In the United States, most peptides that are intended to change how the body works are regulated as drugs by the FDA. That means they cannot legally be marketed as treatments for diseases unless they have been specifically approved by the FDA for that use.
Some peptides may be available through compounding pharmacies, but this is a tightly regulated area. Patient-specific prescriptions may be prepared by 503A pharmacies, while larger outsourcing facilities operate under 503B rules and must follow stricter manufacturing standards. Compounded peptides must also comply with FDA guidance, state pharmacy board rules, and restrictions on which ingredients may be used.
Marketing is another important issue. Companies and providers must be careful not to make unsupported claims about fat loss, muscle gain, anti-aging, longevity, or disease treatment. The FTC requires advertising to be truthful, evidence-based, and not misleading.
Peptide prescribing should happen through a legitimate doctor-patient relationship, with proper evaluation, informed consent, and medical follow-up. Because laws and enforcement can change, the safest approach is to use peptides only under qualified medical supervision, with clear documentation, appropriate lab monitoring, and realistic expectations.