Andarine (S4, GTX-007)
Description
Andarine is a second generation Selective Androgen Receptor Modulator (SARM). SARMs are all closely related to anabolic steroids in activity. They bind the same cellular androgen receptor (AR), and impart similar anabolic effects. However, like andarine, most are non-steroidal in structure. They are also highly selective in their receptor interactions (hence the name). These drugs are often full agonists of the AR in “anabolic” tissues such as bone and skeletal muscle, but only partial agonists in “androgenic” areas like the prostate and sex organs. As such, they should have a significantly higher separation of anabolic and androgenic effect. There is also no conversion to estrogen, and likely minimal spillover with other hormones.
SARMs are intended to replicate some benefits of anabolic steroid therapy, but with fewer side effects such as prostate hypertrophy, male pattern hair loss, and virilization. Many options for, among other things, primary and secondary currently under investigation as therapeutic hypogonadism, osteoporosis, age-related muscle wasting (sarcopenia), acquired immunodeficiency syndrome (AIDS) and cancer-related wasting (cachexia), anemia, and benign prostatic hypertrophy. Some may also turn out to be efficacious as oral male contraceptive agents. Research in this area is still early, however. Though not a developed medicine, andarine is already widely in use in the sports community as a muscle-building alternative to anabolic steroids. In animal studies, andarine has demonstrated roughly comparable anabolic effect (on muscle) as testosterone propionate. However, this came with only 30-40% of its relative androgenicity. It has also been shown to increase strength and body weight similar to dihydrotestosterone (DHT), yet is stronger at preventing and restoring bone loss. Andarine significantly decreased total fat mass of treated animals as well, which is likely attributed to its pure anabolic (non estrogenic) action. What is most critical though, at an anabolic-effective dosage, andarine provided minimal stimulation of the prostate, and only modest inhibition of the HPTA. Studies like these seem to underline andarine’s early potential as a therapeutic agent. Andarine has not been subject to full human clinical trials. Substantive data on the efficacy and potential toxicity of world effects and side effects in humans has, likewise, been this drug is actually quite limited. Information on its real largely based on observation and anecdote. So far, reports suggest that andarine does produce noticeable gains in lean muscle mass and strength. This is often accompanied by noticeable fat loss. However, it should be noted that it also appears prone to adverse reactions, particularly visual disturbances (See: Side Effects). And it is perhaps not as potent or refined as some newer SARMs. As of late, this drug seems to be losing some favor to other agents of this class.
Key Points
- Mild/Moderate Anabolic Effect
- Moderate HPTA Suppression
- Mild Hepatotoxicity
- Mild/Moderate Lipid Changes
- Visual Disturbances
History
Andarine was first described in 2001, in a U.S. patent filing by The University of Tennessee Research Corporation. The drug was subsequently under development by the American company GTx Inc. The earliest research on this substance was published in 2004. It used a rat model to investigate the effects of andarine on the prostate, and its potential with benign prostatic hypertrophy.6 GTX partnered with Ortho Biotech to develop andarine as a medicine for the treatment of cancer cachexia (wasting). The drug entered Phase 1 human trials, with Phase Il trials planned. However, research was discontinued. This substance may have taken a back seat for more recent innovations in this space, which is now becoming quite crowded with research substances. GTx itself seems more focused on ostarine, which has been extensively studied in humans. These days, most papers on andarine look at its use in sports doping. This drug has been on the WADA banned substance list since 2008, and detectable in doping controls since 2010.