The Amino-zing World of Peptide Regulation

For anyone contemplating entering the peptide market, the threshold question is existential: in the current environment, is your business model viable or even legal? The answer depends entirely on which regulatory lane you occupy — and whether you have one at all.

So What Is a Peptide, Exactly?

A peptide is a short chain of amino acids — the same building blocks that make up proteins — linked by peptide bonds. String together a handful of amino acids (roughly two to 50), and you have a peptide; string together more, and you have a protein. What makes certain peptides therapeutically interesting is their ability to mimic or modulate biological signaling. Insulin, the granddaddy of peptide therapeutics, has been keeping diabetics healthy for over a century. 

Over the last five years, GLP-1 receptor agonists — semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — ignited the modern peptide craze by demonstrating dramatic efficacy for diabetes and obesity. Meanwhile, peptides like BPC-157, TB-500, CJC-1295, and ipamorelin have built diehard followings in the wellness world despite lacking US Food and Drug Administration (FDA) approval for any indication. Here is the catch: saying you are “taking peptides” or “taking Glow Stack” is about as informative as saying you are “taking chemicals.” The category is vast, the science is uneven, and the market has raced well ahead of both.

The FDA’s Current Position

In March, the FDA issued 30 Warning Letters to telehealth companies offering GLP-1 products with misleading claims. In April, another round of Warning Letters landed, this time targeting companies marketing unapproved GLP-1, dual GLP-1/GIP, and triple agonist products, many labeled “research use only” (RUO). State regulators are following suit. The Ohio Board of Pharmacy, for example, has targeted clinics and distributors handling unapproved peptide products. The message is unmistakable: the RUO label is not a protective regulatory force field, and the absence of enforcement yesterday is no guarantee of tolerance tomorrow. 

The FDA does not have a special “peptide” regulatory classification. Any peptide intended for the diagnosis, cure, treatment, or prevention of disease, or intended to affect the body’s structure or function, is a drug under the Federal Food, Drug, and Cosmetic (FD&C) Act. Full stop. That means the default pathway to market is the same gauntlet every pharmaceutical faces: preclinical studies, Investigational New Drug (IND) applications, phased clinical trials, and a New Drug Application (NDA) (or an Abbreviated New Drug Application (ANDA) for generics). 

Compounders — pharmacies that mix raw ingredients to create customized medications rather than dispensing commercially manufactured drugs — however, operate under a separate framework. Sections 503A and 503B of the FD&C Act allow pharmacies and registered outsourcing facilities (facilities registered with the FDA under Section 503B that may compound larger volumes of drugs without individual patient prescriptions), respectively, to compound customized medications — but not copies of commercially available drugs, unless those drugs are on the FDA’s shortage list (a publicly available, regularly updated database identifying drugs whose national supply cannot meet current demand). The FDA also categorizes which bulk drug substances compounders may use when creating custom medications, and in late 2023, the agency flagged 19 popular peptides — BPC-157, TB-500, and others — as Category 2 (an FDA designation for bulk drug substances that present significant safety concerns and may no longer be used in compounding), effectively banning them from traditional compounding. 

The FDA, through multiple offices and centers, has emerged as a frontline enforcer in this space, issuing successive waves of Warning Letters targeting peptide compounding, marketing claims, and related practices as the peptide market has proliferated far faster than ever before.

A Tense Supply Chain, an Evolving FDA

The FDA’s actions have been met with market and legal protest, with advocates and companies alleging overreach through lawsuits.

Where you sit in the peptide supply chain determines how the law treats you, and right now, every seat is uncomfortable. Approved manufacturers like Eli Lilly and Novo Nordisk invested billions to earn their NDAs and Biologics License Applications (BLAs). Compounders argue they filled a genuine access gap when GLP-1 drugs entered shortage, serving millions of patients at a fraction of the price. And online sellers? Many apply RUO stickers on their products —wrongly thinking RUO is a blanket lab label that turns a drug into a mere chemical — and assume that puts them outside FDA regulations; it does not.

Compounding pharmacies entered the GLP-1 market in 2022 when demand for semaglutide and tirzepatide outstripped supply and both drugs hit the FDA Drug Shortage List, thereby permitting compounders to produce copies at a fraction of brand-name prices. A multibillion-dollar sub-industry emerged almost overnight, fueled by telehealth startups like Hims & Hers. But by early 2025, the FDA declared both shortages resolved, pulling the legal basis for compounding. 

As noted above, in late 2023 the FDA moved 17 peptides popular among longevity enthusiasts — BPC-157, TB-500, and others — into Category 2, banning them from compounding, while a gray market of self-proclaimed RUO sellers continued operating behind disclaimers the FDA does not recognize for these products as they are being promoted. Under US Department of Health and Human Services Secretary Kennedy’s Make America Healthy Again (MAHA) agenda, the FDA now plans to reconsider 12 of those 17 peptides at a July 2026 advisory committee meeting. The current situation has resulted in a volatile mix of active litigation, deregulatory pressure, massive market demand, and unresolved safety questions — a landscape where every participant is operating with at least some uncertainty.

The Fifth Circuit Showdown: OFA v. FDA

This multi-front tension has produced a landmark case now before the Fifth Circuit: Outsourcing Facilities Association v. FDA (Case Nos. 25-10600 and 25-10758). When the FDA declared the tirzepatide shortage resolved in late 2024, it effectively flipped a switch — conduct that was lawful one day became unlawful the next, with no notice, no comment period, and did not target any specific person, company, or entity. OFA and compounder FarmaKeio sued the agency, arguing that this was rulemaking dressed up as adjudication in violation of the Administrative Procedure Act (APA). The district court sided with the FDA, reasoning that requiring notice-and-comment rulemaking for shortage determinations would render them stale before the ink dried. At oral argument on March 25, the compounders’ counsel called the FDA’s action “a prospective legal prohibition on compounding for an entire industry” — a “party-free adjudication” without precedent in APA history. The Fifth Circuit panel has not yet ruled. 

Looking Ahead

The peptide market sits at a rare intersection of competing forces: an evolving regulatory framework that has yet to settle, surging consumer and clinical demand, a vocal Administration signaling deregulatory intent, and a robust public discourse amplified by social media and the longevity startup boom. Litigation is active, agency guidance is in flux while at the same time its enforcement is robust, and market participants from Big Pharma to compounding pharmacies to telehealth startups are all operating with legal uncertainty. For now, the prevailing posture across the industry is one of cautious patience — stay the course, monitor the Fifth Circuit and the July 2026 advisory committee meeting, and prepare to pivot quickly once the dust begins to settle.