Mestanolone, also known as methylandrostanolone and sold under the brand names Androstalone and Ermalone among others, is an androgen and anabolic steroid (AAS) medication which is mostly no longer used. It is still available for use in Japan however.It is taken by mouth.

Available forms

Mestanolone was available in the form of 25 mg sublingual tablets (brand name Ermalone).

Pharmacodynamics

Mestanolone is an AAS, with both androgenic and anabolic effects. It is very similar in its effects to androstanolone (dihydrotestosterone; DHT), and can be thought of as an orally active version of this AAS.Due to inactivation by 3α-hydroxysteroid dehydrogenase (3α-HSD) in skeletal muscle, mestanolone is described as a very poor anabolic agent, similarly to androstanolone and mesterolone.As mestanolone is 5α-reduced, it cannot be aromatized and hence has no propensity for estrogenic side effects such as gynecomastia.The drug also has no progestogenic activity.Like other 17α-alkylated AAS, mestanolone is hepatotoxic.

Pharmacokinetics

Due to its C17α methyl group, unlike androstanolone, mestanolone is orally active.

Side effects

Side effects of mestanolone include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.It can also cause liver damage.The drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).

It has strong androgenic effects and weak anabolic effects, which make it useful for producing masculine psychological and behavioral effects.The drug has no estrogenic effects.