WADA's Prohibited Peptide List: Every Banned Peptide

Peptides and Anti-Doping

S2

Category S2 of WADA's Prohibited List covers peptide hormones, growth factors, and mimetics. It is the most peptide-dense section of the banned substance code.

WADA 2026 Prohibited List, effective January 1, 2026

WADA 2026 Prohibited List, effective January 1, 2026

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The World Anti-Doping Agency (WADA) maintains a Prohibited List updated every January. Category S2, "Peptide Hormones, Growth Factors, Related Substances and Mimetics," is where most peptides discussed on RethinkPeptides fall. These substances are banned at all times (in-competition and out-of-competition) and classified as "non-specified," meaning athletes face the strictest penalties for violations. This article maps every peptide and peptide-adjacent substance on the 2026 list. For details on how these substances are detected, see the peptide doping detection article. For specific banned peptides, see the articles on BPC-157 and TB-500 in sports, GLP-1 agonists and WADA, and growth hormone secretagogues.

The Structure of the WADA Prohibited List

WADA's list is divided into substances prohibited at all times, substances prohibited in-competition only, and prohibited methods. Peptides appear primarily in two sections:

• S2: Peptide Hormones, Growth Factors, Related Substances and Mimetics (prohibited at all times)
• S4: Hormone and Metabolic Modulators (includes some peptide-adjacent substances)

All S2 substances are "non-specified," meaning WADA considers them performance-enhancing by nature. Athletes who test positive face a default four-year ban (reduced to two years only if they can prove the violation was not intentional). There is no accidental ingestion defense for substances like GHRP-6 or EPO.

S2.1: Erythropoietins and Agents Affecting Erythropoiesis

This subcategory targets blood-boosting peptides. The headline substance is erythropoietin (EPO), the 165-amino-acid glycoprotein hormone that stimulates red blood cell production.

Banned substances include:

• Erythropoietin (EPO) and all recombinant forms (epoetin alfa, epoetin beta)
• Darbepoetin (dEPO), a modified EPO with a longer half-life
• EPO-based constructs (EPO-Fc, CERA/methoxy polyethylene glycol-epoetin beta)
• EPO-mimetic peptides and constructs (peginesatide, pegmolesatide, CNTO-530)
• Hypoxia-inducible factor (HIF) activators: roxadustat, daprodustat, molidustat, vadadustat
• Even xenon and cobalt are banned because they activate HIF pathways

EPO doping became infamous through professional cycling in the 1990s and 2000s. The EPO test, developed by Françoise Lasne and Jacques de Ceaurriz, detects differences in the isoelectric focusing pattern between endogenous and recombinant EPO. Newer EPO variants like CERA and biosimilars have forced continuous analytical evolution.

S2.2: Peptide Hormones and Their Releasing Factors

This is the broadest peptide category. It bans all forms of the following hormone systems:

Growth Hormone (GH)

Banned: GH itself, all analogs (lonapegsomatropin, somapacitan, somatrogon), and GH fragments including AOD-9604 and hGH 176-191. The inclusion of AOD-9604 is relevant to the peptide community because this GH fragment has been marketed as a fat-loss peptide. WADA considers it prohibited regardless of whether it actually enhances performance.

Growth Hormone Secretagogues (GHS)

This subcategory is the most directly relevant to peptide users. Every GH secretagogue and GH-releasing peptide is banned:

• Non-peptide secretagogues: anamorelin, capromorelin, ibutamoren (MK-677), macimorelin, tabimorelin
• GH-releasing peptides (GHRPs): alexamorelin, examorelin (hexarelin), GHRP-1, GHRP-2 (pralmorelin), GHRP-3, GHRP-4, GHRP-5, GHRP-6
• Other: ipamorelin, lenomorelin (ghrelin)

The list uses "e.g." language, meaning these are examples. Any substance that stimulates GH release through the ghrelin receptor (GHSR) or any other GH-releasing pathway is prohibited, even if it is not explicitly named.

Thomas et al. (2011) described methods for detecting GHRPs and their metabolites in human urine, using liquid chromatography-mass spectrometry (LC-MS/MS). The challenge is that peptides like GHRP-2 and GHRP-6 are rapidly metabolized, with parent compounds detectable for only hours after administration. Detection strategies increasingly focus on metabolites with longer urinary detection windows.^[1]

GnRH and Gonadotropins (Males Only)

In male athletes, the following are banned:

• GnRH (gonadorelin) and agonist analogs: buserelin, deslorelin, goserelin, histrelin, leuprorelin, nafarelin, triptorelin
• Luteinizing hormone (LH) and human chorionic gonadotropin (hCG)

These are banned in males because they stimulate testosterone production. In females, GnRH agonists are used therapeutically for conditions like endometriosis and are not banned.

Corticotropins

ACTH (corticotropin), corticorelin, and tetracosactide (a synthetic ACTH analog) are prohibited. These stimulate cortisol release from the adrenal glands. While cortisol is catabolic (not anabolic), ACTH's effects on other adrenal hormones and its use in masking other substances led to its inclusion.

Insulins and Insulin Mimetics

All insulins (human, animal, synthetic analogs) are banned for athletes without a documented diabetes diagnosis. Athletes with type 1 diabetes can obtain a Therapeutic Use Exemption (TUE).

S2.3: Growth Factors and Growth Factor Modulators

This subcategory bans peptide growth factors that affect:

• Muscle protein synthesis/degradation
• Tendon or ligament repair
• Vascularization
• Energy utilization
• Regenerative capacity
• Fiber type switching

Explicitly named substances include:

• Thymosin beta-4 and derivatives (e.g., TB-500): TB-500 is a synthetic fragment of thymosin beta-4, widely used in the peptide community for injury recovery. It is explicitly prohibited. The BPC-157 and TB-500 in sports article covers the anti-doping implications in detail.
• Fibroblast growth factors (FGFs)
• Hepatocyte growth factor (HGF)
• Insulin-like growth factor 1 (IGF-1) and all analogs
• Mechano growth factors (MGFs)
• Platelet-derived growth factor (PDGF)
• Vascular endothelial growth factor (VEGF)

Again, the "e.g." language means this list is not exhaustive. Any growth factor that affects muscle, tendon, or recovery processes is prohibited.

What About BPC-157?

BPC-157 occupies a gray area. It is not explicitly named on the 2026 Prohibited List. However, WADA's S2.3 category bans all growth factors affecting tendon, ligament, or muscle regeneration. BPC-157's primary research profile involves wound healing, tendon repair, and tissue regeneration, which falls squarely within the S2.3 definition.

Most anti-doping authorities interpret BPC-157 as prohibited under the catch-all language. Athletes have been sanctioned for BPC-157 use. The practical position is: if it promotes tissue repair, WADA considers it banned, whether named or not. See the BPC-157 and TB-500 anti-doping article for a full analysis.

What About GLP-1 Agonists?

Semaglutide, tirzepatide, and other GLP-1 receptor agonists are not on the 2026 Prohibited List. They do not enhance performance through any of the S2 mechanisms (they do not increase GH, EPO, testosterone, or growth factors). The GLP-1 agonists and WADA article discusses whether weight loss itself could become a fairness concern in weight-class sports, but as of 2026, these drugs are not prohibited.

Detection Challenges: Why Peptide Doping Is Hard to Catch

Detecting peptide doping is fundamentally harder than detecting steroid doping. Steroids are small, stable molecules that persist in urine for days to weeks. Peptides are larger, unstable, and rapidly degraded.

Barroso et al. (2012) reviewed the analytical challenges and identified several key problems:^[2]

• Short detection windows. GHRPs are cleared from urine within hours. An athlete who injects GHRP-2 in the evening may test clean by morning.
• Low concentrations. Peptide hormones circulate at picogram-per-milliliter levels, requiring extremely sensitive analytical methods.
• Endogenous interference. Many banned peptides (GH, EPO, insulin) are also produced naturally. Tests must distinguish exogenous administration from normal production.
• Rapid evolution. New peptide analogs and secretagogues are developed faster than validated detection methods can be established.

The response has been twofold. Direct detection methods using LC-MS/MS can identify specific peptides and their metabolites in blood and urine. Indirect methods (biomarker approaches) look for downstream biological changes. The GH biomarker test, for example, measures the ratio of different GH isoforms: recombinant GH is a single isoform (22 kDa), while endogenous GH is a mixture. An altered ratio suggests exogenous use.

The Athlete Biological Passport (ABP) takes this further by tracking an individual athlete's hematological and endocrine parameters over time. Sudden changes in IGF-1, hematocrit, or reticulocyte count can trigger targeted testing even without a positive direct test.

Therapeutic Use Exemptions for Peptide Hormones

Athletes with legitimate medical conditions can apply for a Therapeutic Use Exemption (TUE) to use prohibited substances. For peptide hormones, the most common TUE scenarios are:

• Insulin for athletes with type 1 diabetes. The TUE process requires documented diagnosis and ongoing monitoring. Insulin TUEs are relatively straightforward because the medical need is clear and the condition is easily verified.
• Growth hormone for athletes with documented adult GH deficiency. These TUEs are rare and require extensive endocrine testing to confirm the diagnosis. The GH biomarker test must account for therapeutic GH levels.
• EPO for athletes with chronic kidney disease or certain anemias. These are extremely rare in competitive athletes.

TUEs are not available for GH secretagogues (MK-677, ipamorelin, GHRPs), TB-500, AOD-9604, or any substance used primarily for performance or recovery enhancement rather than treatment of a diagnosed disease. An athlete cannot obtain a TUE for GHRP-6 to assist with injury recovery, even with a physician's prescription. The distinction WADA draws is between treating a medical condition and enhancing athletic performance or recovery.

The Gray Zone: Peptides WADA Is Watching

WADA's Monitoring Program tracks substances that are not yet prohibited but are under surveillance for potential future inclusion. This program collects data on the prevalence of use without penalizing athletes.

Substances that have appeared on or been discussed in the context of the monitoring program include certain selective androgen receptor modulators (SARMs) and newer metabolic peptides. The monitoring program is how WADA gathers evidence before deciding whether a substance meets the three criteria for prohibition: performance enhancement, health risk, and violation of the spirit of sport. A substance must meet at least two of these three criteria to be added to the prohibited list.

For peptide researchers, the monitoring program is the leading indicator. If a novel peptide starts showing up in athlete biological samples and the research literature suggests performance-enhancing potential, it will likely be added to the prohibited list within one to two annual update cycles.

The 2026 Updates

The 2026 list, approved by WADA's Executive Committee on September 11, 2025, added further clarifications and examples within the S2 category. New GH analogs (lonapegsomatropin, somapacitan, somatrogon) were explicitly named, reflecting their recent clinical approvals. The examples lists for GHRPs and GHS were also expanded to reduce ambiguity.

The monitoring program (substances WADA tracks but has not yet banned) continues to evaluate emerging compounds. This is where newer peptides may appear before being formally prohibited.

The practical implication for athletes is straightforward: if a peptide affects growth hormone, red blood cell production, testosterone, or tissue repair, assume it is banned. The "e.g." language throughout S2 means WADA does not need to name a substance specifically to prohibit it. The burden falls on the athlete to verify that any substance they use is not covered by the category-level prohibitions, regardless of whether it appears on a named list. Anti-doping violations carry strict liability: an athlete is responsible for what is in their body, regardless of intent, knowledge, or how the substance got there.

The Bottom Line

WADA's 2026 Prohibited List bans dozens of peptides and peptide-adjacent substances under category S2, including all forms of EPO, growth hormone, GH secretagogues (MK-677, ipamorelin, GHRP-2, GHRP-6, hexarelin), GnRH agonists in males, insulin, and growth factors including TB-500. BPC-157 is not named but is widely interpreted as prohibited under catch-all language. GLP-1 agonists remain permitted. Detection relies on mass spectrometry and biomarker approaches, with short detection windows being the primary challenge for peptide-specific testing.

Frequently Asked Questions

What peptides are banned by WADA?

WADA bans all growth hormone secretagogues (MK-677, ipamorelin, GHRP-2, GHRP-6, hexarelin, ghrelin), growth hormone and its fragments (AOD-9604, hGH 176-191), EPO and erythropoiesis-stimulating agents, TB-500 (thymosin beta-4 derivative), insulin (without a TUE), GnRH agonists in males, and all growth factors affecting muscle, tendon, or recovery. These are prohibited at all times, in and out of competition.

Is BPC-157 banned in sports?

BPC-157 is not explicitly named on the 2026 WADA Prohibited List. However, WADA's S2.3 category bans all growth factors affecting tendon, ligament, or muscle regeneration, which describes BPC-157's research profile. Most anti-doping authorities interpret BPC-157 as prohibited, and athletes have been sanctioned for its use.

Is MK-677 (ibutamoren) banned in sports?

MK-677 (ibutamoren) is explicitly named on the WADA Prohibited List under S2.2 as a growth hormone secretagogue. It is banned at all times, in and out of competition, and classified as a non-specified substance, meaning a positive test carries a default four-year suspension.

Are GLP-1 drugs like semaglutide banned by WADA?

GLP-1 receptor agonists including semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) are not on the 2026 WADA Prohibited List. They do not enhance performance through any banned mechanism. Whether weight loss drugs create fairness concerns in weight-class sports is a separate question that anti-doping authorities are monitoring.

How long can peptide doping be detected?

Detection windows for peptides are short compared to steroids. GHRPs like GHRP-2 may be detectable in urine for only hours after injection (Thomas et al., 2011). The GH biomarker test extends the window to 24-48 hours. The Athlete Biological Passport can flag suspicious patterns over weeks or months through indirect markers like IGF-1, hematocrit, and reticulocyte count.

What happens if an athlete tests positive for a banned peptide?

Peptides in WADA's S2 category are classified as non-specified substances, carrying a default four-year suspension for a first violation. This can be reduced to two years if the athlete proves the violation was not intentional. Second violations carry up to eight years. All results from competitions around the time of the violation are typically disqualified.