Chemical Reagent

CAS 566-48-3 Formestane

Product Name: Formestane
Alias: Lentaron
CAS register number: 566-48-3
Molecular formula: C19H26O3
Molecular Weight:302.4126
Melting point: 199-202°C
Assay: 99%
Appearance: white or light green crystalloid
Grade:Pharmaceutical Grade

Formestane (lentaron, chemical name: 4-hydroxyandrostenedione) is a type I steroidal aromatase inhibitor (AI). It was developed for use in treatment of estrogen-receptor-positive breast cancer in post-menopausal women. For medical purposes, it is made in intramuscular depot form and injected. It is not used in oral form due to poor bioavailability, which makes the oral version inferior to aromasin, letrozole, and arimidex.

Decreasing SHBG

According to studies, formestane can lower SHBG up to 34%, which will increase free testosterone levels. SHBG (sex hormone binding globulin) is a protein that binds to sex steroids, and renders them inactive, for as long as SHBG is bound to them. There is a difference between ‘free’ testosterone, and ‘bound’ testosterone. Free testosterone is what matters, so lowering SHBG will increase ‘free’ testosterone. Higher testosterone means more strength, muscle mass, less body fat, better sense of well being, and libido.