Your Website Copy Is the Evidence: How FDA Decides a Peptide Is a Drug (21 CFR 201.128 and 21 U.S.C. 321, 2026)

Two peptide letters dated August 24, 2026 say "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-014, REG-025, OPS-004, OPS-006). The test comes from 21 CFR 201.128: intent may be shown by expressions, design or composition, or circumstances surrounding distribution (REG-003). Source: FDA.

Updated October 28, 2026.

What is the short answer in one table?

Under 21 CFR 201.128 the intent that matters is "the objective intent of the persons legally responsible for the labeling of an article (or their representatives)" (REG-172). That intent "may be shown by such persons' expressions, the design or composition of the article, or by the circumstances surrounding the distribution of the article" (REG-003). FDA's NuScience and Peptide Partners letters each say "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-014, REG-025). In plainer words, the regulation names how intent may be shown, and the NuScience and Peptide Partners letters say evidence from the seller's website establishes it (REG-003, REG-014, REG-025). Check each row of the table below against the source it cites before you rely on it (REG-003, REG-014).

What does 21 U.S.C. 321 say makes something a drug?

Cornell's copy of 21 U.S.C. 321 lists "articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals" (REG-001). It also lists articles (other than food) intended to affect the structure or any function of the body of man or other animals (REG-001). In plainer words, each test describes an article by the use it is intended for (REG-001). Read the statute text for the wording of each test (REG-001).

The same section adds two further categories of article to the drug definition (REG-145, REG-146). It lists articles recognized in the official United States Pharmacopoeia, official Homoeopathic Pharmacopoeia of the United States, or official National Formulary (REG-145). It also lists articles intended for use as a component of any article specified in those clauses (REG-146). Read the statute text itself for these two categories (REG-145, REG-146).

What does 21 CFR 201.128 say "intended use" means?

21 CFR 201.128 says "intended uses or words of similar import" in the listed sections "refer to the objective intent of the persons legally responsible for the labeling of an article (or their representatives)" (REG-172). It lists sections 201.5, 201.115, 201.117, 201.119, 201.120, 201.122 and 1100.5 as places where those words appear (REG-172). In plainer words, in those sections "intended uses" means the objective intent of the persons legally responsible for the labeling, or their representatives (REG-172). Identify who is responsible for the labeling of your own products and pages (REG-172).

The eCFR text states that intent may be shown by such persons' expressions, the design or composition of the article, or by the circumstances surrounding the distribution of the article (REG-002). It adds that objective intent may, for example, be shown by labeling claims, advertising matter, or oral or written statements by such persons or their representatives (REG-002). In plainer words, the examples are things the responsible persons say, advertise or put in labeling (REG-002). Compare your own statements, product design, distribution and advertising against these lists (REG-002).

21 CFR 201.128: three ways objective intent may be shown

Who is legally responsible, and what do "label" and "labeling" cover?

21 CFR 201.128 says "intended uses" refer to the objective intent of the persons legally responsible for the labeling of an article (or their representatives) (REG-172), and 21 U.S.C. 321 defines "person" to include individual, partnership, corporation, and association (REG-160). The NuScience Peptides and Peptide Partners letters refer to "your" labeling and website (REG-006, REG-014, REG-025). The captured sources do not say who FDA treats as legally responsible in any particular seller structure. Check who in your business is responsible for the labeling and the website (REG-172).

The statute defines a label as a display of written, printed, or graphic matter upon the immediate container of any article (REG-154), and labeling as all labels and other written, printed, or graphic matter (1) upon any article or any of its containers or wrappers, or (2) accompanying such article (REG-155). FDA's NuScience letter offers "Examples from your product labeling, including on your website, that provide evidence of the intended use (as defined in 21 CFR 201.128)" (REG-006). The captured sources do not explain how FDA connects a web page to the statutory word "accompanying". Read that NuScience wording and the two definitions side by side when you review your own pages (REG-006, REG-155).

How does each phrase map to what FDA did in 2026? (centerpiece table)

FDA's NuScience and Peptide Partners letters each say the products "are drugs under section 201(g)(1) of the FD&C Act, 21 U.S.C. 321(g)(1)" (REG-182, REG-194). The statutory and regulatory phrases behind that wording come from 21 U.S.C. 321 and 21 CFR 201.128, and the examples come from the NuScience and Peptide Partners letters (REG-001, REG-003, REG-182). The captured sources hold no 2026 example for some of the phrases, and the table says so in those rows. Use the table as a lookup, and open the cited source before you rely on a row (REG-001, REG-182).

What website language did FDA quote in the NuScience letter?

FDA's NuScience letter offers "Examples from your product labeling, including on your website, that provide evidence of the intended use (as defined in 21 CFR 201.128)" (REG-006). One quoted passage describes a "novel investigational peptide being explored for its potential research applications" (REG-007), and another refers to "experimental research" (REG-012). In plainer words, FDA's letter presents examples from the product labeling, including the website, as evidence of intended use (REG-006). The captured sources do not say which passage FDA weighed most. Compare your own pages against these kinds of statements.

What website language did FDA quote in the Peptide Partners letter?

FDA's Peptide Partners letter quotes passages of text (REG-018, REG-019, REG-020, REG-021, REG-022, REG-023). peptideecommerce.com's own tool data dates the letter August 24, 2026 and records it as a website offering peptide products (OPS-006). The letter lists "Reconstitution Solution (BAC)" among its cited products (REG-017). This guide does not repeat the passages and makes no statement about what any compound does. Read the quoted passages in the FDA letter itself before you judge your own pages (REG-018, REG-023).

Does a "research use only" label change what FDA wrote?

FDA's NuScience letter quotes the seller's label wording "for laboratory, research, and analytical use" and "not intended for human or veterinary use," in a sentence that begins "Despite statements on your product labeling" (REG-015). In plainer words, the sentence names the label wording the seller used (REG-015). The same letter separately states that "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-014). Compare the research use wording on your own labels with the wording FDA quoted (REG-015).

FDA's Peptide Partners letter quotes the seller's label wording "for research use only" and "not for human or veterinary use," in a sentence that begins "Despite statements on your product labeling" (REG-026). Unlike the NuScience wording "for laboratory, research, and analytical use" (REG-015), this sentence names "for research use only" (REG-026). The same letter separately states that "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-025). Compare the label wording in both letters with your own labels (REG-015, REG-026).

What exactly did FDA say about website evidence?

Both letters state the same finding about the seller's website (REG-014, REG-025). The NuScience and Peptide Partners letters use the same words: "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-014, REG-025). In plainer words, FDA wrote that evidence from the website establishes what the products are intended to be (REG-014, REG-025). Review the text on your own website with this finding in mind (REG-014, REG-025).

FDA's NuScience letter describes its examples as ones "that provide evidence of the intended use (as defined in 21 CFR 201.128) of these products as drugs" (REG-006). In plainer words, the letter says its examples are evidence of intended use as 21 CFR 201.128 defines it (REG-006). Read 21 CFR 201.128 alongside the letter's wording (REG-006).

How did the March 2026 letters describe website offers?

Letters dated March 31, 2026 also describe website offers (OPS-010, OPS-011, OPS-012, OPS-013). peptideecommerce.com's own tool data lists Gram Peptides, Lovega LLC dba Pink Pony Peptides, Mile High Compounds LLC and Prime Sciences (OPS-010, OPS-011, OPS-012, OPS-013). The tool data records each as a website offering products cited by FDA as unapproved new drugs (OPS-010, OPS-011, OPS-012, OPS-013). Its evidence quote for the Mile High Compounds letter is "The FDA has observed that your website offers" followed by named products (OPS-109). The Mile High record also lists a linked community forum (OPS-012). In plainer words, the Mile High quote says FDA observed the offers on the firm's website (OPS-109).

What does "new drug" add, and what follows in the letters?

The new drug definition and the August letters both refer to what is generally recognized as safe and effective (REG-157, REG-183, REG-195). The statute defines a new drug in part as a drug whose composition is such that it is not generally recognized, among qualified experts, as safe and effective for use under the conditions prescribed, recommended, or suggested in the labeling (REG-157). Both letters say the products are new drugs under section 201(p) of the FD&C Act because they are not generally recognized as safe and effective (GRASE) (REG-183, REG-195). Unlike the statute's general definition (REG-157), the letters apply the term to the products they cite (REG-183, REG-195). Read section 201(p) in the statute text alongside the letters (REG-157, REG-183).

FDA's NuScience and Peptide Partners letters each state that no approved applications pursuant to section 505, 21 U.S.C. 355, are in effect for these products (REG-185, REG-197). They state that introduction into interstate commerce of these unapproved new drug products violates sections 301(d) and 505(a), 21 U.S.C. 331(d) and 355(a) (REG-186, REG-198). In plainer words, each letter says no approved application is in effect and cites sections 301(d) and 505(a) for introducing the products into interstate commerce (REG-185, REG-197, REG-186, REG-198). Check which sections a letter cites for each product it names (REG-186, REG-198).

FDA's NuScience letter warns: "Failure to adequately address violations may result in regulatory or legal action without further notice including, without limitation, seizure and injunction." (REG-016). The Peptide Partners letter holds the same sentence (REG-199). Both letters set a window of fifteen (15) business days of receipt for a response (REG-068, REG-071). In plainer words, each letter pairs the warning of regulatory or legal action with a fifteen business day response window (REG-016, REG-199, REG-068, REG-071). Note the response window in any FDA letter you receive, together with the warning (REG-016, REG-068).

What do the food, supplement, device and cosmetic definitions say?

The statute defines other categories alongside "drug" (REG-151, REG-152, REG-161). It defines a device as an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, with conditions about chemical action and metabolism (REG-151). It defines a dietary supplement as a product (other than tobacco) intended to supplement the diet that bears or contains one or more listed dietary ingredients (REG-161). It deems a dietary supplement a food, except for purposes of paragraph (g) and section 350f of the title (REG-162). It defines a cosmetic as articles intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance, plus their components, and it excludes soap (REG-152). The captured sources do not say whether any peptide product fits any of these definitions. Read the statute text before you place any product in a category (REG-151, REG-161).

Can intended use change after a product ships?

The regulation says intended uses can change after a product ships (REG-174). It states that the intended uses of an article may change after it has been introduced into interstate commerce by its manufacturer (REG-174). It also says a packer, distributor, or seller is required to supply adequate labeling in accordance with the new intended uses (REG-004). Check your labeling whenever the way you offer a product changes (REG-004).

21 CFR 201.128 says objective intent may be shown, for example, by circumstances in which the article is, "with the knowledge of such persons or their representatives, offered or used for a purpose for which it is neither labeled nor advertised" (REG-173). The same sentence adds a proviso: "a firm would not be regarded as intending an unapproved new use for an approved drug based solely on that firm's knowledge that such drug was being prescribed or used by health care providers for such use" (REG-173). In plainer words, the proviso covers a firm that merely knows health care providers use an approved drug for that use (REG-173). Compare the uses your pages describe with the uses your labeling states (REG-173).

What can this guide not tell you?

The captured sources do not say how FDA weighs one kind of evidence against another. They do not say whether a website without any quoted claim would be treated the same way as the sites in these letters. They hold no 2026 example for the "design or composition" phrase. Ask a licensed attorney how these gaps apply to your pages.

An FDA warning letter supports only the statement that FDA cited a seller for something. It does not support a statement that a compound is illegal. For your own site, talk to a licensed attorney for your situation.

FAQ

What did FDA say about websites in August 2026?

Two letters dated August 24, 2026 each say "evidence obtained from your website establishes that your products are intended to be drugs for human use" (REG-014, REG-025). Sources: FDA NuScience letter, FDA Peptide Partners letter.

Which regulation do the letters point to?

The NuScience letter refers to intended use "as defined in 21 CFR 201.128" (REG-006).

What kinds of evidence does 21 CFR 201.128 list?

It lists expressions, design or composition of the article, and circumstances surrounding distribution, and gives labeling claims, advertising matter, and oral or written statements as examples (REG-003, REG-002).

Did "research use only" wording appear in the letters?

Yes. FDA wrote "Despite statements on your product labeling" with research use or laboratory use and not for human or veterinary use wording (REG-015, REG-026).

Whose intent does the regulation refer to?

The objective intent of the persons legally responsible for the labeling of an article, or their representatives (REG-172).

What does the statute say about interstate commerce?

It defines interstate commerce as commerce between any State or Territory and any place outside thereof, and commerce within the District of Columbia or within any other Territory not organized with a legislative body (REG-159).

How long did the letters give for a response?

Within fifteen (15) business days of receipt (REG-068, REG-071).

Is this legal advice?

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

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