The Short Answer
Most research peptides (BPC-157, TB-500, CJC-1295, etc.) are legal to purchase in the US as research chemicals but are not legal to sell for human use. FDA-approved peptides (semaglutide, PT-141/Vyleesi, thymosin alpha-1 variants) are legal with a valid prescription. The line between legal and illegal is drawn by what claims are made, how the product is sold, and whether it's been approved by the FDA for human therapeutic use.
The Research Chemical Classification
Most peptides on this site fall under what is commonly called 'research chemical' status. This means they are legal to purchase and possess for scientific research purposes but cannot legally be marketed, sold, or labeled for human consumption. The FDA's position is that selling these compounds with claims like 'for muscle recovery' or 'take 200mcg before bed' constitutes selling an unapproved drug — which is a regulatory violation.
Compounded Peptides: The Gray Area
Compounding pharmacies have historically been able to produce certain peptides for prescriptions. However, in 2023–2024, the FDA added many popular peptides (including BPC-157 and TB-500) to its Category 2 list of 'Difficult to Compound' substances, effectively preventing compounding pharmacies from making them. This significantly affected the availability of high-quality compounded peptides through legitimate medical channels.
FDA-Approved Peptides
Some peptides have full FDA approval and are legal with a prescription. These include: Semaglutide (Ozempic/Wegovy), Tirzepatide (Mounjaro/Zepbound), PT-141/Bremelanotide (Vyleesi), Sermorelin (various brands), and several others. For these, the legal pathway is clear: see a licensed healthcare provider, get a prescription, fill it at a licensed pharmacy.