SARMs — selective androgen receptor modulators — remain among the most viral performance compounds in fitness and biohacking spaces, promoted for muscle gain and fat loss as a supposedly milder alternative to anabolic steroids. In reality they are unapproved drugs. In December 2025 the FDA issued a fresh batch of warning letters to companies selling products described as 'MK-2866' (ostarine/enobosarm), 'RAD-140' (testolone), 'LGD-4033' (ligandrol), 'S-4' (andarine) and 'YK-11', stating that marketing them into interstate commerce violates the Federal Food, Drug, and Cosmetic Act.
The core regulatory point is that SARMs are neither approved drugs nor lawful dietary-supplement ingredients, regardless of 'research use only' labelling. The FDA has repeatedly said products containing SARMs have been linked to life-threatening reactions, including liver toxicity, and its consumer messaging lists heart attack, stroke, psychosis and testicular effects among reported harms.
The liver signal is not hypothetical. Peer-reviewed case reports document drug-induced liver injury in previously healthy young men after weeks of self-administered RAD-140 and other SARMs, some with cholestatic patterns confirmed on biopsy. Adulteration compounds the problem: analytical studies of products sold as SARMs have found mislabelled contents, undeclared drugs and doses inconsistent with the label, so a buyer often does not know what is actually in the vial or capsule.
Enforcement extends beyond letters. In 2025 a US supplement company and its owner pleaded guilty to unlawful distribution of SARMs, and Health Canada seized unauthorised ostarine and RAD-140 products, warning of serious health risks. The trend and the crackdown are moving in parallel: virality has not changed the compounds' legal status or their documented hepatotoxicity.