Sports Medicine flags safety data gaps in 12 unapproved peptides
A Sports Medicine review of 12 unapproved peptides — including MOTS-c, SS-31, and sermorelin — warns that human safety data are scarce despite promising animal evidence.
May 11, 2026 · 3 min read
A narrative review published April 12, 2026 in Sports Medicine — the flagship Springer journal for sports science — assessed the evidence behind twelve unapproved peptides in active use among athletes and fitness patients. The paper is notable not only for its scope but for explicitly covering mitochondrial compounds like MOTS-c and SS-31 alongside the more commonly discussed healing peptides, and for mapping each compound's status under World Anti-Doping Agency rules.
What happened
Christopher L. Mendias and Tariq M. Awan, the paper's authors, set out to give sports medicine clinicians a documented framework for advising patients about peptides they are already using. The review covers twelve compounds: AOD-9604, BPC-157, CJC-1295, follistatin-344 (FS-344), GHK-Cu, ipamorelin, MOTS-C, sermorelin, SS-31 (elamipretide), tesamorelin, thymosin beta-4 (Tβ4 / TB-500's active component), and TB-500.
The central finding is consistent across nearly all twelve: preclinical animal-model evidence shows favorable effects on tissue repair, metabolic function, or hormonal signaling, but controlled human safety data are largely absent. The authors conclude that there is "potential for serious harm to patients" if these compounds are used without a formal evidence base, and recommend against clinical use outside registered trials.
On WADA status, the review provides a useful roadmap: most of the compounds on the list — including BPC-157, TB-500, CJC-1295, ipamorelin, and MOTS-C — are prohibited in competitive sport. GHK-Cu and SS-31 are among the handful not currently on the banned list, which the authors flag as a practical distinction for sports medicine providers.
The paper was accepted March 24, 2026 and published online April 12. Outside Online subsequently covered the review in late April under the headline that new research is telling athletes they shouldn't use these peptides.
Why it matters
The Sports Medicine review follows the American Journal of Sports Medicine's January 2026 primer by Mayfield et al., which covered five compounds. Together the two papers represent a rapidly expanding mainstream sports medicine literature taking the subject seriously rather than dismissing it.
What distinguishes the Mendias-Awan paper is its coverage of compounds with mitochondrial and metabolic mechanisms — MOTS-c, SS-31, and sermorelin — that didn't appear in the AJSM piece. MOTS-c, a mitochondrial-derived peptide, has generated significant research interest for its effects on AMPK signaling and metabolic adaptation, but like most compounds in the review, has zero published human safety trials. SS-31 (elamipretide) is the exception: it has progressed through Phase I, II, and III trials for heart failure indications, giving it a comparatively robust safety record.
A peer-reviewed assessment in a high-impact sports journal matters for a specific practical reason: physicians who read it will be better equipped to counsel patients who are already using these compounds. That conversation has value regardless of whether it leads to clinical adoption, and it sets an evidence baseline at a moment when the regulatory environment for some of these peptides may be shifting.
What to watch
- Whether the AJSM and Sports Medicine reviews together catalyze trial registration activity on ClinicalTrials.gov for any covered compounds
- WADA's scheduled 2027 review of the prohibited substance list, where SS-31 and GHK-Cu status could change
- Additional journal coverage beyond sports medicine — orthopedics (JBJS, CORR) and sports pharmacology are the most likely next venues
- Any editorial or position-statement response from major sports medicine societies (AOSSM, AMSSM)
Sources
Sources
- Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance — Sports Medicine (Springer)
- PubMed — PMID 41966639
- With the Rise of Ozempic, Athletes Are Now Exploring Alternative Performance Peptides. But New Research Says They Shouldn't. — Outside Online