As an AAS, trestolone is an agonist of the androgen receptor (AR), similarly to androgens like testosterone and dihydrotestosterone (DHT). Trestolone is not a substrate for 5α-reductase and hence is not potentiated or inactivated in so-called "androgenic" tissues like the skin, hair follicles, and prostate gland. As such, it has a high ratio of anabolic to androgenic activity, similarly to other nandrolone derivatives. Trestolone is a substrate for aromatase and hence produces the estrogen 7α-methylestradiol as a metabolite. However, trestolone has only weak estrogenic activity and an amount that would appear to be insufficient for replacement purposes, as evidenced by decreased bone mineral density in men treated with it for hypogonadism. Trestolone also has potent progestogenic activity. Both the androgenic and progestogenic activity of trestolone are thought to be involved in its antigonadotropic activity.