Trestolone

Trestolone (7α-methyl-19-nortestosterone) is a synthetic androgen developed by the Population Council as a potential 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, under the brand name MENT, is an experimental contraceptive treatment and is not yet available commercially. It is currently being evaluated for safety and effectiveness in a number of scientific studies.

Mechanism of action
As a derivative of the anabolic steroid hormone nandrolone, trestolone's viability as a male contraceptive is twofold.

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 concetrations, 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 cutails 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.

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.