituitary gland. Even in low concentrations, trestolone is a potent inhibitor of the release of the gonadotropin hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH).

In order for spermatogenesis to occur in the testes, both FSH and the male hormone testosterone must be present. By inhibiting release of FSH, trestolone creates an endocrine environment in which conditions for spermatogenesis are not ideal. Manufacture of sperm is further impaired by the suppression of LH, which in turn drastically curtails the production of testosterone. Sufficient regular doses of trestolone cause severe oligozoospermia or azoospermia, and therefore infertility, in most male patients.

Trestolone-induced sterility has been found to be quickly reversible upon discontinuation. Anecdotal evidence shows a 45-90 day reversal in most people with stimulation of LH and FSH. This includes clomiphene and human chorionic gonadotropin

Support of secondary sex characteristics

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 patients. Testosterone is the primary 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.

See also

• Methylestrenolone
• Norethandrolone