Every FDA Warning Letter to a Peptide Seller in 2025 and 2026: 11 Letters, Dates and What FDA Cited

peptideecommerce.com's FDA warning letters tool lists 11 letters to peptide sellers dated 2025-12-08 to 2026-08-24: 1 in 2025 and 10 in 2026. Five carry the date 2026-08-24, four 2026-03-31, one 2026-06-17 and one 2025-12-08. Two, to NuScience Peptides and Peptide Partners, were read in full. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014)

Updated October 28, 2026.

Which 11 sellers received the letters?

Eleven sellers appear on peptideecommerce.com's FDA warning letters list, with a letter date for each. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) The list comes from peptideecommerce.com's own tool data, not from a separate FDA index. (OPS-099, OPS-100) The table gives each recipient as the tool records it, the letter date, and the ID at the end of the FDA URL. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) Use the table to find a seller's letter date, then open the FDA page for that letter.

Where does this letter list come from?

The letter list comes from a search of FDA's published warning letters filtered by search queries. (OPS-100) The tool data records its source as FDA warning letters on fda.gov, filtered by search queries that include "peptide", "research use only", "retatrutide", "BPC-157" and "tirzepatide research". (OPS-100) It lists the retrieved date 2026-10-07 for the letters. (OPS-099) The captured sources do not say whether FDA issued other peptide related letters outside those search queries.

When were the letters dated?

Letters per date: five on 2026-08-24, four on 2026-03-31

Where is each letter on fda.gov?

The tool data records an fda.gov address for each of the eleven letters. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) Each address begins with https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/ and ends in a slug that holds the recipient name, a number and the date. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) The table gives the slug for each recipient, so the full address is the prefix plus the slug. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) Open the FDA page for any letter you rely on and read it, rather than relying on the tool's summary.

What did FDA cite each seller for?

Ten of the tool's summaries describe a website, or a website and a linked community forum, offering products that FDA cited as unapproved new drugs. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013) The eleventh, Darmerica, is described as distribution of peptide active pharmaceutical ingredients to compounders. (OPS-014) In plainer words, the tool attaches a one line summary of the practice cited to each letter, and the table below reproduces those summaries. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) These are the tool's summaries, not the full text of the letters. Read the full FDA letter for any seller you want to compare yourself against.

Which product names appear in FDA's quoted evidence?

The tool data records an evidence quote for each letter, and the quotes list product names the sellers used. (OPS-101, OPS-102, OPS-103, OPS-104, OPS-105, OPS-106, OPS-107, OPS-108, OPS-109, OPS-110, OPS-111) The table shows the product names inside each quote, with water products noted generically. (OPS-101, OPS-102, OPS-103, OPS-104, OPS-105, OPS-106, OPS-107, OPS-108, OPS-109, OPS-110, OPS-111) Unlike the shorthand labels GLP-1 SM, GLP-2 TRZ and GLP-3 RT in the Mile High Compounds record (OPS-109), the Royal Peptides record lists names such as Tirzepatide and Semaglutide (OPS-104). Compare the product names on your own pages with the names in the table.

Water products appear in five of the evidence quotes recorded in the tool data, those for Peak Performance, Gram, Pink Pony, Mile High and Prime Sciences. (OPS-102, OPS-107, OPS-108, OPS-109, OPS-110) FDA's NuScience letter states that Bacteriostatic water for Peptides (BAC Water) is an unapproved new drug under section 505(a), and FDA's Peptide Partners letter states the same under section 505(a) of Reconstitution Solution (BAC). (REG-005, REG-017) In plainer words, a water or reconstitution product is named in those quotes and in both full letters. (OPS-102, OPS-107, OPS-108, OPS-109, OPS-110, REG-005, REG-017) Check whether your own listings name a water product together with peptide names.

What do the two letters read in full give as issuing office and reference number?

The letters to NuScience and Peptide Partners share an issuing office, and each carries a reference number. (REG-181, REG-193, REG-180, REG-192) Each letter states the issuing office as the Center for Drug Evaluation and Research (CDER). (REG-181, REG-193) The NuScience letter carries reference number 733652 and the Peptide Partners letter carries 735063. (REG-180, REG-192) In plainer words, both letters come from the same FDA center and each has its own number. (REG-181, REG-193, REG-180, REG-192) Both letters therefore name CDER as the issuing office and give a reference number.

Both letters tell the recipient to put the reference number in the email subject line of its response. (REG-178, REG-190) The NuScience letter says to identify the response with reference number 733652 in the subject line, and the Peptide Partners letter says the same for 735063. (REG-178, REG-190) In both letters the reference number goes in the subject line of the email that carries the response. (REG-178, REG-190)

For the other nine letters, the site's tool data records an FDA URL that ends in a number and a date. (OPS-005, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) The Gram Peptides record, for example, gives a URL ending "gram-peptides-721806-03312026". (OPS-010) The captured sources do not give an issuing office for these nine letters. Read each letter on FDA's site for its issuing office.

Which products does FDA say are unapproved new drugs in the two full letters?

FDA's NuScience letter states that GLP-2 Tirz Peptide, GLP-1 Sema Research Peptide, GLP-3 RT (Retatrutide) Research Peptide, Survodutide, Mazdutide, PT-141 Peptide (Bremelanotide), Tesamorelin Research Peptide, Tesamorelin Ipamorelin Blend, and Bacteriostatic water for Peptides (BAC Water) are unapproved new drugs under section 505(a). (REG-005) In plainer words, the letter names these items as unapproved new drugs under section 505(a), the water product among them. (REG-005) Compare the product names on your own pages with the names in this list.

FDA's Peptide Partners letter states that GLP-1 S (Semaglutide), GLP-2 T (Tirzepatide), GLP-3 Reta (Retatrutide), SS-31 (Elamipretide), Tesa Peptide (Tesamorelin), PT-141 (Bremelanotide), and Reconstitution Solution (BAC) are unapproved new drugs under section 505(a). (REG-017) Unlike the NuScience list (REG-005), the Peptide Partners list names SS-31 (Elamipretide). (REG-017) Compare the product names on your own pages with the names in this list.

What statute sections do the full letters cite?

The NuScience letter cites section 201(p), section 505(a), section 505 and sections 301(d) and 505(a), and the Peptide Partners letter carries the same statements in the same wording. (REG-183, REG-184, REG-185, REG-186, REG-195, REG-196, REG-197, REG-198) In plainer words, the table below, which gives the NuScience wording, applies to both letters. (REG-183, REG-184, REG-185, REG-186, REG-195, REG-196, REG-197, REG-198) Check each provision in the table against the letter you read.

FDA's NuScience letter states that its products are drugs under section 201(g)(1) of the FD&C Act, 21 U.S.C. 321(g)(1), and the Peptide Partners letter uses the same wording. (REG-182, REG-194) In plainer words, both letters name section 201(g)(1) as the provision under which they call the products drugs. (REG-182, REG-194) Check section 201(g)(1) in the letter you read before comparing it with your own product claims.

FDA's NuScience letter says the products "are drugs under section 201(g)(1) of the FD&C Act, 21 U.S.C. 321(g)(1), because they are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, and/or intended to affect the structure or any function of the body." (REG-182) Source: NuScience Peptides LLC warning letter. In plain words, the reason FDA gives is the use the products are intended for. (REG-182) Read the full sentence in the letter, including the "and/or" wording, before comparing it with your own product claims.

How does FDA tie a website to intended use?

FDA's NuScience letter lists examples from the product labeling, including on the website, as evidence of intended use. (REG-006) The letter words it as: "Examples from your product labeling, including on your website, that provide evidence of the intended use (as defined in 21 CFR 201.128) of these products as drugs". (REG-006) In plain words, the examples come from the product labeling, and that includes the website. (REG-006) Compare the claims on your own website with the claims on your product labeling.

The rule FDA cites says intent can be shown in several ways. (REG-003, REG-002) 21 CFR 201.128 says that intent may be shown by a person's expressions, the design or composition of the article, or by the circumstances surrounding its distribution. (REG-003) It also says that objective intent may be shown by labeling claims, advertising matter, or oral or written statements by such persons or their representatives. (REG-002) In plain words, the rule names expressions, the design or composition of the article, the circumstances of distribution, labeling claims, advertising matter and statements. (REG-003, REG-002)

FDA's NuScience and Peptide Partners letters each say the sale of products together demonstrates the intended use of a named solution sold with them. (REG-013, REG-024) The NuScience letter names "Bacteriostatic water for Peptides (BAC Water)" and the Peptide Partners letter names "Reconstitution Solution (BAC)", each followed by "to be used in combination for injection" (sources: NuScience letter, Peptide Partners letter). (REG-013, REG-024) In plainer words, FDA treats how products are sold together as evidence of how that solution was meant to be used. (REG-013, REG-024) Check how your own listings group a solution with other products.

What does FDA ask the recipient to do?

Both letters ask for a response within fifteen (15) business days of receipt. (REG-068, REG-071) Both ask for the written response to be sent to [email protected]. (REG-069, REG-072) Both also ask for the specific steps taken to correct violations, an explanation of each step taken against recurrence, and copies of related documentation. (REG-070, REG-073) In plainer words, the letters give a deadline, an address and what the response must contain. (REG-068, REG-069, REG-070, REG-071, REG-072, REG-073) Compare the response instructions in any letter you read with the rows of the table.

What the two letters read in full ask of the recipient

What can happen if the violations are not addressed?

The NuScience letter warns that regulatory or legal action may follow without further notice if the violations are not adequately addressed. (REG-016) The letter names seizure and injunction as examples. (REG-016) The Peptide Partners letter uses the same sentence. (REG-199) Both letters state that regulatory or legal action may follow, with seizure and injunction named. (REG-016, REG-199)

FDA's NuScience letter says failure to adequately address violations may result in regulatory or legal action without further notice. (REG-016) FDA's words: "Failure to adequately address violations may result in regulatory or legal action without further notice including, without limitation, seizure and injunction." (REG-016) Source: NuScience Peptides LLC warning letter. In plain words, the letter names seizure and injunction as examples of that action, and the list is not limited to them. (REG-016) Read the full sentence in the letter before relying on this summary.

How is the Darmerica letter different?

The tool data describes the Darmerica letter dated 2025-12-08 as concerning distribution of peptide active pharmaceutical ingredients to compounders, cited for violations of the FD&C Act. (OPS-014) It also records the evidence quote that GLP-1 APIs were shipped to the firm as "custom peptide," omitting the drug name, since March 2022. (OPS-111) In plain words, the quote describes how the ingredients were named when shipped to the firm. (OPS-111) Unlike the website offerings described in the summaries for the other sellers, the Darmerica summary describes distribution to compounders. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) Check whether your own activity is a website offering or distribution to compounders before comparing it with these entries.

What does a warning letter support, and what does it not?

FDA's NuScience and Peptide Partners letters state that the items they name are unapproved new drugs under section 505(a). (REG-005, REG-017) The NuScience letter states this of its named items, and the Peptide Partners letter states the same about its named items. (REG-005, REG-017) In plainer words, the conclusion in each letter is about the items that letter names. (REG-005, REG-017) The captured sources do not say that these conclusions extend to any compound outside those letters. Check which items a letter names before applying its conclusion to another product.

Nine of the letters are known here through the tool's summaries and evidence quotes. (OPS-005, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) They are Peak Performance Peptides, Royal Peptides, Tex Peptides, Wholesale Peptide, Gram Peptides, Pink Pony Peptides, Mile High Compounds, Prime Sciences and Darmerica. (OPS-005, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) The tool data records a summary and an evidence quote for each of them. (OPS-005, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014) The captured sources do not give the full letter text for these letters, and do not say what they state about a response deadline, an issuing office or statute sections.

FAQ

How many FDA warning letters to peptide sellers are on peptideecommerce.com's list?

The tool lists 11, with dates from 2025-12-08 to 2026-08-24. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008, OPS-009, OPS-010, OPS-011, OPS-012, OPS-013, OPS-014)

Which letters are dated 2026-08-24?

NuScience Peptides LLC, Peak Performance Peptides, Peptide Partners LLC, Royal Peptides LLC and TXP Innovations LLC dba Tex Peptides. (OPS-004, OPS-005, OPS-006, OPS-007, OPS-008)

How long does the recipient have to respond?

The NuScience and Peptide Partners letters ask for a written response within fifteen (15) business days of receipt. (REG-068, REG-071)

Which FDA office issued the letters read in full?

The Center for Drug Evaluation and Research (CDER) is the issuing office in both. (REG-181, REG-193)

What reference numbers do the full letters carry?

The NuScience letter carries 733652 and the Peptide Partners letter carries 735063. (REG-180, REG-192)

Did any letter involve a seller that did not run a website store?

The tool data describes the Darmerica, LLC letter as concerning distribution of peptide active pharmaceutical ingredients to compounders. (OPS-014)

Does a letter say a compound is illegal?

The captured sources do not say that a letter makes a statement about any compound in general. The NuScience letter states conclusions about its listed products, naming them as unapproved new drugs. (REG-005)

Is this legal advice?

No. This guide reports what the sources say. Talk to a licensed attorney for your situation.

Sources