Regulatory Warning Letters and Alerts

How to read these documents

• A warning letter says FDA believes a firm has violated the law and asks for correction. It is not a court finding.
• A list entry (for example in FDA's compounding bulk-substance categories) records a regulatory position on one substance for one purpose, not a verdict on every use.
• An alert is a public message about risk.

FDA warning letters about "research" peptide sellers (United States)

Several letters read this session (dated 2024 to 2025) share a pattern:

• FDA concluded that products labeled "research use only" or "research chemical only" were intended as drugs for human use, based on evidence from the sellers' websites. [1][2]
• One February 2025 letter said the products were prescription drugs for conditions not amenable to self-diagnosis, so adequate directions for lay use could not be written. [3]
• The same letter noted that products intended for injection heighten the public health concern. [3]
• A September 2025 letter about a compounded-drug website said retatrutide products were not eligible for compounding exemptions because retatrutide is not in a USP or NF monograph, not part of an FDA-approved human drug and not on the 503A bulks list. [4]

FDA's GLP-1 page (current as of 10/01/2026) says retatrutide and cagrilintide cannot be used in compounding under federal law and that FDA has warned telehealth companies, ingredient distributors and outsourcing facilities. [5] It also says that, as of May 31, 2026, FDA had received 990 reports of adverse events associated with compounded semaglutide, and that it is not always possible to tell whether the drug caused each event. [5]

FDA compounding lists: what the pages say (United States)

FDA's page on bulk substances that may present significant safety risks (current as of 04/22/2026) has two tables. [6]

The page says the withdrawn table lists substances previously in category 2 that were withdrawn by the nominators. [6] Its entry for BPC-157 still describes immunogenicity risk and limited safety information. [6] FDA's 503A page says substances in categories 2 or 3 can draw enforcement under general policies, and that FDA does not intend to place substances nominated on or after January 7, 2025 into these categories. [7] I could not read FDA's Category 1 list this session, so I cannot say whether BPC-157 or any other peptide is on it. That is not verified.

An FDA advisory committee met on July 23-24, 2026 on BPC-157 and other substances. [8] FDA's briefing concluded that a balancing of criteria weighs against placing BPC-157 on the 503A bulks list. [8] News reports say the committee voted to recommend adding BPC-157, KPV, TB-500, MOTS-c, epitalon and semax to the list, and that the vote is non-binding and needs FDA sign-off. [9] I did not find an FDA page recording the outcome, so treat the vote as reported, not confirmed. Rules and lists change, so check the FDA pages linked in the sources.

United Kingdom

The MHRA said in December 2025 that products sold illegally may be fake, contaminated, incorrectly dosed or contain unlisted powerful ingredients, and asked the public to report suspicious products through the Yellow Card scheme. [10]

Other regulators

Proper evidence not found here for Australia (TGA), Canada or the EU: the TGA and Health Canada sites could not be read this session, and the EU was not checked.

What to do with an alert

If you have a product-related reaction, see Reporting Adverse Events for Peptide Products. For context on specific compounds, see BPC-157: What Research Shows and What It Does Not, Compounded and Unapproved GLP-1 Products and Peptide Safety.