LGD-4033, also known as Ligandrol, is a compound that selectively targets androgen receptors. It is often used as a legal alternative to steroids by professional athletes and bodybuilders due to its purported anabolic effects and supposed lack of androgenic side effects (compared to steroids).
Having a high affinity towards AR (androgen receptors), LGD-4033 selectively binds to the androgen receptors in the muscles. It has a lower affinity for binding to other locations where androgen receptors are present in the body. Ligandrol carries an anabolic vs. androgenic ratio of 10:1.
Comparatively, natural testosterone carries a ratio of 1 to 1. Androgenic binding is one downside of using synthetic steroids to treat men in Testosterone Replacement Therapy due to major cosmetic and health side effects.
Research has been carried out on LGD-4033 over the years. The Pharmaceutical industry is interested in SARMs due to how they target and bind to androgen receptors.
Selectivity for targeting the receptors is a major consideration that medical research is interested in. High anabolic vs. androgenic ratios is something that is important when evaluating the theoretical safety of a specific SARM.