Dangers of Injectable Peptides and Other Unregulated "Biohacking" Drugs.

Injectable peptides are increasingly used without prescriptions for cosmetic and athletic enhancement, driven by digital marketing and social media. While evidence-based, FDA-approved peptides like semaglutide and tirzepatide offer significant clinical benefits under medical supervision, an expanding illicit market provides easy access without a prescription to many unapproved experimental drugs. These unregulated substances-including the veterinary anabolic steroid trenbolone, investigational triple-agonists like retatrutide, and unapproved peptides such as BPC-157, TB-500, and melanotan-II-lack established human safety profiles. Their use introduces severe potential risks, including product contamination, manufacturing impurities, inaccurate dosing, pathological angiogenesis, carcinogenesis, cardiovascular stress, and supraphysiological hormonal signaling. This review differentiates evidence-based therapeutics from unproven, high-risk compounds and outlines the molecular mechanisms of toxicity associated with popular "looksmaxxing" injectables. Clinicians must recognize these trends, and counsel patients on potential long-term health hazards of these potent agents.