FDA warning letter to Gram Peptides citing tirzepatide
FDA told a California peptide seller that "research use only" labels don't shield tirzepatide and retatrutide sold online, in a March 31, 2026 warning letter [1].
The U.S. Food and Drug Administration issued a warning letter on March 31, 2026 to Gram Peptides of Rancho Santa Fe, California, and its named recipient Bernard Gramlich, saying the company's online sales of "Retatrutide," "Tirzepatide" and "Bacteriostatic Water for Injection" are unapproved new drugs under federal law [1]. The agency said the products' "Research Use Only" disclaimers do not control, because the rest of the website marketing shows the products are intended for human use [1].
What the letter says
FDA reviewed the website grampeptides.com from January to March 2026 [1]. The letter states the site offered retatrutide, which the firm also called "GLP-1-R peptide," and tirzepatide, which the firm also called "GLP-2 peptide," for sale in the United States [1]. Both names are unusual: tirzepatide is the molecule in the FDA-approved products Mounjaro and Zepbound, and "GLP-2" is not how it is normally described.
According to the letter, the retatrutide page said the compound "[i]nfluences appetite suppression, insulin sensitivity, thermogenesis, and fat-oxidation models" and "[d]emonstrated significant potential for reducing body weight, improving glucose handling, and enhancing lipid metabolism" [1]. The tirzepatide page listed benefits including "Metabolic Regulation," "Weight Management – Associated with significant decreases in body weight in both animal and human studies," and "Improved Lipid Profiles" [1].
FDA said those claims make the products drugs under section 201(g)(1) of the Federal Food, Drug, and Cosmetic Act, because they are intended to treat disease or affect the structure or function of the body [1]. They are "new drugs" because they are not generally recognized as safe and effective for those uses, and no approved applications are in effect for them, so shipping them in interstate commerce violates sections 301(d) and 505(a) of the law [1].
The bacteriostatic water point
One part of the letter is notable for how it treats a product that, on its own, is just sterile water with a preservative. FDA said Gram Peptides offers "Bacteriostatic Water for Injection" for sale alongside peptide products that are intended for injection and require reconstitution, including the two GLP products [1]. "The sale of these products together demonstrates that you intend for your 'Bacteriostatic Water for Injection' to be used in combination for injection," the letter says, concluding that the water is therefore also a drug [1].
In other words, the agency looked at the whole storefront — the claims, the product pairings, the practical steps a buyer would take — rather than the disclaimer text. The letter states plainly that despite labeling saying the products are "not intended for human consumption, medical use, or veterinary use," website evidence establishes that they are intended to be drugs for human use [1].
FDA also flagged the injection route itself as a public health concern, writing that injectable products are "delivered directly into the body, sometimes directly into the bloodstream, and therefore, bypass some of the body's key defenses against toxins and microorganisms that can lead to serious and life-threatening conditions" [1].
Why it matters for patients
Gray-market peptide sites have become a common workaround for people priced out of brand-name GLP-1 medicines. This letter is a clear statement of how FDA reads those sites: the "research use only" language is not a legal shield when the surrounding marketing, including selling mixing water next to the vials, points to human injection [1].
For a consumer, the practical gap is quality assurance. These products have no approved application on file, which means FDA has not reviewed their identity, strength, purity or sterility for the uses being suggested [1]. The letter does not report any testing results for Gram Peptides' vials, any contamination findings, or any injuries — none of that is in this document. It also does not say how many customers bought the products.
Retatrutide is not an approved medicine in the United States, and this letter does not change that. Tirzepatide is approved, but only in FDA-reviewed products, not as a research chemical sold by the vial.
What happens next
FDA asked the firm to respond in writing within 15 working days of receiving the letter, describing the specific steps taken to correct the violations and prevent recurrence, or explaining why it believes the products do not violate the law [1]. Responses go to CDER's Office of Unapproved Drugs and Labeling Compliance, with the identifier "721806" in the subject line [1].
The letter warns that failure to adequately address the issues "may lead to regulatory or legal action including, without limitation, seizure and injunction" [1]. FDA also noted the listed violations are not meant to be a complete accounting of everything that may be wrong with the products [1]. Whether Gram Peptides has responded, and what it said, is not yet known from the available source.
Sources
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