Andarine

Andarine, designated S-4, is a non-steroidal selective androgen receptor modulator (SARM) with the chemical structure S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethyl-phenyl)-propionamide. It belongs to the arylpropionamide family of SARMs derived from early antiandrogen chemistry related to bicalutamide, and was developed in the laboratory of James Dalton and colleagues at the University of Tennessee and Ohio State University during the early 2000s ^[3]. Unlike anabolic steroids, SARMs are designed to bind the androgen receptor and act as tissue-selective agonists, producing anabolic effects in muscle and bone while sparing, or only partially stimulating, tissues such as the prostate ^[1].

In preclinical studies, andarine restored muscle mass and strength and prevented castration-induced bone loss in male rats, and it maintained bone mineral density while reducing body fat in a female ovariectomy model of osteoporosis, supporting interest in it for conditions like muscle wasting, benign prostatic hyperplasia, and osteoporosis ^[1][2]. Pharmacokinetic work in rats characterized it as orally bioavailable with a half-life of a few hours ^[3]. Despite this promising profile, andarine itself did not advance to approved clinical use, and no SARM has yet received full regulatory approval as a medicine.

Andarine is prohibited in sport; it was added to the World Anti-Doping Agency Prohibited List, and forensic laboratories have repeatedly detected it as an adulterant in black-market products and in human and equine doping-control samples ^[4][5][6]. It is sold on the research-chemical and supplement gray market, often as an oily liquid or in capsules, but it is not an approved therapeutic and its long-term human safety has not been established ^[4].

Andarine (S-4) is a selective androgen receptor modulator sold as a research chemical and not approved for human use; like other SARMs it can suppress natural testosterone and the HPTA, shift cholesterol unfavorably, and strain the liver. A characteristic reported effect is a yellow-green tint or difficulty with night vision. Long-term cardiovascular safety is unknown, virilizing effects can occur (particularly in women), and it is prohibited in sport.

Andarine, also known as S-4 or GTx-007, was developed in the early 2000s by the biopharmaceutical company GTx in collaboration with researchers at the University of Tennessee, notably James Dalton and Duane Miller. It was built from arylpropionamide chemistry, the same class that gave rise to the anti-androgen bicalutamide, and it was among the first non-steroidal selective androgen receptor modulators, or SARMs, to be characterized in detail. In preclinical rodent studies it restored muscle mass and bone density while stimulating the prostate far less than testosterone, which positioned it as a candidate for muscle wasting and osteoporosis. It was never approved for human use, and its documentation comes largely from preclinical pharmacology and anti-doping detection studies rather than completed clinical trials; it is prohibited in sport.

Andarine occupies an interesting place in the history of drug discovery as one of the compounds that proved the SARM concept, showing that a molecule could act as a strong anabolic agonist in muscle and bone while behaving as only a weak partial agonist in androgenic tissue. Researchers still cite its rodent data as a striking demonstration of tissue selectivity. Among users in the fitness community it has a mixed reputation; some report gains in strength and leanness, but it is honestly an unapproved, unfinished research chemical, notorious for a temporary yellow-tinged or impaired night vision and for suppressing the body's own testosterone. Its enduring scientific value lies more in what it taught about androgen-receptor biology than in any established therapeutic role.