Eli Lilly and Company (“Lilly”) filed six federal lawsuits on August 12, 2026, against businesses it accuses of illegally selling retatrutide, the company’s experimental “triple-agonist” obesity drug that has not yet been approved by the U.S. Food and Drug Administration (FDA) or any other regulator worldwide.[1] The defendants include four “Research-Use-Only” (RUO) sellers, a med spa, and a compounding pharmacy.
In each of the lawsuits, Lilly asks the court for a permanent injunction barring the defendant from manufacturing, marketing, distributing, dispensing, or selling any product containing or purporting to contain retatrutide, as well as for disgorgement of profits and attorney’s fees.
The suits mark the first time Lilly has targeted RUO sellers in efforts to protect its brand and products.
The Lawsuits: Who, What, and Where
There is no lawful retail, pharmacy, or wellness distribution channel for retatrutide, and the FDA has stated that retatrutide “cannot be used in compounding under federal law.”[2]
Retatrutide is a triple hormone agonist that targets three separate hormone receptors (GLP-1, GIP, and glucagon), a mechanism for which Lilly has evidence of greater effectiveness for weight loss than its currently marketed drugs, Zepbound and Mounjaro, in clinical trials.[3] It is currently in Phase 3 clinical trials, but Lilly does not expect to submit an FDA application for approval of the drug until 2027.[4] This means retatrutide can only be accessed through Lilly-sponsored clinical trials or, in narrow circumstances, through the FDA’s expanded access framework, and cannot be legally sold to any patient in the United States.
In the lawsuits, Lilly alleges that the defendants sold retatrutide-containing products to consumers for weight loss through direct marketing, med-spa administration, and online storefronts. The four RUO sellers labeled their products “research use only,” a designation reserved for laboratory and research applications, not human use, while marketing them in ways Lilly alleges were directed at human use.[5] Against the med spa defendant, the complaint alleges that it openly advertised its “Triple G” retatrutide product on its website and social media, while the complaint against the pharmacy alleges that it unlawfully sells illegal retatrutide to medical spas and providers.[6]
The company frames the defendants’ conduct bluntly, stating that these “medical spas,” “wellness clinics,” and self-styled suppliers “are not practicing medicine; they are selling illegal drugs.”[7] Lilly further contends that because the products are entirely unregulated, they may be fake, impure, or mis-dosed, creating significant safety risks for consumers who inject them.[8] The six cases were filed in four different federal district courts in Texas.
These six lawsuits are only the visible tip of a much larger enforcement effort. To date, Lilly reports it has referred more than 200 individuals and entities to the FDA, the U.S. Department of Justice (DOJ), state attorneys general, law enforcement, and professional licensing boards, and has flagged more than 14,000 websites, advertisements, and social media listings offering retatrutide worldwide.[9]
Analyzing the Causes of Action
What is notable to practitioners is what Lilly did not plead in most of these cases. These complaints do not assert patent infringement, and they do not rely on the Lanham Act or federal trademark claims. Instead, Lilly is proceeding almost entirely under state-law unfair competition and consumer protection statutes, pointing to deceptive trade practices laws in Texas, Tennessee, Washington, North Carolina, South Carolina, Colorado, Connecticut, and Alaska.[10] The only federal cause of action that asserts a false or misleading advertising claim under the Lanham Act is against Aesthetic Envy, a med spa, for allegedly advertising the benefits of its “Triple G” therapies on its website and social media.[11]
That choice reflects a structural reality of federal drug law: the Food, Drug, and Cosmetic Act (FDCA) does not create a general private right of action, so a competitor cannot sue directly for a violation of the FDCA’s misbranding or new-drug provisions. State unfair competition and consumer protection statutes can provide alternative causes of action based on allegedly deceptive or unlawful commercial conduct. Many of these statutes allow a plaintiff to premise liability on an “unlawful” act that implicates another regulatory scheme, or on the deceptive nature of marketing a research-use-only product for human self-administration. By anchoring the claims in alleged deception, including alleged mislabeling, false “RUO” designations, and marketing that implies safety or efficacy for an unapproved investigational drug, Lilly avoids relying directly on the FDCA’s lack of a private cause of action while still putting the defendants’ alleged regulatory noncompliance squarely at issue.
This is also a lower-friction path than patent litigation. Retatrutide is still under clinical investigation, and its formulation and use patents may not be as fully mapped or litigation-tested as those covering tirzepatide or semaglutide. Consumer protection and unfair competition claims let Lilly move quickly, target marketing conduct directly, and seek broad injunctive relief without opening its patent portfolio to early scrutiny or invalidity challenges.
Importantly, avoiding patent claims may also limit opportunities for defendants to challenge Lilly’s asserted patent rights within these cases. An accused patent infringer may, subject to applicable statutory requirements and deadlines, petition the U.S. Patent and Trademark Office for inter partes review (IPR) before the Patent Trial and Appeal Board (PTAB), challenging certain patent claims based on prior art patents or printed publications. Other mechanisms for challenging patent validity may also be available depending on the circumstances. PTAB proceedings can create significant risk for challenged patent claims. In fiscal year 2025, the all-claims invalidation rate at PTAB was approximately 64%, down from 70% in FY2024 but still representing a significant risk to challenged patent claims.[12] A final determination of unpatentability can have consequences extending beyond the dispute with the particular petitioner because the affected patent claims may ultimately be canceled, subject to rehearing and appellate review. By proceeding primarily under consumer protection and unfair competition theories in these cases, Lilly can focus the litigation on the defendants’ alleged commercial conduct without placing patent infringement and validity directly at issue.
From Cease-and-Desist to the Courthouse
Lilly’s approach to unregulated GLP-1 sales has evolved considerably since late 2023, when Novo Nordisk first sent cease-and-desist letters to dozens of compounding pharmacies producing semaglutide. Lilly followed with its own letters targeting tirzepatide compounders, particularly after the FDA declared the tirzepatide shortage resolved in December 2024 and directed compounders to stop mass-producing copies. Those letters had mixed results. Some pharmacies complied while others, like the telehealth-connected pharmacy OrderlyMeds, publicly dismissed Lilly’s letter as meaning “nothing” to their operations, arguing their formulations were individualized and therefore permissible.[13] That resistance was followed by litigation against telehealth platforms and compounders over tirzepatide and semaglutide in 2024 and 2025.
Even so, those earlier cases operated in a different regulatory context: tirzepatide and semaglutide were, at the relevant times, FDA-approved drugs subject to shortage-based compounding exceptions under Sections 503A and 503B of the FDCA, so the fights were largely about whether a shortage still existed and whether compounded versions were sufficiently “individualized” to qualify for an exemption.
The retatrutide suits are different in kind, not just degree. This is the first time Lilly has taken the research-supply and peptide-vendor channel to court by name, rather than simply referring alleged violators to regulators and letting the FDA or DOJ decide whether to act. The litigation is also over a molecule that has no approved status and, accordingly, is not subject to any compounding exception.
There is no gray zone for the defendants. Retatrutide cannot lawfully be compounded under 503A today because it is not a component of an FDA-approved drug, does not appear on the FDA’s list of bulk drug substances that may be compounded, and lacks a USP or NF monograph. It also cannot be lawfully sold as a finished consumer product under any current regulatory pathway. Notably, the named defendants also skew toward businesses with a consumer-facing marketing posture, including med spas and direct-to-consumer peptide brands, rather than pure wholesale research suppliers, suggesting Lilly’s litigation theory turns heavily on alleged marketing intent and end-use, not merely on who is upstream in the supply chain.
What It Means for RUO Peptide Sellers, Med Spas, and 503A Compounders
For businesses in the RUO peptide and compounding space, the retatrutide suits carry several practical lessons. First, an RUO label is not necessarily a legal shield and such products cannot be marketed or sold for human use. Regulators, and now private litigants, will look past the label to the totality of the marketing claims and surrounding conduct: dosing charts, injection instructions, weight-loss claims, med-spa administration, and consumer-facing sales channels can all be used as evidence that a product was never intended for legitimate research use.
Second, 503A pharmacies should not assume that the legal terrain that applied to tirzepatide or semaglutide compounding, where shortage status created a temporary, defensible compounding pathway, applies to investigational molecules like retatrutide. There is currently no lawful basis to compound an unapproved, still-in-trials drug, and pharmacies that do so are exposed not only to FDA Warning Letters but now to direct civil suits from the innovator company itself, seeking broad and permanent injunctive relief. Similarly, it is unlawful for med spas to market or administer retatrutide-containing products to patients.
Moreover, even if retatrutide is approved in the U.S. next year, there remains a significant regulatory question regarding whether it will be regulated as a drug or a biological product.[14] Lilly has challenged the FDA’s determination regarding retatrutide’s status as a biological product, and a federal court has vacated and remanded part of FDA’s decision concerning whether retatrutide is “analogous” to a protein. If retatrutide ultimately is regulated as a biological product subject to licensure under Section 351 of the Public Health Service Act (PHS Act), the conventional drug-compounding exemptions under Sections 503A and 503B of the FDCA would not provide a pathway for compounding copies of the biological product.
Third, the choice of state consumer protection and unfair competition statutes as the vehicle matters for potential liability and remedies. Depending on the statute and claim at issue, available remedies may include injunctive relief, damages, statutory or enhanced damages, and attorneys’ fees. That presents a materially different risk profile from receiving a cease-and-desist letter alone. Beyond the cost of defending the litigation and potential damages liability, the lawsuits may also increase a defendant company’s public profile in ways that invite additional regulatory scrutiny.
Finally, this litigation should be read as a significant warning to other businesses selling or marketing investigational peptides for human use. Lilly has signaled that retatrutide is a priority enforcement target ahead of its planned 2027 FDA submission, and these lawsuits provide a potential roadmap for future actions against other RUO sellers, pharmacies, and med spas that unlawfully commercialize or market versions of its investigational compound.
How Frier Levitt Can Help
As regulatory scrutiny and private litigation involving peptides continue to grow, stakeholders should reexamine their regulatory status, marketing practices, compounding activities, and overall compliance strategies.
Frier Levitt attorneys with experience in FDA regulatory law and pharmacy law are available to assist clients with strategic advisory, regulatory compliance, and enforcement defense services in the peptide space as regulations and enforcement in this sector continue to evolve.
[1] https://www.law360.com/articles/2512795/lilly-claims-6-vendors-illegally-sold-obesity-drug-candidate
[2] https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss
[3] https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-delivered-powerful-weight-loss
[4] https://www.cnbc.com/2026/07/23/eli-lilly-will-file-for-approval-of-retatrutide-obesity-drug-in-2027.html
[5] Eli Lilly & Co. v. Legendary Peptides, LLC, No. 1:26-cv-00347 (E.D. Tex.); Eli Lilly & Co. v. Lone Star Peptide Co. LLC, No. 4:26-cv-06562 (S.D. Tex.); Eli Lilly & Co. v. Texas Peptides Inc., No. 5:26-cv-05146 (W.D. Tex.); Eli Lilly & Co. v. Astra LLC d/b/a Astra Peptides, No. 5:26-cv-05147-FB (W.D. Tex.).
[6] Eli Lilly & Co. v. Aesthetic Envy Cosmetic Ctrs. LLC, No. 2:26-at-01347 (E.D. Cal.) (med spa); Eli Lilly & Co. v. Striker Pharmacy, LLC, No. 4:26-cv-06563 (S.D. Tex.)
[7] Kristin Jensen, Lilly Files Six Lawsuits in Bid to Shut Down ‘Black Market’ for Retatrutide, BioPharma Dive (Aug. 12, 2026, 11:19 AM), https://www.biopharmadive.com/news/lilly-lawsuit-retatrutide-black-market-obesity-drug/827659/.
[8] Id.
[9] https://investor.lilly.com/node/54816/pdf
[10] Unfair Competition in Violation of the Alaska Unfair Trade Practices and Consumer Protection Act (Alaska Stat. §§ 45.50.471 et seq.; Alaska Stat. § 17.20.110(a)(1)–(2)); Unfair Trade Practices in Violation of the Colorado Consumer Protection Act (Colo. Rev. Stat. § 6-1-105(z); Colo. Rev. Stat. § 12-280-131(1)); Unfair Trade Practices in Violation of the Connecticut Unfair Trade Practices Act (Conn. Gen. Stat. § 42-110b(a); Conn. Gen. Stat. § 21a-110(a)–(b)); Unfair Competition in Violation of the North Carolina Unfair and Deceptive Trade Practices Act (N.C. Gen. Stat. §§ 75-1.1 et seq.; N.C. Gen. Stat. § 106-135); Unfair Competition in Violation of the South Carolina Unfair Trade Practices Act (S.C. Code §§ 39-5-20 et seq.; S.C. Code § 39-23-70); Unfair Competition in Violation of the Tennessee Consumer Protection Act (Tenn. Code §§ 47-18-104 et seq.; Tenn. Code § 53-1-110); Unfair Competition in Violation of Texas Common Law (Tex. Health & Safety Code § 431.114(a)); Unfair Competition in Violation of the Washington Consumer Protection Act (R.C.W. §§ 19.86.010 et seq.; R.C.W. § 69.04.570)
[11] False or Misleading Advertising in violation of Section 43(a)(1)(B) of the Lanham Act, 15 U.S.C. § 1125(a)(1)(B).
[12] IPWatchdog, Perspectives on the PTAB’s 70% All Claims Invalidation Rate (July 2, 2025), https://ipwatchdog.com/2025/07/02/perspectives-ptabs-70-claims-invalidation-rate/
[13] https://finance.yahoo.com/news/orderlymeds-response-eli-lillys-cease-113000352.html
[14] https://news.bloomberglaw.com/health-law-and-business/eli-lilly-sues-to-block-fda-interpretation-of-biological-product
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