Selective Androgen Receptor Modulators (SARMs) are a class of therapeutic compounds that have similar anabolic properties to anabolic steroids, but with reduced androgenic (producing male characteristics) properties. As an example, the androgen receptor is activated by binding androgens, such as testosterone. Unlike anabolic steroids, which bind to androgen receptors in many tissues all over the body, individual SARMs selectively bind androgen receptors in certain tissues, but not in others.
Currently used androgens for male hormone replacement therapy are typically injectable or skin delivery formulations of testosterone or testosterone esters. Injectable forms of testosterone esters (such as testosterone enanthate, propionate, or cypionate) produce undesirable fluctuations in testosterone blood levels, with overly high levels shortly after injection and overly low afterward. Skin patches do provide a better blood level profile of testosterone, but skin irritation and daily application still limit their usefulness.
SARMs provide the ability to design molecules that can be delivered orally, but that selectively target the androgen receptors in different tissues differently. The goal of research in this area is to allow a customized response: Tissues that are the target of the therapy will respond as they would to testosterone; other tissues where undesirable side-effects are produced will not.
In 2013, some supplement companies began selling various SARMs as supplements, in purported violation of both the Food and Drug Administration’s Dietary Supplement Health and Education Act of 1994 (DSHEA) and the intellectual rights of the patent holders of the compounds. In 2017 it was found that many of the supplements being sold claiming to be SARMs do not actually contain the chemical in question.