Peptide Stack for Endurance Athletes: The Triathlete Protocol, Dosing, and the WADA Reality

In September 2025, a triathlete named Anthony McCauley accepted a four-year USADA suspension. The sanction listed BPC-157, TB-500, CJC-1295, and ipamorelin. Those four compounds appear in virtually every "peptide stack for endurance athletes" guide published this year. None of those guides mention the ban.

This article covers what each peptide actually does, what the most current research shows for endurance specifically, and the one finding that changes how you should think about MOTS-c. If you are subject to anti-doping testing, the WADA section is not optional reading.

What Peptides Are Endurance Athletes Actually Using?

The combination that shows up most often in triathlon and endurance cycling communities includes four compounds. Each has a distinct role in the training cycle. Before looking at the evidence, here is the function of each one.

See the Wolverine Stack 2026 update for the latest on how BPC-157 and TB-500 interact at the tissue level, including the 2024 prodrug finding that may change how you think about TB-500 dosing.

MOTS-c: Why the Athletes Who Train Hardest Have the Least of It

MOTS-c is written in the small separate genome your mitochondria carry, not in the DNA in the cell nucleus. Your mitochondria release it as a signal when energy runs short. It switches on AMPK, the cell's low-fuel sensor, tilts you toward burning fat during exercise, and improves how efficiently mitochondria make energy. Acute exercise raises circulating MOTS-c. The story for chronic high-load training is completely different.

A 2024 study published in Nutrients by Alser et al. measured serum MOTS-c in 75 professional endurance athletes and compared them to 30 sedentary controls. The result: professional athletes had significantly lower resting MOTS-c than the sedentary group. Sustained high-volume endurance training appears to turn baseline MOTS-c production down as an adaptation. The athletes who train the hardest are making the least of it at rest.

"Endurance training enhances skeletal muscle mitochondrial respiration by promoting MOTS-c secretion during acute exercise. Resting serum MOTS-c is lower in high-volume trained athletes compared to sedentary controls, suggesting adaptive downregulation under chronic training load."

Feng et al., Free Radical Biology and Medicine, 2025

This reframes the entire MOTS-c decision. You are not adding a performance-enhancing substance on top of what hard training already produces. You are replacing the baseline that chronic load has reduced. For a 15-hour-per-week triathlete late in a base training block, that distinction is significant. For deeper context on the mechanism and what the decline looks like across decades, see the MOTS-c deep dive.

A third human study (Nutrients 2023, PMC10573682) found MOTS-c tracked with lower-body muscle strength but not with peak VO2, which cuts against the aerobic story. The animal data on AMPK and fat burning is strong. The human performance data is thin. Treat MOTS-c as well-supported in mechanism and preliminary in outcomes.

Why BPC-157 Matters for Race Day, Not Just Injury Recovery

Gut trouble during exercise is not a fringe complaint. During prolonged aerobic effort, blood is redirected from the gut to working muscles. Starving the gut lining of blood damages it, opens gaps in the wall, and triggers nausea, cramping, and diarrhoea in a large fraction of athletes who push hard enough for long enough. The longer the race, the worse it compounds.

BPC-157's key property here is surviving the stomach. Swallowed, it gets through stomach acid and reaches the gut lining intact. In animal models from the laboratory of Predrag Sikiric, BPC-157 sped up healing of gut ulcers, protected the gut wall against damage from anti-inflammatory painkillers and from stress, and reduced the inflammatory signals coming out of intestinal tissue. A 2025 review (Sikiric et al., PMC11859134) covers the cell-protective mechanism directly. No completed human trials exist for athletic gut use. The mechanism is plausible and the animal evidence is extensive.

Most athletes using BPC-157 report the most noticeable gut benefit during training blocks with four or more sessions per week. The common protocol is oral BPC-157 at 250 to 500 mcg daily, taken in the morning or pre-workout, for 6 to 8 weeks followed by a 4-week break. The BPC-157 and TB-500 half-life guide explains clearance windows and what that means for timing around hard sessions.

TB-500 and Ipamorelin: What the Evidence Actually Shows

TB-500 (Thymosin beta-4) gets repair cells moving to where the damage is and grows new blood vessels to supply them. In animal models and a 2025 orthopaedics review (PMC12753158), it sped up tendon, ligament, and muscle repair by pulling muscle precursor cells into the injury and reworking the scaffolding those cells rebuild on. For endurance athletes the use case is overuse damage: repetitive loading at high weekly volume creates microscopic tears in tendons and connective tissue faster than the body repairs them. TB-500 addresses the repair side of that imbalance. No human RCTs exist for athletic use.

Ipamorelin prompts a growth hormone pulse 30 to 60 minutes after injection without meaningfully raising cortisol or prolactin, which is what separates it from the older compounds in its class. CJC-1295 without DAC stretches that pulse from roughly 90 minutes to six hours, matching the natural release pattern during deep sleep. The foundational human data on how the compound behaves in the body comes from Alba et al. in the Journal of Clinical Endocrinology and Metabolism (2006, PMID 16822960), showing sustained dose-dependent increases in GH and IGF-1 from CJC-1295 in healthy adults. No endurance-specific trials have been run.

The sleep dependency matters. Ipamorelin amplifies a pulse that only happens during slow-wave sleep. If your sleep architecture is disrupted by overtraining, travel, or altitude, the compound cannot do its job. Fix the sleep before adding the peptide. The peptide cycling guide covers how to structure on and off windows to prevent receptor blunting over a full training season.

Evidence tier for each compound in this stack

Every Peptide in This Stack Is Banned by WADA. Here Is What That Actually Means.

The 2026 WADA Prohibited List classifies BPC-157 under S0 (Non-Approved Substances), TB-500 under S2 (Growth Factors and Mimetics), MOTS-c under S0, and ipamorelin and CJC-1295 under S2.2 (Growth Hormone Releasing Factors). The S0 category prohibits any substance not approved for human therapeutic use by a major regulatory authority, even if it is not explicitly named. Every peptide in this stack meets that threshold. None require a positive test to trigger a violation.

Strict liability means that if the substance is found in your sample, you are responsible, regardless of how it got there or who prescribed it. The default sanction for a first violation is four years. Aggravating circumstances, including social media promotion of banned substances to other athletes, can extend or complicate the sanction.

The September 2025 USADA sanction for triathlete Anthony McCauley (usada.org, published September 17, 2025) confirmed what many guides had not warned: a triathlete using BPC-157, TB-500, CJC-1295, and ipamorelin received a four-year suspension and lost all results from June 2024 onward. McCauley's case also included promotion of these compounds on social media to followers who competed under WADA rules. USADA treated that promotion as a separate violation.

The complicating factor for 2026 is the FDA reclassification. On April 22, 2026, HHS removed approximately 14 peptides from the Category 2 restricted compounding list, restoring the prescribing pathway at licensed compounding pharmacies. BPC-157, TB-500, ipamorelin, MOTS-c, and others are now legally obtainable with a physician's prescription in the US. That change has zero effect on WADA eligibility. A legal prescription in the US does not alter your status under the WADA Prohibited List. The USADA has published a dedicated explainer on BPC-157 specifically addressing this confusion.

Which Layer of This Stack Should You Start With?

The peptides here address different bottlenecks. Which one is actually limiting you is partly inherited, and knowing that before you spend anything tells you where to start rather than running all four at once.

If your muscle is already built for endurance

The gene ACTN3 makes a structural protein found only in fast-twitch muscle fibres. A common variant cuts the instructions short, and people who inherit that version from both parents make none of the protein at all. They are over-represented among elite endurance athletes in multiple studies, because losing it pushes the muscle toward slow-twitch, endurance-leaning behaviour. The trade is lower peak power and, usually, less connective tissue damage per training hour than a power-dominant athlete accumulates. If that describes you, MOTS-c and the mitochondrial work is the higher-leverage layer, and TB-500 matters less because there is less tissue stress to repair.

If you pay a higher cardiovascular price per hour

The gene ACE makes the enzyme that constricts blood vessels and raises blood pressure, and it comes in a low-activity and a high-activity version depending on whether a chunk of DNA is present or missing. Carriers of two low-activity copies show up at higher rates in elite endurance events from marathon to rowing. Carriers of two high-activity copies lean toward power, and put more cardiovascular and metabolic strain through the same aerobic workload. That second group needs more recovery between sessions, which is why TB-500 and BPC-157 carry more weight in their stack at the same training volume.

If your oxygen delivery has a ceiling

EPOR is the docking site on your bone marrow cells that the hormone EPO uses to order more red blood cells. Rare versions that overreact produce far more red cells than normal and correspondingly more oxygen delivery, which is the mechanism behind the famous Eero Mantyranta case. Commoner low-efficiency versions do the opposite: they cap oxygen delivery in a way training only partly works around. If that is your situation, improving how efficiently your muscle uses the oxygen it does get is worth more than adding training volume, which is the argument for the mitochondrial layer.

Your 23andMe or AncestryDNA raw file already contains the two markers that call the first two of these (rs1815739 and rs4646994). Uploading it to your peptide genetics report reads both in under five minutes, along with the tendon-collagen and blood-vessel markers that speak to injury risk and BPC-157 response.

How to Structure This Stack Across a Training Season

Stacking all four compounds simultaneously across a full season is not the right approach. Each compound addresses a different phase of training stress. Layering them relative to your training calendar produces better results than running all of them continuously.

Base training: high mileage, low intensity

This is the phase for BPC-157 and TB-500. Cumulative soft tissue stress peaks during high-volume base blocks when intensity is low enough that you can push mileage. Daily oral BPC-157 at 250 to 500 mcg and twice-weekly TB-500 at 2 mg subcutaneous for 8 to 10 weeks builds the protective layer before intensity blocks accumulate additional inflammatory load.

Threshold and intensity blocks

Add ipamorelin (100 to 200 mcg subcutaneous before sleep) and MOTS-c (5 to 10 mg subcutaneous, three times per week) during intensity blocks. This is when overnight GH-driven repair and mitochondrial efficiency both matter most. The combined physiological demand on recovery systems peaks during threshold work, and these two compounds address that demand from two separate mechanisms.

Race taper and peak competition

Cycle off all compounds 4 to 6 weeks before a peak event. This allows natural hormone patterns to normalize and avoids any residual receptor blunting from continuous compound use during the taper window. For a full Ironman or A-race marathon, the taper itself is the recovery stimulus. Adding peptide load during the taper adds variables without meaningful benefit.