Partnership for Safe Medicines compiles FDA's research-chemical warning letters
A safe-medicines group posted FDA's March 31, 2026 warning letters to peptide sellers, showing how sites rebrand tirzepatide as "GLP-2" and retatrutide as "GLP-3" while calling them research chemicals [1].
The Partnership for Safe Medicines has posted a compilation of recent Food and Drug Administration warning letters aimed at online "research chemical" peptide sellers, giving consumers a single place to see which companies the agency has cited over tirzepatide, retatrutide and related injectable products [1].
The compilation, dated April 7, 2026, includes letters issued March 31, 2026 by FDA's Center for Drug Evaluation and Research to Lovega LLC, doing business as Pink Pony Peptides, of Wellington, Florida (case number 721088); Gram Peptides of Rancho Santa Fe, California (721806); and Mile High Compounds LLC of Clifton, Colorado (721600) [1]. Each letter was delivered by email and signed by Tina Smith, director of FDA's Office of Unapproved Drugs and Labeling Compliance [1].
What FDA said
In the Pink Pony Peptides letter, FDA said it reviewed the company's website in December 2025 and found it offering "GLP-2 TZ," "GLP-3 RT" and "Bacteriostatic Water" for sale in the United States [1]. The agency said the products are unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act, and that shipping them in interstate commerce violates sections 301(d) and 505(a) [1].
The letters lay out how the agency treats "research use only" labeling. Despite statements that products were for "laboratory research purposes only" and "[n]ot for human consumption," FDA said the websites' own marketing established that the products were intended as drugs for people [1]. The agency quoted the Pink Pony Peptides site describing tirzepatide as a "dual GIP and GLP-1 receptor agonist" that helps "[r]educe appetite and increase satiety" and "[s]upport fat loss over time with clinical precision," and describing retatrutide as offering "three times the fat-fighting horsepower in one clean, clinical ride" [1].
FDA said it reviewed grampeptides.com from January to March 2026 and found "Retatrutide" sold as "GLP-1-R peptide," "Tirzepatide" sold as "GLP-2 peptide," and "Bacteriostatic Water for Injection" [1]. Quoted marketing claimed the tirzepatide product was "[a]ssociated with significant decreases in body weight in both animal and human studies" and showed "reductions in triglycerides and improved cholesterol ratios" [1]. Gram Peptides labeled its items "Research Use Only" and "not intended for human consumption, medical use, or veterinary use" [1].
Notably, FDA also treated the bacteriostatic water itself as a drug in both letters, reasoning that selling it alongside peptides that require reconstitution shows it is intended for injection [1].
The agency called injectable products "especially concerning from a public health perspective" because they are delivered directly into the body and "bypass some of the body's key defenses against toxins and microorganisms that can lead to serious and life-threatening conditions" [1]. FDA said no approved applications under section 505 are in effect for these products [1].
Why it matters for patients
The naming conventions described in the letters are the practical takeaway. Products marketed online as "GLP-2," "GLP-2 TZ," "GLP-1-R" or "GLP-3 RT" are, by the sellers' own product pages, tirzepatide and retatrutide [1]. That labeling can make gray-market vials hard to recognize for someone comparing prices against prescription products.
FDA's position is that a "research use only" disclaimer does not change what a product is when the marketing around it promotes weight loss and blood sugar effects [1]. The letters also make clear that these items have not gone through FDA approval, so their contents, strength and sterility have not been reviewed by the agency [1].
What happens next
Each letter gives the company 15 working days from receipt to tell FDA in writing what steps it has taken to correct the violations, or to explain why it believes the products do not violate the law [1]. FDA warned that failure to adequately address the issues "may lead to regulatory or legal action including, without limitation, seizure and injunction" [1].
The specific allegations in the Mile High Compounds letter, along with any responses from the three companies, have not been reported.
Sources
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