GHK-Cu Peptide COA: How to Evaluate Research-Grade Copper Peptides
September 24, 2026
A GHK-Cu peptide COA is one of the most useful documents researchers can review when
The FDA issued warning letters to multiple companies in 2026 after reviewing their websites, inspecting facilities, or identifying other regulatory violations involving peptide-related and drug products. In the cited cases, the FDA identified website claims, product presentation, intended use, manufacturing practices, or other regulatory issues that supported its findings.
This article highlights 14 companies that received FDA warning letters in 2026 involving peptide-related products and other products marketed for drug-like uses, including semaglutide, tirzepatide, retatrutide, cagrilintide, mazdutide, tesamorelin, PT-141, SS-31, gonadorelin, and bacteriostatic or reconstitution solutions and other peptide-related products. In the cited warning letters, FDA determined that specific products were unapproved new drugs, based on its review of product labeling, website claims, intended use, and related marketing practices.
The table below provides a quick overview of the companies discussed in this article, the dates of their FDA warning letter, and the primary products or regulatory issues identified by the agency.
| Company | FDA Letter Date | Main Products / Issues |
| GenoGenix LLC | January 20, 2026 | Semaglutide, tirzepatide, retatrutide, Thymosin Beta-4; unapproved drugs and unapproved biological products |
| Gram Peptides | March 31, 2026 | Retatrutide, tirzepatide, Bacteriostatic Water; website claims indicating human-drug use |
| Prime Sciences | March 31, 2026 | Cagrilintide, GLP1-R, GLP1-S, GLP1-T, mazdutide, BAC water; unapproved new drugs |
| PekCura Labs | March 31, 2026 | GLP-1-S, GLP-2-T, GLP-3-R, Bacteriostatic Water; unapproved new drugs |
| Lovega LLC dba Pink Pony Peptides | March 31, 2026 | GLP-2 TZ, GLP-3 RT, Bacteriostatic Water; website claims related to metabolic and weight-related effects |
| FormPour | March 31, 2026 | SMGT-GLT-1 Nano Microneedle Patch; claims involving Type 2 diabetes, weight loss, and cardiovascular protection |
| Guangzhou Huli Technology Co., Ltd. dba Fantasy Face | March 31, 2026 | Googeer GLP-1 Weight Control Oral Solution; weight management, blood sugar, metabolism, body-shaping claims |
| Mile High Compounds LLC | March 31, 2026 | GLP-1 SM, GLP-2 TRZ, GLP-3 RT, BAC Water; unapproved new drugs |
| Wholesale Peptide | June 17, 2026 | Prostamax and Gonadorelin; disease-related and physiological claims |
| Peptide Partners LLC | August 24, 2026 | Semaglutide, tirzepatide, retatrutide, SS-31, tesamorelin, PT-141, reconstitution solution |
| NuScience Peptides LLC | August 24, 2026 | Tirzepatide, semaglutide, retatrutide, survodutide, mazdutide, PT-141, tesamorelin, BAC water |
| Royal Peptides LLC | August 24, 2026 | Tirzepatide, semaglutide, retatrutide, SS-31, PT-141, tesamorelin, BIMORELIN |
| TXP Innovations LLC dba Tex Peptides | August 24, 2026 | Semaglutide, tirzepatide, retatrutide, SS-31, tesamorelin, PT-141, Bacteriostatic Water |
| Peak Performance Peptides | August 24, 2026 | BAC water, retatrutide, semaglutide, SS-31, PT-141, tesamorelin |
GenoGenix LLC received an FDA warning letter on January 20, 2026, following an FDA inspection of its facility in July 2025. FDA identified semaglutide, tirzepatide, retatrutide, and Thymosin Beta-4 and determined that the products were unapproved new drugs. The agency also identified Thymosin Beta-4 as an unapproved biological product.
On March 31, 2026, the FDA issued a group of warning letters involving peptide-related and GLP-1-marketed products. The companies included Gram Peptides, Prime Sciences, PekCura Labs, Lovega LLC dba Pink Pony Peptides, FormPour, Guangzhou Huli Technology Co., Ltd. dba Fantasy Face, and Mile High Compounds LLC. FDA determined that the specific products identified in these letters were unapproved new drugs under section 505(a) of the Federal Food, Drug, and Cosmetic Act.
FDA reviewed Gram Peptides’ website from January through March 2026 and identified retatrutide, tirzepatide, and Bacteriostatic Water for Injection. The agency stated that, although the products carried “Research Use Only” and “not intended for human consumption” language, evidence from the website established an intended use as drugs for human use. FDA also cited claims relating retatrutide to appetite suppression, insulin sensitivity, body-weight reduction, glucose handling, and lipid metabolism, while tirzepatide was associated with claims concerning glucose, insulin, weight management, and lipid profiles.
FDA’s March 31 letter to Prime Sciences identified cagrilintide, GLP1-R, GLP1-S, GLP1-T, mazdutide, and BAC water. FDA determined that these products were unapproved new drugs after reviewing the company’s website from January through March 2026.
For PekCura Labs, FDA identified GLP-1-S, GLP-2-T, GLP-3-R, and Bacteriostatic Water during its January 2026 review of the company’s website. The agency determined that these products were unapproved new drugs under section 505(a).
Lovega LLC, doing business as Pink Pony Peptides, received a March 31 warning letter covering GLP-2 TZ, GLP-3 RT, and Bacteriostatic Water. FDA had reviewed the company’s website in December 2025 and concluded that the products were unapproved new drugs.
FDA reviewed FormPour’s eBay store in December 2025 and identified an “SMGT-GLT-1 Nano Microneedle Patch” offered for sale in the United States. FDA cited website claims associating the product with Type 2 diabetes treatment, weight loss, and cardiovascular protection, and determined that the product was an unapproved new drug under section 505(a) of the FD&C Act.
Guangzhou Huli Technology Co., Ltd., doing business as Fantasy Face, received a March 31, 2026 warning letter after the FDA reviewed its eBay store in December 2025. FDA identified a “Googeer GLP-1 Weight Control Oral Solution” and cited claims concerning weight management, blood sugar balance, metabolism support, and body shaping. FDA determined that the product was an unapproved new drug under section 505(a) of the FD&C Act.
FDA reviewed the Mile High Compounds company’s website and its linked community forum from January through March 2026. The cited products were GLP-1 SM, GLP-2 TRZ, GLP-3 RT, and BAC Water, which FDA determined were unapproved new drugs.
On June 17, 2026, FDA issued a warning letter to Wholesale Peptide after reviewing the company’s website in May. The agency identified Prostamax and Gonadorelin as unapproved new drugs. FDA cited specific website claims for Prostamax concerning prostate inflammation, enlarged prostate, bladder control, benign prostatic hyperplasia, and prostatitis. For Gonadorelin, FDA cited statements concerning testosterone production, testicular function, spermatogenesis, and investigations involving hormone-dependent cancers.
This case demonstrates why the scientific topic itself is not necessarily the regulatory issue. FDA specifically evaluated the intended use of the products based on claims appearing on the company’s website, including claims about treating conditions and producing physiological effects.
A second significant group of peptide-company warning letters was issued on August 24, 2026. The companies were Peptide Partners LLC, NuScience Peptides LLC, Royal Peptides LLC, TXP Innovations LLC dba Tex Peptides, and Peak Performance Peptides. FDA’s warning-letter database lists these five August 24, 2026 actions under the enforcement category “Unapproved New Drugs/Misbranded.”
Peptide Partners’ letter identified semaglutide, tirzepatide, retatrutide, SS-31 (elamipretide), tesamorelin, PT-141 (bremelanotide), and a reconstitution solution. FDA stated that the reconstitution solution was also a drug because the company sold it to reconstitute products intended for injection.
NuScience Peptides received a letter covering tirzepatide, semaglutide, retatrutide, survodutide, mazdutide, PT-141, tesamorelin products, and bacteriostatic water. FDA again determined these were unapproved new drugs and specifically noted the sale of bacteriostatic water for reconstituting injectable peptide products.
Royal Peptides’ cited products included tirzepatide, semaglutide, retatrutide, SS-31, PT-141, tesamorelin, and BIMORELIN. FDA concluded that these products were unapproved new drugs based on its review of the company’s July 2026 website content.
TXP Innovations, doing business as Tex Peptides, received an August 24 letter concerning semaglutide, tirzepatide, retatrutide, SS-31, tesamorelin, PT-141, and Bacteriostatic Water. FDA’s review of the company’s website occurred in July 2026.
Peak Performance Peptides received a similar letter covering Bac water, retatrutide, semaglutide, SS-31, PT-141, and tesamorelin.
The scientific literature demonstrates that some compounds cited in these letters have been extensively investigated, but that scientific evidence is distinct from the regulatory status of a product sold by a particular company. For example, Wilding et al. (2021) demonstrated substantial weight loss with once-weekly semaglutide in a randomized clinical trial of adults with overweight or obesity. Similarly, Kingsberg et al. (2019) reported phase 3 trial findings for bremelanotide in women with hypoactive sexual desire disorder.
Across the 14 FDA warning-letter cases involving peptide-related products discussed in this article, one of the most consistent issues is intended use. FDA’s 2026 warning letters show that website information can provide evidence of intended use, while facility inspections and manufacturing findings can also lead to regulatory action. Research-use language therefore did not automatically resolve the agency’s concerns when other website content indicated human use.
The letters also demonstrate FDA’s attention to injectable peptide products and products used to prepare them for injection. Several companies sold bacteriostatic water or reconstitution solutions alongside peptides that FDA considered injectable drugs. In the Peptide Partners and NuScience letters, FDA expressly treated these accompanying solutions as drugs based on how they were marketed and sold with the peptide products.
The FDA warning letters discussed in this article involve 14 companies and peptide-related or GLP-1-marketed products in 2026, including Gram Peptides, Prime Sciences, PekCura Labs, Lovega LLC dba Pink Pony Peptides, Mile High Compounds LLC, FormPour, Guangzhou Huli Technology Co., Ltd. dba Fantasy Face, GenoGenix LLC, Wholesale Peptide, Peptide Partners LLC, NuScience Peptides LLC, Royal Peptides LLC, TXP Innovations LLC dba Tex Peptides, and Peak Performance Peptides.
For companies operating in the research-peptide market, the 2026 warning letters provide concrete examples of the types of marketing practices that can attract FDA scrutiny. A research-use disclaimer is therefore only one part of the product presentation; the claims made throughout a company’s website and the way related injectable products are marketed can also become relevant to FDA’s regulatory analysis.
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