WADA Prohibited List: Peptide Categories Banned in Sport

TL;DR: The World Anti-Doping Agency (WADA) Prohibited List bans peptides under two primary sections: S0 (Non-Approved Substances, any compound not approved by a regulatory authority for human therapeutic use, which captures most research-only peptides) and S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics, explicitly covering EPO/erythropoietins, growth hormone, GH-releasing peptides such as GHRP-6 and ipamorelin, GHRH analogs such as CJC-1295, sermorelin and tesamorelin, IGF-1, mechano growth factors, and related analogs). Both sections apply at all times, in-competition and out-of-competition.

Research-Use Disclaimer: This article is for educational and research reference purposes only. The compounds referenced are research chemicals not approved by the FDA for human use. This content does not constitute medical advice, does not recommend or endorse human administration of any compound, and does not describe protocols for personal use. For adults 21+ with a research interest only.

How the WADA Prohibited List Works: Structure and Legal Force

The World Anti-Doping Agency (WADA) is an independent foundation established in 1999 to coordinate anti-doping policy across international sport. Its Prohibited List is the central regulatory instrument of the World Anti-Doping Code, the framework to which Olympic sport federations, national anti-doping organizations such as USADA, and most major professional sports bodies are signatories. The List is updated and published annually, entering into force on 1 January of each year.

A substance or method is placed on the Prohibited List when it meets at least two of three criteria defined in the WADA Code: it has the potential to enhance sport performance; it represents an actual or potential health risk to the athlete; or its use violates the spirit of sport. The List does not require proof of performance enhancement in isolation, risk to health or violation of sport spirit can each independently satisfy a criterion. According to a 2008 review by Barroso, Mazzoni, and Rabin of the WADA Science Department, published in the Asian Journal of Andrology, the List is “constantly updated to reflect new developments in the pharmaceutical industry as well as doping trends” and enumerates both substances and methods prohibited in- and out-of-competition (DOI: 10.1111/j.1745-7262.2008.00402.x).

The List is organized into sections. Substances prohibited at all times (Sections S0–S5 and M1–M3) apply regardless of whether an athlete is in or out of competition. Substances prohibited in-competition only (Sections S6–S9) carry a defined competition window, typically beginning at midnight before the event. Peptides relevant to research contexts appear primarily in Section S0 and Section S2, both of which are always-prohibited.

Section S0: Non-Approved Substances, The Catch-All Category

Section S0 is the broadest and most consequential category for research peptides. It prohibits any pharmacological substance that is not currently approved by any governmental regulatory authority for human therapeutic use, for any indication, in any country, in any dose form. This includes compounds under active clinical investigation, compounds that failed to gain approval, and compounds that have never entered the regulatory pathway at all.

The practical implication is sweeping: a peptide does not need to be explicitly named on the Prohibited List to be banned under S0. If no governmental regulatory body, the U.S. FDA, the European Medicines Agency, Health Canada, or equivalent, has authorized the substance for human therapeutic use, S0 applies automatically. The prohibition is not contingent on detection capability, evidence of performance enhancement, or any other threshold beyond regulatory status.

Compounds commonly discussed in research peptide contexts that fall under S0 include:

• BPC-157, not approved by any regulatory authority for human use; explicitly listed under S0 on the WADA Prohibited List
• TB-500 (Thymosin Beta-4 fragment), not approved for human therapeutic use
• Epithalon (Epitalon), not approved; no regulatory authorization in any jurisdiction
• PT-141 (Bremelanotide), note: FDA approved Vyleesi (bremelanotide) for hypoactive sexual desire disorder in 2019; research-grade PT-141 is a separate commercial category, athletes should verify current WADA status directly via GlobalDRO
• Any novel peptide or research compound without current regulatory approval in any jurisdiction

S0 applies at all times, both in-competition and out-of-competition. A Therapeutic Use Exemption (TUE) cannot be granted for an S0 substance, because TUEs require an approved medical indication and an approved substance; S0 compounds by definition have neither.

Section S2: Peptide Hormones, Growth Factors, Related Substances and Mimetics

Section S2 is the named-substance section for peptides that operate within or mimic the growth hormone and related axes. Unlike S0, S2 explicitly enumerates categories and examples of prohibited compounds. Researchers studying compounds in the GH-axis or hematopoietic space need to be familiar with S2’s subcategories, because the coverage is broad, extends to analogs and mimetics, and includes compounds that do have some regulatory history.

The 2025 WADA Prohibited List organizes S2 into the following subcategories, all prohibited at all times:

S2.1, Erythropoiesis-Stimulating Agents (ESAs)

This subcategory includes erythropoietins (EPO) and their analogs, compounds that stimulate red blood cell production and increase oxygen-carrying capacity. EPO (epoetin alfa, darbepoetin alfa, and related agents) are explicitly named. Gene-doping approaches targeting erythropoiesis also fall within WADA’s prohibited methods. A 2006 review by Haisma and de Hon in the International Journal of Sports Medicine noted that WADA and the IOC had classified gene doping, including EPO gene transfer, as a prohibited method, recognizing that recombinant technologies were making these approaches increasingly accessible (DOI: 10.1055/s-2006-923986).

S2.2, Peptide Hormones and Their Releasing Factors

This is the subcategory most directly relevant to the GH-axis research peptide space. It covers growth hormone (GH) and all GH-releasing factors, the compounds that stimulate endogenous GH secretion. The 2025 WADA Prohibited List explicitly names and prohibits the following classes and examples:

• Growth Hormone-Releasing Hormone (GHRH) and its analogs: sermorelin, CJC-1295 (with and without DAC), tesamorelin, and related GHRH mimetics. These compounds act at the GHRH receptor on pituitary somatotrophs to stimulate GH release.
• Growth Hormone-Releasing Peptides (GHRPs) and Growth Hormone Secretagogues (GHS): GHRP-6, GHRP-2, ipamorelin, hexarelin, and related compounds. These act primarily via the ghrelin receptor (GHS-R1a) to stimulate GH pulse amplitude.
• Growth Hormone (somatotropin/hGH) itself, including recombinant forms (rhGH) and all GH analogs.

The analytical doping-control challenge posed by these peptides has been documented in the peer-reviewed literature. A 2022 study by Thomas, Thilmany, Hofmann, and Thevis at the German Sport University Cologne’s Center for Preventive Doping Research, published in Analytical Science Advances, developed a blood-based detection method capable of simultaneously identifying sermorelin, CJC-1295, tesamorelin, and multiple IGF-1 and MGF variants in post-administration samples, using liquid chromatography coupled to high-resolution mass spectrometry meeting WADA’s TD2022 MRPL (Minimum Required Performance Levels) documents (DOI: 10.1002/ansa.202200027). The study confirms that these compounds are explicitly recognized as banned in elite sport and that validated analytical testing procedures now exist for their detection.

S2.3, Insulin-Like Growth Factors and Analogs

Section S2 also explicitly prohibits insulin-like growth factor 1 (IGF-1) and its analogs, including:

• IGF-1 (somatomedin C), the primary mediator of GH’s anabolic effects, produced mainly in the liver
• Long-R-IGF-I, R-IGF-I, Des-IGF-I, modified analogs with altered binding characteristics
• Mechano Growth Factor (MGF), a splice variant of the IGF-1 gene expressed in mechanically stressed muscle tissue; the human MGF sequence and the synthetic Goldspink variant (PEG-MGF) are both explicitly recognized in anti-doping literature and subject to the S2 prohibition

Thomas et al. (2022) specifically confirmed the detection of human MGF and MGF-Goldspink in their blood doping control method, underscoring that these splice variants of IGF-1 are within the analytical scope of WADA-accredited laboratories.

S2.4, Other Growth Factors and Mimetics

S2 also covers a broader prohibition on growth factors and their mimetics that can affect muscle, tendon, or ligament repair capacity, or influence erythropoiesis or vascular biology. This includes fibroblast growth factors (FGFs), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), thymosin-beta 4 (TB-4) and its derivatives, and platelet-derived growth factor (PDGF). The category explicitly extends to “any substance with similar chemical structure or similar biological effects.” This “similar biological effects” language is significant: it is the mechanism by which novel compounds not yet named can still be captured under S2.

Peptide Classification Summary: S0 vs. S2

Why “Research Use Only” Peptides Still Appear on the WADA List

A question that frequently arises in research-peptide contexts is why WADA would prohibit compounds that carry “research use only” labels, have no approved medical indications, and are not legally available for human use. The answer lies in three intersecting realities.

1. Regulatory Label Does Not Limit Pharmacological Effect

A compound’s commercial or legal classification, research-use only, investigational new drug, unapproved, is entirely separate from its pharmacological activity. A growth hormone secretagogue that binds GHS-R1a and triggers GH release in rodent models will have the same receptor pharmacology in a human pituitary, regardless of how the compound is labeled in commerce. WADA’s prohibition is based on biological mechanism and performance-enhancement potential, not regulatory category.

2. Documented Availability and Use in Sport

The peer-reviewed anti-doping literature documents that research peptides and unapproved substances have historically entered competitive sport before regulatory agencies classify or respond to them. The Barroso et al. (2008) review from WADA’s own Science Department explicitly noted that “drugs that are still in the experimental phases of research may find their way into the athletic world”, a pattern observed across multiple compound classes over decades. The S0 category was specifically designed to address this: a substance does not need to be found in a positive test before WADA prohibits it. Prohibition is prospective and categorical.

3. The “Similar Biological Effects” Extension

As noted above, Section S2’s language explicitly extends to any substance with similar biological effects to named compounds. This means that a novel peptide secretagogue structurally distinct from ipamorelin but functionally equivalent, stimulating GH release via GHS-R1a, is prohibited under S2 even if it has never been tested for in an actual doping control sample. The category covers mechanism, not just molecules.

How to Assess WADA Status When Reviewing a Compound

Researchers who work in contexts where WADA compliance is relevant, sports science, clinical research involving athlete populations, or educational reference work, should apply a consistent framework when evaluating a compound’s status.

1. Check regulatory approval status first. If the compound has no approval from any governmental regulatory authority for any human therapeutic indication, S0 applies automatically. Most research-grade peptides fail this threshold and are prohibited under S0 without requiring further analysis.
2. Check S2 subcategories for named or analogous compounds. If a compound is a growth hormone-releasing peptide, a GHRH analog, an IGF-1 variant, a mechano growth factor, an erythropoietin mimic, or a growth factor with similar biological effects to named agents, it falls under S2 regardless of S0 status.
3. Use GlobalDRO.com for verification. GlobalDRO (globaldro.com), maintained by USADA and its international partners, allows researchers to check the WADA prohibited status of specific substances by name, sport, and nation. It is updated to reflect the current Prohibited List. For any specific substance, GlobalDRO is the authoritative lookup tool.
4. Consult the current WADA Prohibited List directly. The Prohibited List is published annually at wada-ama.org. Because the list is updated each year and enters into force on 1 January, researchers should verify against the most current version rather than relying on prior-year documentation.
5. Do not rely on commercial labeling. A “research use only” label, a disclaimer on a vendor website, or a compound’s presence in a research catalog does not affect WADA status in either direction. Status is determined by the substance’s pharmacological properties and regulatory history, not its point-of-sale classification.

A Note on Therapeutic Use Exemptions (TUEs)

Athletes who require a medically necessary prohibited substance may apply for a Therapeutic Use Exemption (TUE) through their national anti-doping organization. A TUE requires: (1) that the condition being treated is a diagnosed medical necessity; (2) that the therapeutic use will not produce a significant performance enhancement beyond restoration to normal health; (3) that no reasonable permitted alternative treatment exists; and (4) that the substance is approved for the therapeutic use in question. This last criterion structurally excludes S0 substances: a TUE cannot be granted for a compound with no approved indication, because there is no approved therapeutic context in which to ground the exemption. S2 substances that do have regulatory approval (for example, recombinant GH prescribed for documented adult GH deficiency) may be eligible for TUE consideration through the proper clinical pathway.

Frequently Asked Questions About WADA and Peptides

Which peptides are banned by WADA?

The WADA Prohibited List bans peptides under two primary sections. Section S0 automatically prohibits any pharmacological substance not approved by a regulatory authority for human therapeutic use, capturing most research-only peptides including BPC-157 and TB-500. Section S2 explicitly names and prohibits erythropoietins (EPO), growth hormone (GH) and GH-releasing factors (including GHRPs such as GHRP-6 and ipamorelin, and GHRH analogs such as CJC-1295, sermorelin, and tesamorelin), IGF-1 and analogs, mechano growth factors (MGF), and growth factors with similar biological effects. Both sections are prohibited at all times, in-competition and out-of-competition.

What is Section S0 on the WADA Prohibited List?

Section S0 is a categorical prohibition covering any pharmacological substance not currently approved by any governmental regulatory authority for human therapeutic use in any jurisdiction. It is prospective, a compound does not need to be detected in a positive test before it is prohibited. S0 applies at all times, and no TUE can be granted for an S0 substance. The vast majority of research-only peptides fall under S0.

Does “research use only” labeling exempt a peptide from WADA prohibition?

No. WADA prohibition is based on the compound’s pharmacological properties and regulatory approval status, not on its commercial label. A research-only peptide that lacks regulatory approval is automatically captured by S0 regardless of how it is labeled, sold, or intended to be used.

What is the difference between in-competition and out-of-competition WADA prohibition?

Substances prohibited at all times (including all S0 and S2 peptides) apply regardless of competition timing, athletes cannot use them at any point during the year. In-competition-only prohibitions (stimulants, cannabinoids, glucocorticoids) apply only within a defined window around a specific event. Because S0 and S2 are always-prohibited, athletes subject to WADA rules are bound by these restrictions year-round, not just on competition days.

For educational and research reference purposes only. Not medical advice. Not for human use.