Federal regulators and state boards crack down on RUO peptides

In the past few weeks, the US Food and Drug Administration (FDA) issued warning letters to various online sellers of compounded peptides, including ipamorelin, tesamorelin, and glucagon-like peptide-1s (GLP-1s). The FDA warning letters did not reference any of the six peptides that FDA’s Pharmacy Compounding Advisory Committee recommended for inclusion on the 503A Bulk Drugs List. The stakes of noncompliance were underscored weeks earlier by a federal criminal case wherein a CEO faced a felony conviction and lengthy prison sentence for research-use-only (RUO) marketing of peptides, combined with outright fraud.

FDA warning letters to online peptide sellers

In August 2026, FDA issued warning letters to five online sellers – NuScience Peptides LLC, Royal Peptides LLC, Peptide Partners LLC, Peak Performance Peptides, and TXP Innovations LLC (d/b/a Tex Peptides) – for marketing unapproved and misbranded peptide products. The letters targeted tesamorelin and ipamorelin, signaling that FDA’s enforcement reach extends beyond the GLP-1 market to the broader sale of unapproved peptides for human use.

Even though the companies labelled their products “for research, laboratory, and analytical use” and “not for veterinary or human use,” FDA found that dosing information, injection instructions, and dose calculators posted on each company’s website established that the products were intended for human use. FDA also found that several companies’ “bacteriostatic water” offerings were themselves unapproved drugs, since they were intended for use in preparing an injection. The letters cited the products as unapproved new drugs and misbranded under the Federal Food, Drug, and Cosmetic Act, and warn that continued violations may result in seizure or injunction.

FDA’s Pharmacy Compounding Advisory Committee voted in July 2026 to recommend adding six peptides, including BPC-157, to the Section 503A Bulk Drugs List, a non-binding step that does not affect the RUO products at issue above. Whether FDA enforcement will extend to those six peptides remains unsettled; FDA’s recent actions illustrate a shifting enforcement landscape rather than a settled focus on any single peptide category. Sellers, compounders, and prescribers should keep abreast of new warning letters, agency positions, and state guidance and reassess their practices as enforcement targets and theories evolve.

States are also increasing their scrutiny of RUO peptides, reflecting a broader focus on product quality, prescriber responsibility, and patient safety.

For example, in a June 2026 notice, the Alabama Medical Board emphasized that physicians must obtain prescription products, drugs, and ingredients from entities permitted by the Alabama State Board of Pharmacy. The notice further states that:

All drugs administered or dispensed to a patient must be prescription quality; therefore, under no circumstances is it permissible for a physician to compound, administer, or dispense a non-FDA approved or research grade peptide to a patient. A physician may not circumvent his or her duty of care to patients by permitting or delegating the purchase, administration, or dispensing of these drugs to Certified Nurse Midwives (CNMs), Certified Registered Nurse Practitioners (CRNPs) or Physician Assistants (PAs). This prohibition includes advising, recommending, supplying, prescribing, or administering.

The Alabama guidance underscores the Board’s position that prescribers are responsible for ensuring that products used in patient care meet applicable “prescription quality” standards.

Ohio reinforced this position in December 2025 Board of Pharmacy guidance, advising that medications labeled “for research purposes only,” or with similar language, are unlawful for prescriber clinics and medical spas to possess, regardless of patient consent. The guidance encourages providers to dispose of RUO products and advise patients to discontinue their use.

These federal and state actions illustrate increasing scrutiny of RUO peptides and reinforce that regulators may look beyond the act of prescribing itself to evaluate product sourcing, compounding, ordering, possession, administration, and distribution.

United States v. Kawa: When RUO marketing becomes a federal crime

A July 2026 sentencing illustrates how RUO marketing and distribution can become a felony. Judge Cristal C. Brisco of the US District Court for the Northern District of Indiana sentenced Matthew Kawa, owner of Paradigm Peptides, to 70 months in federal prison for introducing unapproved drugs into interstate commerce with intent to defraud or mislead. Paradigm had about 54,000 unique customers across all 50 states and 80 countries, and Kawa agreed to forfeit $5 million in proceeds. The scale of the customer base and the forfeiture underscore that RUO marketing can create nationwide and international exposure when products are in fact sold for human consumption.

Paradigm marketed its products as RUO, despite knowing the products were intended for human use, and forged certificates of analysis to falsely vouch for the products’ quality. Government testing found that six compounds designed to mimic testosterone actually contained the steroid. Kawa admitted in his guilty plea that he “knew that Paradigm’s products were being marketed and sold for human consumption.” The US Department of Justice also noted that Kawa had ignored FDA warning letters sent in 2020 and 2022 for the same conduct, and that his repeated disregard of those warnings served as evidence of willfulness that likely factored into the decision to prosecute criminally. The combination of intended-use evidence, falsified quality documentation, and repeated disregard of FDA warnings illustrates how conduct initially addressed through civil enforcement can ultimately support criminal charges when sellers continue to operate.

The case also shows that accountability may extend beyond the owner: Kawa’s sister and main employee, Jennifer Stechkober, received a 16-month prison sentence after the court found that she played an integral role in the business and its false statements. The US attorney described the sentences as intended to send a deterrent message, and attorney David Holt characterized the case as a wake-up call for other RUO companies because it involved actual prison time rather than merely a cease-and-desist or other civil sanction. For the broader peptide market, those outcomes signal that regulators and prosecutors may pursue individual accountability and meaningful monetary penalties when RUO disclaimers are contradicted by evidence of intended human use.

Online sellers, compounders, prescribers, and marketers active in the peptide space should:

• Audit websites and marketing materials against FDA’s intended-use standard; an RUO disclaimer will not overcome dosing, injection, or human-use content.
• Ensure certificates of analysis and safety claims are accurate and current; misrepresentation of test results has drawn criminal charges.
• Monitor FDA warning letters and state actions against other online sellers, compounders, prescribers, and marketers of peptides.
• Consult counsel before marketing, prescribing, or compounding any peptide not clearly authorized for its intended use.

We will continue to monitor FDA’s enforcement actions and regulatory signals concerning peptide products. If you have questions about how these developments may affect your business, please contact a member of McDermott Will & Schulte’s Life Sciences FDA, Global Regulatory & Market Access.