Industry Record

FDA Peptide Warning Letters (2024 to 2026): Every Online Seller Named, and What Each Letter Says

Published: September 1, 2026

By the Curo Research Team

An FDA warning letter is a written notice that the agency believes a company is violating the Federal Food, Drug, and Cosmetic Act, and it gives the recipient 15 working days to respond. Between February 7, 2024 and August 24, 2026, FDA published 15 warning letters to online research-peptide storefronts. Two further letters in the same March 2026 batch went to eBay sellers of a patch and an oral solution rather than to research-vial storefronts, so this page counts those separately and reports 15 rather than 17. The newest storefront letters are dated August 24, 2026, to Peptide Partners LLC and NuScience Peptides LLC. This page is updated as FDA posts new letters, and every row links the letter on fda.gov so you can read the source. If you are checking a supplier's documentation rather than its enforcement record, start with lot-specific certificates of analysis and the compound listings in the product catalog.

TL;DR

FDA published 15 warning letters to online research-peptide storefronts between February 7, 2024 and August 24, 2026, plus 2 letters to eBay sellers of consumer-format GLP-1 products.
The largest single batch landed on March 31, 2026: seven letters, six of them to storefronts using coded product names such as "GLP-3 RT" and "GLP-2 TZ".
The most recent letters, dated August 24, 2026, went to Peptide Partners LLC of Sarasota, Florida and NuScience Peptides LLC of Cornelius, North Carolina.
FDA rejects "research use only" as a defense. Under 21 CFR 201.128 the agency reads the entire website, including linked forums and social accounts, to establish intended use.
As of September 1, 2026, FDA has published no closeout letters for any of the 15 storefront recipients.

Which peptide vendors have received FDA warning letters?

Fifteen online research-peptide storefronts received FDA warning letters between February 7, 2024 and August 24, 2026. The table below lists each one, newest first, with the products FDA named and the letter itself. Every letter cited unapproved new drug charges, and most added misbranding charges under section 502(f)(1) for lack of adequate directions for use.

Date	Recipient	Products named	What FDA cited	Letter
2026-08-24	Peptide Partners LLC (Sarasota, FL)	GLP-1 S (Semaglutide), GLP-2 T (Tirzepatide), GLP-3 Reta (Retatrutide), SS-31 (Elamipretide), Tesa (Tesamorelin), PT-141 (Bremelanotide), Reconstitution Solution	Website review July 2026; coded product names decoded in the letter	Read the letter
2026-08-24	NuScience Peptides LLC (Cornelius, NC)	GLP-2 Tirz, GLP-1 Sema, GLP-3 RT (Retatrutide), Survodutide, Mazdutide, PT-141, Tesamorelin, Tesamorelin Ipamorelin Blend, BAC Water	Website review July 2026	Read the letter
2026-06-17	Wholesale Peptide (Brooksville, FL)	Prostamax, Gonadorelin	Website review May 2026; new letter template	Read the letter
2026-03-31	PekCura Labs (Pensacola, FL)	"GLP-1-S", "GLP-2-T", "GLP-3-R", Bacteriostatic Water	Product pages quoted published human trial outcomes including HbA1c and a 24.2% body weight reduction	Read the letter
2026-03-31	Prime Sciences (Scottsdale, AZ)	Cagrilintide, "GLP1-R", "GLP1-S", "GLP1-T", Mazdutide, BAC water	Sold a "Reconstitution Kit" with water and syringe; claimed "potential in diabetes management and obesity treatment"	Read the letter
2026-03-31	Mile High Compounds LLC (Clifton, CO)	"GLP-1 SM", "GLP-2 TRZ", "GLP-3 RT", BAC Water	Site linked a Skool community forum whose "cheat sheet" carried dosing and titration; FDA treated the linked forum as labeling	Read the letter
2026-03-31	Lovega LLC dba Pink Pony Peptides (Wellington, FL)	"GLP-2 TZ", "GLP-3 RT", Bacteriostatic Water	Site copy said the products "reduce appetite" and "torch fat"; bacteriostatic water sold alongside	Read the letter
2026-03-31	Gram Peptides (Rancho Santa Fe, CA)	Retatrutide ("GLP-1-R"), Tirzepatide ("GLP-2"), Bacteriostatic Water for Injection	Coded product names; bacteriostatic water sold alongside treated as evidence of intended injection	Read the letter
2025-02-26	USApeptide.com (Germany)	Semaglutide, Tirzepatide	Brand-name comparisons to Ozempic; unapproved and misbranded, citing 301(a), (d), (k), 503(b) and 505(a)	Read the letter
2024-12-10	Swisschems (swisschems.is)	Semaglutide, Retatrutide	"Promising anti-obesity" claims; Facebook and Instagram accounts directing to the store	Read the letter
2024-12-10	Xcel Research LLC (Sheridan, WY)	Retatrutide, CagriLean, Cagrilintide, Mazdutide, Semaglutide, Survodutide, Sermorelin	"Weight management" and "enhanced insulin sensitivity" claims	Read the letter
2024-12-10	Prime Vitality, Inc. dba Prime Peptides (Santa Barbara, CA)	Semaglutide, Retatrutide	Product page quoted SELECT trial cardiovascular results; Facebook, Instagram and YouTube accounts	Read the letter
2024-12-10	Summit Research Peptides (Hoover, AL)	Semaglutide, Retatrutide, Cagrilintide, Tirzepatide, Mazdutide	Claimed "therapeutic applications in type 2 diabetes and obesity"; Facebook page directing to the store	Read the letter
2024-02-07	Synthetix Inc. dba Helix Chemical Supply (Bronx, NY)	Semaglutide, Tirzepatide	Dosing schedule on the product page ("Weeks 1-4 - 8 doses"), Alzheimer's and blood sugar claims; misbranded	Read the letter
2024-02-07	US Chem Labs	Semaglutide, Tirzepatide, Thymalin	Weight-loss, stroke and heart-attack claims; thymalin marketed for adults and children; misbranded under 502(f)(1)	Read the letter

Two more letters dated March 31, 2026 went to eBay sellers rather than research-vial storefronts, which is why they sit outside the table. FDA wrote to FormPour of Canton, Michigan over an eBay listing for a "SMGT-GLT-1 Nano Microneedle Patch", and to Guangzhou Huli Technology Co. dba Fantasy Face of Chicago, Illinois over an eBay listing for a "Googeer GLP-1 Weight Control Oral Solution". Both are consumer-format products sold on a marketplace, not vials sold as research chemicals, so counting them alongside the storefronts would overstate the storefront total.

What do the FDA warning letters to peptide sellers actually say?

The 15 storefront letters repeat six findings. FDA states that a "research use only" label does not control intended use, and that the agency reads the whole website under 21 CFR 201.128. Each pattern below appears in multiple letters.

FDA regards bacteriostatic water sold alongside peptide vials as evidence that the seller intends the peptides for injection, and the water itself becomes a drug. Gram Peptides, Pink Pony Peptides, Mile High Compounds, Prime Sciences, PekCura Labs and NuScience Peptides all listed bacteriostatic water or a reconstitution product.
FDA decodes coded product names in the letter itself. Names such as "GLP-3 RT", "GLP1-R" and "GLP-2 Tirz" are matched to retatrutide, semaglutide and tirzepatide, and the analysis proceeds unchanged.
FDA counts linked forums as labeling. The Mile High Compounds letter cites a Skool community forum reached from the website whose "cheat sheet" carried dosing and titration information.
FDA counts social accounts as labeling. The Summit Research Peptides, Prime Peptides and Swisschems letters all name Facebook, Instagram or YouTube accounts that directed visitors to the store.
FDA regards quoted human clinical-trial outcomes as intended-use evidence. The PekCura Labs letter cites product pages quoting HbA1c results, a 24.2% body weight reduction and cardiovascular endpoints; the Prime Peptides letter cites SELECT trial cardiovascular results.
FDA gives each recipient 15 working days to respond. As of September 1, 2026, the agency has published no closeout letter for any of the 15 storefront recipients.

Does a "research use only" label make a peptide website legal?

No. FDA has rejected the "research use only" label in every storefront warning letter in this record. Under 21 CFR 201.128, intended use is established by the seller's objective conduct, which includes product page copy, product names, linked forums, social accounts and what else is sold in the same cart. A disclaimer does not override that evidence. FDA also used the phrase "falsely labeled for research purposes" in its public statement on unapproved GLP-1 drugs. The label still matters as a statement of what a product is sold for, which is why Curo publishes its research use only policy, but it is not a legal shield for a site that markets human outcomes.

Are the warned vendors still selling?

Most of them are. A census published by PeptidePrices on August 23, 2026 counted 13 storefront warning letters from February 2024 through June 2026 and found that 10 of the 13 recipients were still selling, either on a public site or behind an account gate. That census predates the two August 24, 2026 letters, so it does not cover Peptide Partners or NuScience Peptides. FDA has published no closeout letters for any storefront recipient as of September 1, 2026, so the public record shows no resolved case. Beyond the census figure, this page does not assert the current status of any individual vendor; site availability changes without notice and a live site is not evidence that a matter is closed.

How to check a peptide vendor against the FDA warning-letter database

Open the FDA warning letter search.
Search the company's legal name and any "dba" name. Several recipients in this record were addressed under a corporate name that does not appear on the storefront, such as Lovega LLC for Pink Pony Peptides and Prime Vitality, Inc. for Prime Peptides.
Search the domain name on its own, since FDA addressed at least one recipient by website, as with USApeptide.com.
Read the letter's "Issuing Office" and response section, then check whether a closeout letter exists. No closeout letter means the matter is not publicly resolved.

Two letters in this window went to adjacent businesses rather than peptide storefronts. FDA wrote to Atomix LLC of Sheridan, Wyoming on December 12, 2025 over SARMs including MK-2866 and RAD-140, again rejecting the research use only label, and to GenoGenix LLC of Boca Raton, Florida on January 20, 2026 over sterility failures at a 503B outsourcing facility that recalled product and ceased production. Civil litigation runs alongside the letters: Reuters reported on August 12, 2026 that Eli Lilly sued six companies over alleged illegal sales of an experimental obesity drug. For criminal and vendor-failure records, see the Paradigm Peptides federal case, the documented record on Amino Asylum, and what happened to Peptide Sciences.

Where Curo stands

Curo has not received an FDA warning letter, and that is a statement about the public record on September 1, 2026, not a claim of approval or immunity from enforcement. Curo sells peptides for laboratory research use only and publishes lot-specific certificates of analysis tied to the vial you receive, along with the quality and testing standard that describes how those lots are tested and by whom. The catalog of research compounds carries no dosing instructions and no benefit copy, because the letters in this record show that product-page claims are what FDA reads. Curo does not bundle bacteriostatic water, syringes, or injection instructions with peptides, and does not operate a linked forum where that material could sit instead. Orders are fulfilled from the United States.

Common questions

How many FDA warning letters have peptide vendors received? FDA published 15 warning letters to online research-peptide storefronts between February 7, 2024 and August 24, 2026, as counted from the agency's published letters on September 1, 2026. Two additional letters dated March 31, 2026 went to eBay sellers of a microneedle patch and an oral solution, which brings the wider total to 17 if marketplace listings are included.

What happens after an FDA warning letter? The recipient has 15 working days to respond in writing describing the corrections made and the steps taken to prevent a recurrence. FDA may then issue a closeout letter, take further action such as seizure or injunction, or take no public step at all. As of September 1, 2026, no closeout letter has been published for any of the 15 storefront recipients in this record.

Is bacteriostatic water illegal to sell with peptides? Bacteriostatic water is not banned, but FDA treated its sale alongside peptide vials as evidence of intended injection in the March 31, 2026 letters to Gram Peptides, Pink Pony Peptides, Mile High Compounds, Prime Sciences and PekCura Labs. In those letters the water itself was also treated as an unapproved drug because of how it was marketed with the vials.

Does an FDA warning letter shut a peptide company down? No. A warning letter is a notice of alleged violations, not a closure order, and it carries no automatic penalty. The PeptidePrices census of August 23, 2026 found 10 of 13 storefront recipients still selling. FDA can escalate to injunction, seizure or referral for prosecution if a recipient does not correct the violations it identified.