Andarine, also known as S-40503 or S-4 for short, is a selective androgen receptor modulator, or SARM. Pharmaceutical companies developed andarine for the treatment of osteoporosis and muscle wasting disease. The compound helps build stronger bones and muscle mass but is especially effective at decreasing body fat, providing bodybuilders with “a cut look.”

SARMS is a broad term referring to various substances that bind to androgen receptors and activate in certain tissues such as muscle and bone. Though some early SARMS were steroidal in origin, the term SARMS commonly refers to a new and distinct category of drugs—Non-steroidal Selective Androgen Receptor Modulators—which is part of their appeal. Tissue selectivity is a key component of how SARMS are seen to work, bolstering gains in certain areas with less damage to other body parts such as the liver or prostate. SARMS continue to be evaluated for their potential to serve as effective medicines in combating muscle-wasting conditions and other disorders. However, the safety and efficacy of SARMS in general has yet to be established, and no SARM has been approved as a drug for human use.

A Banned Substance in Sport:
Andarine, along with other SARMS, was added to WADA’s Prohibited List in 2008 and remains banned today. Since 2010, a number of athletes, including some in track and field, have tested positive for the prohibited substance. As a category, SARMS has become one of the more prevalent anabolic agents reported in sport drug testing.

Illegal Dietary Supplement Ingredient:
Unfortunately, unscrupulous companies tout andarine, ostarine and other SARMS as being “completely legal” and have helped to popularize them as active ingredients in dietary supplements. Such claims are simply not true, as no SARM is considered a legal dietary supplement ingredient nor has any been approved for human consumption.

In the United States, andarine and other SARMS can only be used for research and medical-testing purposes. Often the unscrupulous brands attempt to hide behind the suggestion that their products are only for research use, but that excuse is voided as soon as a product is capsulated or put into a liquid form and dosed for human consumption. Do not be fooled by this ruse; SARMS are illegal dietary supplement ingredients and their inclusion in a product is considered sale of an unapproved drug by the FDA (U.S. Food & Drug Administration) and most of its global equivalents.

Supplement consumers should beware that andarine other SARMS have invaded the dietary supplement industry, creating the real possibility of cross-contamination occurring in the manufacturing environment or in raw material sourcing. Because of the significant money available to manufacturing facilities that are willing to break the law and make SARMS into dietary supplement products, some end up manufacturing SARMS in otherwise legitimate facilities clandestinely, often after hours, exposing other legitimate products to contamination. A circumstance like this resulted in an athlete testing positive who had used a benign supplement that was made in a facility that also produced SARMS. This problem magnifies the importance of certification programs like BSCG’s those test supplement products to demonstrate they are free of andarine, other SARMS and a range of doping agents.

Reports of impaired vision and eye discomfort are common with andarine use. Users often experience blurred and yellowish vision, especially at night, and vision flashes have also been reported. These effects occur as the S4 molecule binds to the receptors in the eye; the more aggressive the binding, the more discomfort that is experienced. Visual disturbances were found to be so common during clinical trials for the drug that the trials were abandoned.

Andarine tends to suppress natural testosterone production more than other SARMs. This drug is also understood to cause depression in some users. Questions have arisen over the potential effects of SARMs on cancer growth.

USADA: