FDA peptide warning letters: 18 verified research-seller records

By Peptide Care Index · Updated October 2026

This register contains 18 FDA peptide warning letters to online suppliers using research-only disclaimers, issued in 2024–2026. In 9 of its 11 letters issued in 2026, FDA also identified water or reconstitution products as unapproved drugs, according to Peptide Care Index’s October 2026 analysis. Each record links to the original FDA letter.

Key FDA peptide warning-letter statistics

• 18 verified letters: Peptide Care Index’s register contains 18 FDA letters to online suppliers using research-only or similar disclaimers, checked October 14, 2026. Their issue dates run from February 7, 2024, to August 24, 2026. See the source-linked register.Copy statistic, source and link
• 9 of 11 letters issued in 2026 (81.8%): In this register, FDA separately identifies water or reconstitution products as unapproved drugs in 9 of the 11 letters with 2026 issue dates. This is Peptide Care Index’s analysis of the nine FDA records.Copy statistic, source and link
• 13 of 18 letters: Retatrutide is explicitly named or expressly identified behind a product code in 13 letters in this register. Unexpanded codes are excluded from that count. FDA record matrix, checked October 14, 2026.Copy statistic, source and link
• 5 letters dated August 24, 2026: The latest issue-date group in this register names NuScience Peptides, Royal Peptides, Peptide Partners, Tex Peptides and Peak Performance Peptides. FDA posted those records on September 1, 2026. Register and sources.Copy statistic, source and link
• 5 core letters dated March 31, 2026, posted April 7: The register separates these research-label supplier letters from two same-date eBay consumer-product letters. Related records and sources.Copy statistic, source and link
• BPC-157 was named in a 2020 letter: The October 23, 2020 FDA/FTC letter to Predator Nutrition includes Unbreakable, labelled as containing BPC-157. It sits outside this register’s 2024–2026 period. FDA letter.Copy statistic, source and link

Which FDA peptide warning letters are in the register?

The register contains 18 letters to online suppliers whose peptide marketing FDA reviewed despite research-only or similar disclaimers. It covers letters issued from 2024 through the October 14, 2026 check; the newest included issue date is August 24, 2026. These are verified records under a stated scope, not a count of all FDA enforcement involving peptides.

Source: Each linked FDA letter was read directly and checked on October 14, 2026. Posting dates come from the FDA warning-letter database. Dates use YYYY-MM-DD. The last column is the FDA’s MARCS-CMS record identifier.

Product labels are retained from the formal drug findings. Water is included when FDA separately identifies it there. The domains are those cited in the letters, not a check of who operates them today. A label in this table is not a laboratory test of what a product contains. Download the complete letter register (CSV).

Why do 9 of the 11 letters issued in 2026 also name water products?

In 9 of the 11 letters issued in 2026 in this register, FDA identifies a water or reconstitution product as an unapproved drug alongside peptide products. The share is 81.8%: 9 ÷ 11 × 100, rounded to one decimal place. It measures the contents of these letters, not the share of all sellers that offer water.

Source: Peptide Care Index’s coding of the 11 FDA letters issued in 2026 in the register above, checked October 14, 2026. The two without a separate finding are Wholesale Peptide and Royal Peptides.

Source: The formal unapproved-drug findings in each linked FDA letter, checked October 14, 2026.

The Gram Peptides letter explains the connection: the company sold water alongside peptide products intended for injection and requiring reconstitution. FDA treated that pairing as evidence of intended injection use. The point was how the products were marketed together.

There is a useful distinction here. 11 of the 18 letters mention water as intended-use or injection-risk evidence, but 9 of the 18 separately identify a water product as unapproved. The USApeptide letter discusses water and syringes without a separate water-product finding. Royal’s letter cites water in a footnote but names peptide products in its formal findings. The two fields stay separate in the download.

Which peptide names appear in the letters?

Among the 18 records, semaglutide appears in 14 formal-product records, retatrutide in 13 and tirzepatide in 11. These counts use explicit names or identities established in the FDA letter. They do not guess the meaning of an unexpanded product code or count a molecule merely mentioned in unrelated quoted advertising.

Source: Peptide Care Index’s classification of the linked FDA letters, checked October 14, 2026. One letter can appear in several rows; these counts must not be added to estimate the number of letters. A named blend contributes once to each expressly identified component. Water is excluded from this peptide-name table. PT-141 aliases are grouped under PT-141; source-specific labels remain in the CSV.

Why are some product codes left unexpanded?

The PekCura letter lists GLP-1-S, GLP-2-T and GLP-3-R without spelling out the molecules behind those codes. The NuScience letter lists GLP-2 Tirz Peptide without expressly expanding it to tirzepatide. Those labels remain separate in this source-based count.

PekCura’s letter also discusses a Cag/Tirz blend in its intended-use examples, including a reference to cagrilintide. That additional example is retained in the product download, outside the count based on its formal introductory product list. Similarly, tirzepatide appears in quoted marketing in Prime Peptides’ letter, whose formal findings name semaglutide and retatrutide. Keeping those layers separate makes the count reproducible.

Download the product labels and additional evidence records (CSV).

Why do other FDA peptide warning-letter lists show different totals?

A list of peptide suppliers, a list of letters that mention retatrutide, and a list of all GLP-1 advertising warnings count different things. This register counts 18 research-label peptide-supplier letters. It separates consumer-product letters, letters about other drugs, manufacturing cases, and older records.

Source: The linked FDA letters, checked October 14, 2026. Separate means outside this register’s definition, not unimportant or compliant.

That explains two common counting traps. First, Pinnacle’s December 12, 2025 letter concerns S4/andarine, LGD-4033 and MK-2866. Its company name includes Peptides, but the products in that letter are SARMs—selective androgen receptor modulators—not peptide products. Second, the March 31, 2026 letters to FormPour and Fantasy Face concern eBay consumer products rather than the research-label supplier category used here.

Atomix’s December 12, 2025 letter also names SARMs. PureRawz’s September 8, 2025 letter names tianeptine products. Neither enters the peptide-product count just because the seller uses research language or may be associated with peptides elsewhere.

On March 3, 2026, FDA separately announced warning letters to 30 telehealth companies over illegal marketing of compounded GLP-1 products. That is a different group. It is not an extra 30 research-peptide suppliers in this register.

Ingredient-list decisions answer another question. The FDA peptide compounding list tracks those records separately from letters to sellers.

Are these March warning letters or April warning letters?

The five March 31, 2026 research-supplier letters in this register were posted by FDA on April 7, 2026. Both dates are real, but they measure different events. The letter date is when the letter was issued; the posted date is when FDA made the record public in its index.

Source: Linked FDA letters and the FDA warning-letter index, checked October 14, 2026. Counts are records in this register, not all FDA letters issued on these dates.

What does an FDA warning letter actually mean?

A warning letter states FDA’s findings and gives the recipient an opportunity to address them. It is an advisory action, not itself a court judgment. It also does not, by itself, establish a recall, a company closure, or a ban on every peptide. FDA Regulatory Procedures Manual, Chapter 4.

In the US Chem Labs letter, FDA relied on the seller’s website claims despite research-only wording. In the Swisschems letter, the agency also considered linked social-media marketing. The practical lesson is specific: FDA’s intended-use analysis considered the surrounding claims, not the disclaimer alone.

Source: About Warning and Close-Out Letters, FDA’s warning-letter index and Regulatory Procedures Manual, Chapter 4. The last two limits follow from the register’s scope and FDA’s warning that later interactions can change the status of issues in a letter.

Many letters here request a written response within 15 working or business days. That is the response deadline stated in the letter, not a 15-day permission to keep selling. For example, see Swisschems and Wholesale Peptide. Other enforcement letters can set different deadlines: the 2020 Predator Nutrition letter requested a response within 48 hours.

Has FDA issued a warning letter that names BPC-157?

Yes. The October 23, 2020 FDA/FTC letter to Predator Nutrition names Unbreakable, labelled as containing BPC-157, among products marketed with COVID-19 claims. That historical record is outside this register’s 2024–2026 period. Read the FDA letter.

BPC-157 is not named in the formal-product list of these 18 core records. That narrow finding does not erase the older letter or establish BPC-157 approval. For the separate approval question, see BPC-157 FDA approval status; for the different access routes, see how BPC-157 access works.

Do these letters mean FDA banned all peptides?

No. These 18 records concern the named suppliers and products under this register’s scope. FDA’s current unapproved-GLP-1 guidance separately addresses products falsely sold to consumers as research products and states that retatrutide and cagrilintide cannot be used in compounding under federal law. FDA’s concerns with unapproved GLP-1 drugs, checked October 14, 2026.

Do not turn a supplier’s unapproved semaglutide product into a claim that no semaglutide medicine is approved. The USApeptide letter expressly distinguishes its products from FDA-approved versions. The same distinction matters when reading supplier claims about a trial, an ingredient, or an approved brand.

A warning letter, a compounding-list change, and an advisory meeting are separate records. The FDA peptide hearing reference covers meeting notices; this page covers seller letters.

How did we build the FDA Peptide Letter Register?

Peptide Care Index collected and read 18 full FDA letters, checked on October 14, 2026. We used FDA’s warning-letter index, its downloadable search results, targeted recipient and peptide searches, and direct letter pages. We also read related records to check the boundaries of the count.

Inclusion rule. The core register includes a public FDA warning letter issued from January 1, 2024, through the October 14, 2026 check when it identifies peptide or peptide-labelled products offered by an online supplier and addresses research-only, not-for-human-use, or similar disclaimer language. The period is a collection boundary, not a claim that enforcement began in 2024.

Unit. One MARCS-CMS identifier is one letter. A company’s legal name, trading name, extra mailing address or second name in the same letter does not create another record.

Product coding. We preserve the products in the letter’s formal unapproved-drug findings. We record additional intended-use examples separately. We map a code to a molecule only when the FDA letter establishes that identity; unexpanded codes remain literal. A blend contributes once to each identified component in the compound table. Repeated appearances of the same molecule within one letter count once.

Water coding. “Separately identified” means FDA includes the water or reconstitution product in its formal unapproved-drug findings. A passing reference, injection-risk discussion or footnote alone does not qualify. “Cited as evidence” is a broader, separate field. Neither field is a lab result.

Date coding. The issue date comes from the letter. The posted date comes from FDA’s warning-letter index. Our check date records when we verified the source. None is interchangeable with a company’s launch, shutdown, or current compliance date.

Reproduce the result. Open the letter CSV, keep rows whose letter_date starts with 2026, and count distinct marcs_cms_id values: 11. Keep water_explicitly_unapproved_product = true: 9. Divide 9 by 11 and multiply by 100: 81.818…%, displayed as 81.8%. The IDs and FDA URLs in the summary download make the numerator and denominator traceable.

What this is. A dated primary-source compilation with original classification and arithmetic. It is not a seller survey, a product-testing study, or a legal opinion.

What can’t this register tell you?

The 18 records do not measure how many peptide sellers exist, how often violations occur, how many customers were harmed, or whether a company is operating now. This is a verified register under the inclusion rule above, not an exhaustive census of every FDA letter that mentions a peptide.

Search results can omit records, and new letters can be posted after this check. The related-record download documents selected boundary cases; it is not a list of every excluded FDA letter. We did not inspect every seller’s current website, test a product, or determine current compliance.

FDA cautions that later interactions with a recipient may change the status of issues discussed in a warning letter. Its close-out process also has limits. A missing close-out link is therefore not a reliable “still violating” label. FDA index; FDA close-out explanation.

If you are deciding between clinical care and a research-store purchase, Find My Peptide Path helps separate those routes and the questions each one raises.

How can you cite or download this analysis?

Publication: Peptide Care Index. Page: FDA peptide warning letters: 18 verified research-seller records. Edition checked: October 14, 2026. URL: https://peptidecareindex.com/research/fda-peptide-warning-letters/

Ready-to-copy citation: Peptide Care Index. “FDA peptide warning letters: 18 verified research-seller records.” October 14, 2026 edition. https://peptidecareindex.com/research/fda-peptide-warning-letters/

Ready-to-copy finding: “In 9 of the 11 letters issued in 2026 in Peptide Care Index’s research-label peptide-supplier register, FDA also identified water or reconstitution products as unapproved drugs.”

Use the water finding for that analysis, the full register for its scope, and the exact FDA letter for a statement about an individual firm. Keep the denominator and edition date when using a count.

The original compilation, classifications and charts are available under CC BY 4.0: credit Peptide Care Index by name, indicate changes and preserve FDA source attribution; this license does not relicense underlying third-party material.

Free downloads

• Letter register — 18 records (CSV)
• Formal product labels and additional intended-use evidence (CSV)
• Counts, denominators and contributing letter IDs (CSV)
• Selected related records and reasons they are outside the count (CSV)
• Water finding chart (SVG) · PNG
• Issue-date chart (SVG) · PNG

What else do readers ask about FDA peptide warning letters?

How many FDA peptide warning letters are there?

This page verifies 18 letters under its research-label online-supplier definition, checked October 14, 2026. It does not claim an all-time total for every peptide-related warning letter. Counts change when a list includes telehealth advertising, pharmacies, manufacturers, consumer products, older records, or SARMs-only letters.

What are the latest letters in this register?

The newest included issue date is August 24, 2026. The five recipients are NuScience Peptides LLC, Royal Peptides LLC, Peptide Partners LLC, TXP Innovations LLC dba Tex Peptides and Peak Performance Peptides. FDA posted them on September 1, 2026; newer or differently scoped records may exist outside this register.

Does “research use only” make a peptide product exempt?

The letters show FDA treating surrounding marketing as evidence of intended human drug use despite research-only disclaimers. Examples include website claims, linked social posts, guides, calculators and products sold together. A disclaimer alone does not settle the intended-use question in these records; read the particular letter for the evidence FDA relied on.

Did Gram Peptides receive an FDA warning letter?

Yes. FDA’s letter to Gram Peptides is dated March 31, 2026, record 721806, and names retatrutide, tirzepatide and Bacteriostatic Water for Injection. It was posted on April 7, 2026. Original FDA letter.

Does a warning letter prove that a company shut down?

No. A letter establishes FDA’s findings at the stated time, not a later closure. This register does not report current trading status. A closure, recall or lawsuit needs its own dated evidence.

Is a company without a warning letter FDA-approved?

No such conclusion follows. A missing record in this register is a statement about the dataset, not about approval or safety. Check the exact medicine’s approval record and the provider or pharmacy’s relevant licensing separately.

Which primary sources support this page?

All FDA letter sources below were read and checked on October 14, 2026. The register and product downloads retain the same source URLs and check date.

1. Synthetix Inc. DBA Helix Chemical Supply — 2024-02-07 — MARCS-CMS 668918. Checked 2026-10-14.
2. US Chem Labs — 2024-02-07 — MARCS-CMS 669074. Checked 2026-10-14.
3. Xcel Research LLC — 2024-12-10 — MARCS-CMS 694608. Checked 2026-10-14.
4. Prime Vitality, Inc. dba Prime Peptides — 2024-12-10 — MARCS-CMS 695156. Checked 2026-10-14.
5. Summit Research Peptides — 2024-12-10 — MARCS-CMS 695607. Checked 2026-10-14.
6. Swisschems — 2024-12-10 — MARCS-CMS 695663. Checked 2026-10-14.
7. USApeptide.com — 2025-02-26 — MARCS-CMS 696885. Checked 2026-10-14.
8. Lovega LLC dba Pink Pony Peptides — 2026-03-31 — MARCS-CMS 721088. Checked 2026-10-14.
9. Mile High Compounds LLC — 2026-03-31 — MARCS-CMS 721600. Checked 2026-10-14.
10. PekCura Labs — 2026-03-31 — MARCS-CMS 721709. Checked 2026-10-14.
11. Prime Sciences — 2026-03-31 — MARCS-CMS 721805. Checked 2026-10-14.
12. Gram Peptides — 2026-03-31 — MARCS-CMS 721806. Checked 2026-10-14.
13. Wholesale Peptide — 2026-06-17 — MARCS-CMS 729447. Checked 2026-10-14.
14. NuScience Peptides LLC — 2026-08-24 — MARCS-CMS 733652. Checked 2026-10-14.
15. Royal Peptides LLC — 2026-08-24 — MARCS-CMS 734884. Checked 2026-10-14.
16. Peptide Partners LLC — 2026-08-24 — MARCS-CMS 735063. Checked 2026-10-14.
17. TXP Innovations LLC dba Tex Peptides — 2026-08-24 — MARCS-CMS 735067. Checked 2026-10-14.
18. Peak Performance Peptides — 2026-08-24 — MARCS-CMS 735127. Checked 2026-10-14.
19. Pinnacle Professional Research dba Pinnacle Peptides — related record — 2025-12-12. Checked 2026-10-14.
20. FormPour — related record — 2026-03-31. Checked 2026-10-14.
21. Guangzhou Huli Technology Co., Ltd. dba Fantasy Face — related record — 2026-03-31. Checked 2026-10-14.
22. Atomix LLC — related record — 2025-12-12. Checked 2026-10-14.
23. PureRawz — related record — 2025-09-08. Checked 2026-10-14.
24. AnuMed International, LLC — related record — 2024-08-20. Checked 2026-10-14.
25. Supreme Rejuvenation, LLC — related record — 2025-05-05. Checked 2026-10-14.
26. Cholrem Pty Ltd dba Cholrem and Cholrem Pharmaceuticals — related record — 2024-07-09. Checked 2026-10-14.
27. Predator Nutrition — related record — 2020-10-23. Checked 2026-10-14.
28. FDA warning-letter index; posting dates and subsequent-interaction limitation. Checked 2026-10-14.
29. About Warning and Close-Out Letters. Checked 2026-10-14.
30. FDA Regulatory Procedures Manual, Chapter 4. Checked 2026-10-14.
31. FDA’s concerns with unapproved GLP-1 drugs used for weight loss. Checked 2026-10-14.
32. FDA warns 30 telehealth companies — March 3, 2026. Checked 2026-10-14.

Peptide Care Index Research is the research and reference section of peptidecareindex.com.