MOTS-C

What MOTS-c Is

MOTS-c (Mitochondrial Open Reading-frame of the Twelve S rRNA-c) is an endogenous 16-amino-acid peptide encoded within the human mitochondrial 12S rRNA gene (MT-RNR1). Unlike most research peptides — which are synthetic novel sequences — MOTS-c is a member of the small class of mitochondrial-derived peptides (MDPs), alongside humanin and the SHLPs. It was characterised by Cohen and colleagues (Lee et al., Cell Metabolism 2015) as the founding member of the MDP class.

The 2026 Mechanism Surge

A wave of 2026 peer-reviewed research has identified previously unrecognised MOTS-c mechanisms, expanding the mitochondrial-derived-peptide pharmacology beyond AMPK signalling alone:

• Lysosomal membrane protection — Shi et al., Autophagy 2026 (PMID 42153537). Newly identified MOTS-c role with relevance to autophagy and tissue-transplantation survival research models.
• Nrf2 antioxidant defence (engineered variant) — Zhang et al., Redox Biol 2026 (PMID 42142418). LAT1-mediated delivery of an engineered R13A-MOTS-c variant attenuates radiation-induced lung injury via Nrf2 pathway. Note: Artemis supplies wild-type MOTS-c, not R13A-MOTS-c.
• Oxeiptosis inhibition — Li et al., Life Sci 2026 (PMID 42128272). MOTS-c attenuates hyperoxia-induced neonatal cardiac injury via maintenance of KEAP1-PGAM5 interaction.
• Spermatogenesis preservation via SLC7A11 — Liu et al., Free Radic Biol Med 2026 (PMID 41933740). MOTS-c suppresses ferroptosis in spermatogenesis under oxidative stress.
• Class-level retrograde-signalling review — Harding et al., Cell Commun Signal 2026 (PMID 41937181) — consolidates mitochondrial-DNA-derived peptide signalling as a class.

Emerging Clinical Biomarker Evidence (Observational)

The 2026 clinical literature is converging on serum MOTS-c as a candidate observational biomarker. Important caveat: these are correlation studies, not therapeutic-endpoint studies — they establish that MOTS-c levels track disease state, not that exogenous MOTS-c modifies disease outcome.

• Myocardial ischaemia–reperfusion injury (Peng et al., Biomedicines 2026, PMID 42072458)
• Peritoneal dialysis arterial stiffness (Musolino et al., Int Urol Nephrol 2026, PMID 42126770)
• Polycystic ovary syndrome (Filibeli et al., Arch Endocrinol Metab 2026, PMID 41945630)

How Artemis Labs Sources and Verifies MOTS-c

Each lot is supplied as a sterile lyophilised peptide powder, analytically verified by reverse-phase HPLC to ≥99% peptide purity, with identity confirmed by mass spectrometry and endotoxin tested ≤0.5 EU/mg by LAL assay. The compound shipped is wild-type human MOTS-c (sequence MRWQEMGYIFYPRKLR, molecular weight ~2,174.7 g/mol, molecular formula C₁₀₂H₁₅₈N₂₈O₂₂S₂). Engineered variants such as R13A-MOTS-c are separate research molecules and not what Artemis supplies.

Honest Limitations of the MOTS-c Evidence Base

The MOTS-c literature is rich on mechanism and observational biomarker work but thin on randomised controlled trial evidence in humans. The single published interventional human study (CB4211 Phase 1a/1b, 20 obese participants, 28 days) is small and short-duration. Several high-impact 2026 mechanism papers test engineered variants (e.g. R13A-MOTS-c) — Artemis supplies wild-type only, and engineered-variant findings do not directly transfer. The 2026 mechanism surge introduces multiple new pathways (lysosomal protection, oxeiptosis, ferroptosis, SLC7A11) each as first-or-second-report findings; independent replication is pending. Endogenous-peptide status does not equal supraphysiological-exposure safety — the relevant pharmacology question is not answered in the 2024–2026 literature.

Class Positioning

MOTS-c is mechanistically complementary to SS-31 (elamipretide), which is a synthetic tetrapeptide that targets the mitochondrion from outside via cardiolipin binding. MOTS-c originates inside the mitochondrion and signals outward to the nucleus. The two are paired in research models to distinguish inner-membrane-stabilisation biology (SS-31) from retrograde-signalling biology (MOTS-c). Related catalogue compounds include GHK-Cu (gene-expression modulator), Semax (neuropeptide), and the broader CJC-1295 / Ipamorelin GH-axis pair.

Regulatory and Compliance Framing

MOTS-c is an endogenous human peptide — encoded within human mitochondrial DNA and naturally expressed across all human cells. Despite this endogenous origin, no FDA-approved human therapeutic indication exists for MOTS-c. The compound was not placed on FDA 503A Category 2 during the 2023–2024 peptide review process. MOTS-c is not currently on the WADA Prohibited List as of the 2026 update; given growing exercise-physiology and metabolism literature, future WADA list changes warrant monitoring. Research-use-only framing applies to all commercial supply. These statements have not been evaluated by the FDA. Not for human consumption, therapeutic use, or veterinary use.

Science & Research

Mechanism of Action — Mitochondrial-to-Nuclear Retrograde Signalling

MOTS-c is a 16-residue peptide (sequence MRWQEMGYIFYPRKLR; Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg) encoded within the human 12S mitochondrial ribosomal RNA gene (MT-RNR1). It was first characterised by Cohen and colleagues (Lee et al. 2015, Cell Metabolism) and is the founding member of a class of mitochondrial-derived peptides (MDPs), alongside humanin and the SHLPs (SHLP1–6).

Under basal conditions MOTS-c is primarily mitochondrial. Under metabolic stress (glucose restriction, oxidative load, exercise), MOTS-c is released and translocates to the nucleus, where it modulates expression of nuclear stress-response genes via AMPK-pathway activation. This mitochondrial-to-nuclear retrograde signalling pathway is reviewed as a class-level mechanism for MDPs (Harding et al. 2026, Cell Commun Signal, PMID 41937181).

2024–2026 Mechanism Updates

• Lysosomal membrane protection — Shi et al. 2026 (PMID 42153537): MOTS-c ameliorates lysosomal membrane permeability and improves survival in soft tissue transplantation research models.
• Engineered variant + targeted delivery — Zhang et al. 2026 (PMID 42142418): LAT1-mediated delivery of an engineered R13A-MOTS-c variant attenuates radiation-induced lung injury via Nrf2 activation. Note: R13A-MOTS-c is an engineered variant; Artemis supplies wild-type MOTS-c.
• Oxeiptosis inhibition in cardiac tissue — Li et al. 2026 (PMID 42128272): MOTS-c attenuates hyperoxia-induced neonatal cardiac injury by inhibiting oxeiptosis — a recently characterised oxygen-radical-driven cell-death pathway — via maintenance of the KEAP1-PGAM5 interaction.
• Reproductive-axis activity (ferroptosis suppression) — Liu et al. 2026 (PMID 41933740): MOTS-c targets SLC7A11 (cystine/glutamate antiporter) to preserve spermatogenesis under oxidative stress by suppressing ferroptosis.
• Adrenal-cortex metabolic priming — Blatkiewicz et al. 2026 (PMID 41811086): MOTS-c primes adrenal cortex metabolism without directly driving steroidogenesis — distinguishes metabolic priming from hormone-secretion stimulation.

Emerging Clinical Biomarker Evidence (Observational)

2026 clinical correlation studies demonstrate that serum MOTS-c levels track disease severity across multiple human populations. These are correlation studies, not therapeutic-endpoint studies — biomarker work, not treatment validation.

• Myocardial ischaemia–reperfusion injury — Peng et al., Biomedicines 2026, PMID 42072458.
• Peritoneal-dialysis arterial stiffness — Musolino et al., Int Urol Nephrol 2026, PMID 42126770.
• Polycystic ovary syndrome — Filibeli et al., Arch Endocrinol Metab 2026, PMID 41945630.

Cross-Cutting Peptide-Therapy Review (2026)

Mendias and Awan, Sports Med 2026 (PMID 41966639): approved and unapproved peptide therapies for musculoskeletal injuries and athletic performance — MOTS-c covered in the mitochondrial-derived peptide section as an investigational research compound.

Entity Disambiguation

Quality and Specifications

• Sequence: MRWQEMGYIFYPRKLR (16 amino acids)
• Molecular formula: C₁₀₂H₁₅₈N₂₈O₂₂S₂
• Molecular weight: ~2,174.7 g/mol
• Gene origin: Human MT-RNR1 (12S mitochondrial rRNA gene)
• Purity: ≥99% by reverse-phase HPLC; identity confirmed by mass spectrometry
• Endotoxin: ≤0.5 EU/mg (lot-specific LAL assay)
• Form: Lyophilised white powder, 40 mg/vial
• Storage: Lyophilised at −20°C desiccated, protected from light; reconstituted at 2–8°C in bacteriostatic water; use within research-validated stability window

Counter-Evidence and Honest Limitations

• Observational biomarker work is not therapeutic validation. The 2026 clinical correlations (Peng, Musolino, Filibeli) show MOTS-c level tracks disease state — not that exogenous MOTS-c modifies disease outcome.
• Single small human interventional trial. CB4211 Phase 1a/1b (20 participants, 28 days) is the only published interventional human study. Sample size, duration, and endpoint scope are limited.
• Engineered-variant vs wild-type confound. Multiple 2026 mechanism papers test R13A-MOTS-c (Zhang 2026 PMID 42142418) — wild-type findings may not transfer.
• 2026 mechanism surge is uncorroborated. Lysosomal protection, oxeiptosis inhibition, and SLC7A11/ferroptosis suppression are each first-or-second-report findings; independent replication pending.
• Endogenous status ≠ supraphysiological-exposure safety. Natural production does not validate exogenous research-protocol exposure levels.
• CAS-number inconsistency across vendors. Rely on sequence and HRMS/MS confirmation rather than CAS lookup for chemical identity verification.

References (10 PubMed-Verified)

1. Shi J. (2026) Autophagy. PMID 42153537
2. Zhang YL. (2026) Redox Biol. PMID 42142418
3. Li SH. (2026) Life Sci. PMID 42128272
4. Liu S. (2026) Free Radic Biol Med. PMID 41933740
5. Blatkiewicz M. (2026) Folia Histochem Cytobiol. PMID 41811086
6. Musolino M. (2026) Int Urol Nephrol. PMID 42126770
7. Peng L. (2026) Biomedicines. PMID 42072458
8. Filibeli BE. (2026) Arch Endocrinol Metab. PMID 41945630
9. Harding E. (2026) Cell Commun Signal. PMID 41937181
10. Mendias CL, Awan TM. (2026) Sports Med. PMID 41966639

Research Stacks

Stacking rationale below is mechanistic only. No dosing, frequency, duration, or protocol guidance is provided. Researchers design protocols against their own institutional review, not against vendor copy.

MOTS-c × SS-31 (Elamipretide)

Mitochondrial-derived peptide × synthetic mitochondria-targeted tetrapeptide. Mechanistically complementary: MOTS-c originates inside the mitochondrion and signals outward to the nucleus via AMPK retrograde signalling; SS-31 targets the mitochondrion from outside, binding cardiolipin to stabilise inner-membrane integrity. Paired in research models to distinguish retrograde-signalling biology from membrane-stabilisation biology.

MOTS-c × GHK-Cu

Mitochondrial-derived peptide × copper-tripeptide gene-expression modulator. MOTS-c modulates nuclear stress-response gene transcription via AMPK; GHK-Cu has independent broad gene-expression effects including mitochondrial biogenesis markers. The combined ‘Longevity Quartet’ research framing (MOTS-c + GHK-Cu + SS-31 + Semax) appears in multi-compound longevity research design.

MOTS-c × CJC-1295 / Ipamorelin

Mitochondrial retrograde signalling × GH-axis stimulation. Studied together for downstream metabolic effects of GH/IGF-1 signalling layered onto MOTS-c-driven AMPK-pathway activation. Cross-pathway research design.

MOTS-c × 5-Amino-1MQ

Mitochondrial-derived peptide × NNMT inhibitor (small molecule). Both engage NAD⁺-axis biology from different molecular entry points — MOTS-c via mitochondrial-to-nuclear retrograde signalling, 5-Amino-1MQ via NNMT inhibition preserving the nicotinamide salvage substrate pool. Useful research-model pairing to dissect cofactor-pool effects from peptide-signalling effects.

Related Compounds in Catalogue

For mitochondrial-axis research see SS-31, 5-Amino-1MQ. For longevity-quartet research frame see GHK-Cu and Semax. For GH-axis cross-research see CJC-1295 and Ipamorelin.