Research use only

How does FDA decide a "research" peptide is really a drug?

By objective intent. Federal regulation says intended use can be shown by labeling claims, advertising, oral or written statements, or the circumstances in which a product is offered or used [2]. In its August 2026 letter to Peptide Partners, FDA wrote that despite labeling "for research use only" and "not for human or veterinary use," evidence from the company's website established the products were intended as drugs for human use [1]. Selling bacteriostatic water as a solvent for reconstitution counted as providing the means to prepare an injectable drug [1].

What products were involved?

The Peptide Partners letter named semaglutide, tirzepatide, retatrutide, elamipretide, tesamorelin and bremelanotide, all sold under research-style names [1]. FDA cited website claims about bone health, metabolism and neuroprotection as evidence of drug intent, and charged the company with marketing unapproved new drugs [1]. A 2026 review describes this direct-to-patient "gray market" as operating largely outside regulatory oversight, with scarce human safety data [3].

Is a research-use-only peptide the same as a compounded peptide?

No. A compounded peptide is prepared by a licensed pharmacy under section 503A or 503B rules for a patient. An RUO product is sold without a prescription, outside those rules, and with no FDA verification of what is in the vial. Neither is FDA-approved.