Does a “research use only” label make peptides legal to sell?

How FDA decides what a product is for

The regulation on “intended uses,” 21 CFR 201.128, ties intent to the objective intent of the people legally responsible for the labeling. It says intent can be shown by labeling claims, advertising matter, and oral or written statements by those people or their representatives, and by the circumstances surrounding distribution.

The Federal Food, Drug, and Cosmetic Act defines a drug to include articles intended to treat or prevent disease or to affect the structure or function of the body (section 201(g)(1)). A “new drug” without FDA approval cannot be introduced into interstate commerce (sections 301(d) and 505(a)).

What FDA said in the Xcel Research letter

The letter is dated December 10, 2024. It names products including retatrutide, cagrilintide, semaglutide, mazdutide, survodutide and sermorelin. FDA noted that the products were labeled “for research use only” and “not intended for human use.” It said evidence from the company's website established that the products were intended as drugs for humans, citing website claims about weight management, glucose control and cardiovascular protection.

These are FDA's allegations in a warning letter, not court findings.

What this does not tell you

• It is not a court ruling about any company.
• It does not describe what any seller's site says today. Pages change.
• It does not decide whether a particular product is safe or effective.

How to read a story about a seller

• Find the claims the letter quotes from the seller's site and compare them with the label wording.
• Check the letter's issue date against the date FDA posted it, and against any archived copy of the site.
• Look for a company response or a close-out letter on FDA's page.