MOTS-c EMA vs FDA Approach: Regulatory Status, Safety, and What Patients Need to Know

Regulatory and legal status of MOTS-c [1]

What is MOTS-c?

MOTS-c ('mitochondrial open reading frame of the 12S rRNA-c') is a 16-amino-acid peptide — Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg — with a molecular weight of about 2174.6 g/mol, encoded in mitochondrial DNA and first reported in 2015 [1][11]. 'MOTS-c' is a common name rather than an official drug name, and FDA treats the free base and the acetate salt as different bulk substances [1].

Does the EMA authorize MOTS-c?

No. FDA's July 2026 review found no product containing MOTS-c authorized by the European Medicines Agency and no listing in the European or Japanese pharmacopeias [1].

Where does the FDA stand?

MOTS-c is not an FDA-approved drug and is not a component of one [1]. It appears in none of the three categories on FDA's list for state-licensed pharmacies and physicians (updated May 14, 2026) and is absent from FDA's list for outsourcing facilities (updated March 21, 2025) [4][5][6]. The interim category 1 policy, under which FDA generally does not intend to act against compounders that meet its conditions, does not cover it [4][5][6].

FDA's page on bulk substances that may present significant safety risks (content dated 04/22/2026) lists MOTS-c in the 'nominated but withdrawn' table, which holds substances previously in category 2 whose nominators withdrew them [12]. FDA's stated concerns are that it has not identified any human exposure data for drug products containing MOTS-c administered by any route, that the substance lacks important safety information, and that injectable peptides may pose immunogenicity risk from aggregation and impurities; removal from category 2 was not a finding that MOTS-c is safe [12].

In its July 2026 briefing document, FDA staff proposed that neither the free base nor the acetate be added to the pharmacy bulks list [1]. The reasons given: MOTS-c is not well characterized (inconsistent naming; no impurity, aggregate or endotoxin data), its use in compounding is unknown, there are no human safety or effectiveness data, there are no animal toxicity studies, and FDA-approved treatments exist for obesity and osteoporosis, two of the nominated uses [1]. The nominated uses were insulin resistance, obesity, osteoporosis, vascular calcification, muscle and fat metabolism and longevity, as 5 mg and 10 mg subcutaneous injections [1].

On July 23, 2026 the Pharmacy Compounding Advisory Committee voted in favor of adding MOTS-c to the bulks list, against the staff recommendation [7][8]. That vote is advice only and not binding, and MOTS-c is not on the list; adding it requires formal rulemaking [7][8].

What does the October 2026 HHS draft policy do?

HHS filed a draft enforcement-discretion policy for compounding with certain peptides on October 28, 2026 — Federal Register document 2026-22192, publication scheduled for October 30, 2026, with comments due two weeks after publication [8][9]. It names MOTS-c among six peptides (BPC-157, epitalon, KPV, MOTS-c, Semax, TB-500) and covers MOTS-c acetate given by subcutaneous or intramuscular injection [8][9].

Under the draft, HHS says it 'does not intend to take enforcement action' against a state-licensed pharmacy, federal facility or licensed physician compounding with MOTS-c if the policy's conditions are met — for example a single active ingredient, a patient-specific prescription, an FDA-registered manufacturer with a certificate of analysis, and the label statement 'This is a compounded drug product. Not for resale.' [8][9]

The draft is not an approval and does not put MOTS-c on any list. The notice says it 'does not establish any rights for any person and is not binding on HHS or the public', and HHS may revisit it, for instance if a safety signal or product quality issue arises [8]. Compounded drugs are not FDA-approved: FDA does not review their safety, effectiveness or quality before marketing [8].

Has MOTS-c ever been given to a person in a study?

FDA searched PubMed, Embase, the Cochrane library and other sources and found no clinical study of MOTS-c given to humans; the 12 papers the nominator cited were not clinical studies [1]. There is no approved dose and no human dosing study of administered MOTS-c [1].

All of the pharmacology comes from cells and rodents. In mice, injected MOTS-c reduced weight gain on a high-fat diet (about 20% lower body weight after 8 weeks at 0.5 mg/kg/day intraperitoneal) and improved insulin sensitivity and exercise performance [1][11]. In one late-life mouse study, MOTS-c was given at 15 mg/kg three times weekly from 23.5 months of age; median lifespan increased from 912 to 970 days [1]. FDA notes that the molecular targets are unknown and that no dose-response relationships were assessed [1]. An in-vitro study found MOTS-c is quickly broken down in human blood, which raises the question whether injecting it can produce active levels in people [1]. Rodent doses of 0.5 to 15 mg/kg cannot be converted into human doses [1].

The human studies that exist measured the body's own MOTS-c, not an injected product. Exercise induces endogenous MOTS-c expression in human skeletal muscle and in the circulation [2]. In a trial of 30 healthy adults randomized to endurance exercise (n=10), resistance exercise (n=10) or control (n=10), circulating MOTS-c showed only a trend to increase after endurance exercise, and plasma MOTS-c was not related to fitness [3]. A 2015 paper proposed that the m.1382A>C variant in the MOTS-c gene, which is specific to Northeast Asian populations, may help explain Japanese longevity; that is a hypothesis paper about a gene variant, not a drug trial [13].

What is known about safety?

FDA's adverse-event database searches through March 9, 2025 retrieved no MOTS-c reports [1].

FDA's stated concern for the injected form is immunogenicity — an immune reaction — from aggregation and peptide-related impurities; MOTS-c has 16 amino acids and no immunogenicity data exist [1]. There are also no pharmacokinetic data for MOTS-c in humans or in live animals; the only kinetic observation is rapid breakdown in human blood in vitro [1].

Is MOTS-c prohibited in sport?

Yes, and by name. WADA's Prohibited List lists MOTS-c in section S4.4.1, among metabolic modulators — activators of AMP-activated protein kinase — alongside AICAR [10]. It is prohibited at all times, in and out of competition, and S4.4 substances are non-Specified Substances [10]. It appears on the 2026 List, in force since January 1, 2026, and remains on the 2027 List [10][14]; FDA notes it was already on the 2024 List [1].