Sports Medicine review covers MOTS-c, SS-31 alongside BPC-157

A narrative review published April 12 in Sports Medicine (Springer) is the first paper in a major sports medicine journal to formally assess MOTS-c, SS-31 (Elamipretide), and Follistatin-344 alongside the more widely-discussed BPC-157, TB-500, and GH secretagogues — and reaches a consistent conclusion across all unapproved compounds: preclinical signals, absent human data.

What happened

Christopher Mendias and Tariq Awan reviewed twelve peptides marketed directly to patients for injury recovery and performance enhancement: AOD-9604, BPC-157, CJC-1295, Follistatin-344 (FS-344), GHK-Cu, Ipamorelin, MOTS-C, Sermorelin, SS-31 (Elamipretide), Tesamorelin, Thymosin Beta-4 (Tβ4), and TB-500.

The paper distinguishes between compounds with approved uses — tesamorelin (Egrifta) carries FDA approval for HIV-associated lipodystrophy; sermorelin has an established prescribing history in GH deficiency — and the full gray-market tier where no approved indication exists. For the unapproved tier, Mendias described to Outside Online receiving "four or five patient questions daily about peptides" at his Phoenix sports medicine practice. On BPC-157 specifically, his assessment was direct: "fairly compelling studies in small animals, but there are zero rigorous clinical trials."

MOTS-c and SS-31 appear here in a sports medicine journal context for the first time. Both are mitochondrial-derived peptides (MDPs). MOTS-c is encoded within mitochondrial 12S rRNA and has shown insulin-sensitizing and exercise-mimetic effects in rodent models; SS-31 (Elamipretide) has progressed furthest toward clinical use of any MDP, with Phase 2/3 trials in Barth syndrome and primary mitochondrial myopathy, though the FDA rejected an NDA in 2021 on efficacy grounds. The review places both in the preclinical-evidence tier and cautions against clinical use outside formal trials.

Follistatin-344 (FS-344), a myostatin inhibitor, receives its first sports medicine journal treatment as well. FS-344 has attracted interest as a lean-mass agent, but existing human evidence is limited to gene-therapy contexts. The authors flag FS-344's regulatory position as unclear relative to WADA's category for myostatin inhibitors, which include ACE-031.

Why it matters

The Sports Medicine paper builds on a January 2026 injectable peptide primer published in AJSM by USC researchers that covered BPC-157, TB-500, CJC-1295 with Ipamorelin, Tesamorelin, and GHK-Cu. The Mendias and Awan review extends that scope to six additional compounds — most notably MOTS-c, SS-31, and Follistatin-344 — that had not previously been assessed in a sports medicine journal but have gained traction in patient-facing peptide communities.

Two high-impact sports medicine journals reaching the same conclusion within four months is a different institutional signal than isolated commentary. AJSM and Sports Medicine together reach most practicing sports medicine physicians and their editorial boards; consistent findings in both publications set the conditions for formal professional-society position statements on how clinicians should counsel patients about these compounds.

For anyone tracking mitochondrial peptide research, the review represents the beginning of formal clinical scrutiny of MOTS-c and SS-31 in a sports context — a precursor to the kind of attention that generates trial registrations and funding proposals.

What to watch

• Whether AOSSM, AMSSM, or any major sports medicine organization issues a formal position statement on gray-market peptide counseling, drawing on these paired reviews as evidence
• Whether the review generates registered clinical trial proposals on ClinicalTrials.gov for MOTS-c or SS-31 in musculoskeletal indications
• Whether Follistatin-344 attracts WADA enforcement attention comparable to that given to ACE-031, which was added to the Prohibited List in 2013
• The paper's citation trajectory — if it is cited in the July 2026 PCAC committee materials as context for the clinical-evidence gap, it would represent a direct regulatory impact

Sources

• PubMed — Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance (PMID 41966639)
• Medscape — Gray Market Peptides: So Much Hype, So Little Data
• Outside Online — With the Rise of Ozempic, Athletes Are Now Exploring Alternative Performance Peptides