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Selective androgen receptor modulators; the research compounds studied for muscle and recovery, with the honest evidence and sourcing.
14 sourced · 7 reference
LGD-3303 is a non-steroidal selective androgen receptor modulator (SARM) that stands out for its pronounced effects on bone as well as muscle. In rodent studies it raised bone mineral density, stimulated new bone formation, and increased muscle mass while keeping prostate stimulation low, and it even added to the benefit of a standard bone drug. Orally active and strongly tissue-selective, LGD-3303 has a distinctive physique-and-bone profile that keeps it firmly on the radar of SARM research.
LGD-4033 + YK-11 is a research stack that pairs Ligandrol (LGD-4033), a selective androgen receptor modulator, with YK-11, a myostatin-modulating compound, to pursue muscle growth through two mechanisms at once. LGD-4033 activates the androgen receptor and has increased lean body mass in a human trial, while YK-11 raises follistatin to counteract myostatin, the natural brake on muscle growth. For researchers exploring maximal anabolic signaling, this dual-mechanism combination is a frequently discussed and potent pairing.
AC-262536, also written AC-262,536, is a nonsteroidal selective androgen receptor modulator (SARM) first characterized by Acadia Pharmaceuticals. It acts as a partial agonist of the androgen receptor and was studied preclinically for its tissue-selective anabolic profile, producing muscle-building effects while showing comparatively weak activity on reproductive tissue such as the prostate.
ACP-105 is a potent nonsteroidal selective androgen receptor modulator (SARM) engineered to deliver the muscle- and bone-building benefits of androgens with greater tissue selectivity than testosterone. As a partial agonist at the androgen receptor, it was designed to drive anabolism in muscle and bone while limiting the unwanted effects tied to classic steroids. Its combination of anabolic potency and an intriguing signal for cognitive and neuroprotective effects has made it a standout among research-grade SARMs.
Andarine (S-4) is a non-steroidal selective androgen receptor modulator derived from arylpropionamide chemistry that binds the androgen receptor with high affinity yet acts in a tissue-selective manner. In castrated and ovariectomized rodents it restored skeletal muscle mass and strength, raised bone mineral density, and reduced body fat while stimulating the prostate and seminal vesicles far less than dihydrotestosterone; this partial-agonist behavior in androgenic organs versus full-agonist activity in muscle and bone defines the SARM concept. Its favorable pharmacokinetics, including high oral bioavailability and predominantly hepatic phase I and II metabolism, once positioned it as a clinical candidate for muscle wasting and osteoporosis. It was never approved for human use, however, and is prohibited in sport, so it is documented largely through preclinical pharmacology and anti-doping detection studies rather than clinical trials.
GSK-2881078 is one of the best-documented SARMs in humans, which alone sets it apart in a class full of guesswork. Developed by GlaxoSmithKline as a non-steroidal, tissue-selective androgen receptor agonist, it produced clean, dose-dependent gains in lean mass in older men and women and was carried into a controlled trial in patients with COPD. For anyone seeking a selective androgen receptor modulator with genuine clinical evidence and a real pharmaceutical pedigree, GSK-2881078 sits near the top of the list.
LGD-2226 is a first-generation selective androgen receptor modulator (SARM) developed to build muscle and bone with far less impact on the prostate than traditional androgens. In animal studies it increased muscle and bone mass and enhanced bone strength while sparing the prostate and preserving male sexual behavior, showcasing the tissue selectivity that defines the SARM class. Orally active and non-steroidal, LGD-2226 is a notable early example of the effort to capture the benefits of androgens while minimizing their drawbacks.
LGD-4033, also known as ligandrol or VK5211, is an investigational nonsteroidal selective androgen receptor modulator, a class of compounds abbreviated as SARM. It binds the androgen receptor, the same target acted on by testosterone, but is designed to stimulate muscle and bone while having weaker effects on other tissues. First described by Ligand Pharmaceuticals and later developed by Viking Therapeutics, it has been studied for muscle wasting but is not approved for any medical use, and it is banned in sport and sold illicitly to bodybuilders.
Ostarine, known in drug development as enobosarm or MK-2866, is an investigational selective androgen receptor modulator (SARM). SARMs are compounds designed to stimulate the androgen receptor in a tissue-selective way, aiming to build muscle and bone like anabolic steroids but with fewer effects on organs such as the prostate. Ostarine has been studied mainly for the muscle wasting associated with cancer and related conditions, but it is not approved as a medicine anywhere; it is prohibited in sport and has been the subject of regulatory warnings over its sale in bodybuilding and supplement products.
OTR-AC is an acetate ester of ostarine (enobosarm), the most clinically characterized selective androgen receptor modulator (SARM) in development. It is designed to deliver enobosarm's muscle-selective, orally active anabolic signal, building lean mass and physical function while sparing the prostate and other tissues that traditional androgens affect [3][4]. In controlled trials, enobosarm consistently increased lean body mass in older adults and cancer patients [1][2], and the acetate ester form is marketed as more potent per milligram.
RAD-150 (TLB-150 Benzoate) is a research chemical marketed as an ester form of the popular SARM RAD-140 (Testolone), promoted for building muscle and strength with a potentially longer-acting profile [1]. Like other selective androgen receptor modulators, it is intended to stimulate the androgen receptor in muscle and bone, but RAD-150 itself has no published pharmacological or clinical studies, so its profile is inferred from RAD-140 and the broader SARM class [1]. It is an unapproved, WADA-banned research chemical, and the RAD-140 family it is based on has been linked in case reports to serious cardiovascular harm [1][2][3].
S-23 is a high-affinity, orally active selective androgen receptor modulator (SARM) first characterized as a candidate for hormonal male contraception. It binds the androgen receptor as a full agonist and, in animal studies, builds lean muscle mass and bone mineral density while cutting fat, a tissue-selective anabolic profile that has drawn strong interest for body recomposition. It also potently and reversibly suppresses testosterone and sperm production, which is central to both its contraceptive rationale and its cautions.
RAD-140, also known as testolone, is an experimental selective androgen receptor modulator, or SARM, a class of nonsteroidal compounds designed to stimulate muscle and bone growth while causing fewer of the unwanted effects of anabolic steroids. It was created by a pharmaceutical company as a potential treatment for conditions such as muscle wasting and, later, hormone-sensitive breast cancer, but it has not been approved for any medical use. Despite this, it is sold online and misused for bodybuilding, a practice associated with reports of liver and heart injury, and it is banned in sport by anti-doping authorities.
YK-11 is a synthetic steroidal SARM (selective androgen receptor modulator) famous in bodybuilding circles as a myostatin inhibitor, prized for its potential to push muscle growth past the body's natural limits. Uniquely among SARMs, it drives muscle cells to produce follistatin, a protein that blocks myostatin, the built-in brake on muscle size. This dual action as both an androgen receptor activator and a follistatin booster has made YK-11 one of the most talked-about compounds for lean mass, though it remains an experimental, unapproved research chemical.
RAD-140 (Testolone) plus YK-11 is a popular bodybuilding stack that pairs two selective androgen receptor modulators (SARMs) sought for rapid gains in muscle mass and strength [1]. RAD-140 is a potent nonsteroidal androgen receptor agonist designed to drive muscle growth with fewer of the prostate and hormonal effects of testosterone, while YK-11 is a steroidal SARM marketed as a myostatin-modulating muscle-builder [1][7]. Both are investigational research chemicals, not approved drugs, and both are banned in sport; importantly, RAD-140 has been linked in case reports to serious cardiac harm, so the stack carries real risk [1][2][3].
Arcarine is a non-steroidal selective androgen receptor modulator (SARM) developed by the Finnish company Orion Corporation. It was investigated for tissue-selective anabolic applications such as bone formation, but development was discontinued.
BMS-564929 is a nonsteroidal selective androgen receptor modulator (SARM) developed by Bristol-Myers Squibb as an orally active candidate for age-related decline in muscle and strength. In laboratory studies it behaves as a potent androgen receptor agonist that favors skeletal muscle over the prostate, a tissue selectivity intended to separate the anabolic benefits of androgens from unwanted prostate stimulation. It advanced into early clinical testing but was never approved, and, like other SARMs, it has been prohibited in sport since 2008.
GLPG-0492 is an experimental non-steroidal selective androgen receptor modulator (SARM) developed by the pharmaceutical company Galapagos. In preclinical studies it acted as a partial agonist of the androgen receptor, producing anabolic effects on skeletal muscle while largely sparing the prostate, and it was investigated for muscle-wasting conditions such as cachexia and Duchenne muscular dystrophy [1][2][4]. It advanced into early clinical evaluation but has not been approved for use as a medicine.
GSK-2849466 is an experimental non-steroidal selective androgen receptor modulator (SARM) developed by GlaxoSmithKline. It was evaluated in an early-stage, phase I clinical trial that assessed its safety, tolerability, and pharmacological behavior in healthy men, in the context of possible use for muscle-wasting conditions such as cachexia [1][2]. It did not become an approved medicine and remains a research compound.
GSK-971086 is an experimental non-steroidal selective androgen receptor modulator (SARM) developed by GlaxoSmithKline. It was tested in an early-stage, phase I clinical trial that examined its safety, tolerability, and pharmacokinetics in healthy men, with a view to conditions involving androgen deficiency and loss of muscle [1][2]. It did not reach approval and remains investigational.
GTX-027 is described as an experimental selective androgen receptor modulator (SARM) associated with GTx, the company behind better-known compounds of this class such as enobosarm (ostarine) and andarine. Publicly verifiable information specific to GTX-027 is extremely limited; under that designation it does not appear in the indexed biomedical literature or in clinical-trial registries. It has not been approved and is best regarded as a thinly documented research designation within the SARM class [1][2][3].
