SARMs: Compound Reference

Ostarine (MK-2866, enobosarm) is the most studied SARM with Phase II and III clinical trial data in cancer cachexia and muscle wasting. It is the most common entry-point SARM in the bodybuilding community due to its relatively mild side-effect profile compared to other SARMs.

Effects: Dose-dependent suppression of total testosterone and SHBG, HDL reduction, mild-moderate elevation of liver enzymes (rare DILI case reports), mild water retention, increased lean mass and strength relative to baseline

LGD-4033 (ligandrol) is a non-steroidal SARM developed by Ligand Pharmaceuticals for muscle wasting and osteoporosis. It has the highest number of published drug-induced liver injury (DILI) case reports of any SARM and produces significant HPTA suppression even at low doses.

Effects: Significant dose-dependent suppression of total testosterone, SHBG, and HDL, elevated liver enzymes with potential for cholestatic DILI, increased lean mass, moderate water retention

RAD-140 (testolone) is a non-steroidal SARM originally developed by Radius Health for breast cancer and muscle wasting. It carries the highest hepatotoxicity risk per published case report of any SARM, with a steroidal-like pattern of liver injury, and produces severe HPTA suppression.

Effects: Severe suppression of total testosterone, SHBG, LH, and FSH; significant HDL reduction; high risk of cholestatic drug-induced liver injury with elevated ALT, AST, ALP, and bilirubin; increased lean mass and strength

S-23 is a non-steroidal SARM with no human clinical trial data. It is the most potently suppressive SARM currently known, studied in animal models as a male hormonal contraceptive. All available human use data is anecdotal. It is considered completely experimental in humans.

Effects: Near-complete suppression of testosterone, LH, and FSH (castrate-level suppression in animal models), hardening and drying effect on body composition, unknown hepatotoxicity profile in humans, unknown long-term safety profile

YK-11 is a synthetic steroidal compound (a norpregnadiene derivative) that acts as a partial androgen receptor agonist and myostatin inhibitor via follistatin upregulation. It is not structurally a classic non-steroidal SARM. No human clinical trials exist. It is entirely experimental.

Effects: Unknown HPTA suppression in humans (likely significant given steroidal backbone), likely hepatotoxic due to steroidal and potentially methylated structure, myostatin inhibition via follistatin upregulation in vitro, increased lean mass (anecdotal)

Andarine (S-4) is one of the earlier non-steroidal SARMs developed by GTx Inc. It is known for a unique and dose-dependent visual side effect: yellow-tinted vision and difficulty adjusting to darkness, caused by binding to androgen receptors in the retina. This side effect is reversible on cessation.

Effects: Mild-moderate suppression of testosterone and SHBG, HDL reduction, mild elevation of liver enzymes, dose-dependent reversible yellow-tinted vision and impaired dark adaptation

Cardarine (GW-501516) is a PPARdelta (peroxisome proliferator-activated receptor delta) agonist, not a SARM. It does not bind androgen receptors and has no HPTA-suppressive activity. It is grouped with SARMs in the bodybuilding community due to co-administration and similar market positioning. Clinical development was abandoned after multi-organ tumour formation in rodent studies.

Effects: No testosterone suppression (non-androgenic mechanism), improved HDL, reduced triglycerides and LDL, enhanced fatty acid oxidation and endurance, improved insulin sensitivity, theoretical cancer risk extrapolated from rodent carcinogenicity data