MOTS-C Documentation Guide: Identity, Related Mitochondrial Peptides, and How to Evaluate the Certificate

A practical documentation, verification, and research-context guide for research buyers.

This article is a documentation guide. It covers chemical identity, what a MOTS-C Certificate of Analysis (COA) should contain, how oxidation-sensitive sequences affect the paperwork you should demand, where the compound sits in the research literature, and how related mitochondrial research peptides such as SS-31 are documented. It does not make claims about biological activity, experimental outcomes, or dosing, and it does not recommend any use. A supplier is the wrong source for those questions; the published literature and your own experimental design are the right ones.

What MOTS-C Is, Chemically

MOTS-C (Mitochondrial Open Reading Frame of the 12S rRNA type-c) is a 16-amino-acid peptide encoded within the mitochondrial genome. Its sequence is Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg (one-letter: MRWQEMGYIFYPRKLR). Key registry data include:

• CAS Registry Number: 1627580-64-6
• Molecular formula: C₁₀₁H₁₅₂N₂₈O₂₂S₂
• Molecular weight (free peptide): 2174.6 g/mol
• UniProt: A0A0C5B5G6 (MOTSC_HUMAN), Swiss-Prot reviewed

For the full sequence-level discussion, oxidation chemistry, salt-form considerations, and a MOTS-C-specific COA checklist, see our detailed identity guide: What Is MOTS-C? Sequence, CAS, and What Its COA Should Say.

Where MOTS-C Appears in the Research Literature

For readers deciding whether MOTS-C fits their work, it helps to know where the compound sits in the published literature. MOTS-C is one of a small group of mitochondrial-derived peptides, and in peer-reviewed research it is studied primarily within mitochondrial biology and cellular energy metabolism, and it appears in exercise-physiology and aging research as an endogenous, exercise-responsive peptide. This is a map of the research field, not a statement about results: the primary peer-reviewed literature and your own experimental design are the authoritative sources for any question about activity or outcomes.

USA Made Peps supplies MOTS-C strictly as a research chemical. We make no representation about biological activity, efficacy, dosing, or suitability for any use in living systems, and nothing here should be read as encouraging such use. See the Research Use Only notice at the end of this article.

Why the Sequence Matters for the Certificate

Three of MOTS-C’s sixteen residues are oxidation-sensitive: methionine at positions 1 and 6, and tryptophan at position 3. Methionine oxidation adds approximately 16 Da per site. A mass spectrum that shows only the parent mass (≈2174.6) is useful; a spectrum that also shows the relative intensity of the +16 and +32 species tells you far more about the actual material in the vial.

Because these impurities are predictable from the sequence itself, a thorough COA can be checked against them rather than simply accepted. Purity by HPLC reflects the area of the main peak relative to all peaks; an oxidised species that separates cleanly appears as an impurity and correctly lowers the reported purity. That is the measurement system working as designed.

Related Mitochondrial Research Peptides: SS-31

Researchers working with mitochondrial systems frequently encounter more than one compound. SS-31 (also known as elamipretide, MTP-131, or Bendavia) is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂. It is documented under CAS 736992-21-5 and has a molecular weight of approximately 639.8 g/mol. Its structure (alternating aromatic and cationic residues, D-enantiomer at the N-terminus, C-terminal amide) is load-bearing for identity confirmation; a certificate missing any of those features describes a different molecule.

From a documentation standpoint, the same rules apply: lot-specific third-party COA, mass-spectrometry identity confirmation, HPLC purity with chromatogram, and endotoxin data when relevant. The two compounds are chemically distinct and should never be treated as interchangeable on a certificate or in a literature search.

See our companion guide: What Is SS-31? A Plain-English Look at a Mitochondria-Targeted Research Peptide.

How to Evaluate a MOTS-C Certificate of Analysis

A Certificate of Analysis is only as useful as its specificity to the material you actually received. Use this short checklist:

• Lot number on the COA matches the lot number printed on the vial.
• Identity confirmed by mass spectrometry, with observed mass consistent with 2174.6 (free peptide) or a clearly stated salt form.
• Purity reported by HPLC (or UPLC), ideally with the chromatogram included rather than a summary percentage alone.
• Net peptide content reported separately, or salt form explicitly stated so the difference is understood.
• Endotoxin result present when the experimental design is sensitive to it.
• Testing laboratory named and independent of the seller.

For a line-by-line walkthrough of every section that appears on a typical peptide COA, use our guide: How to Read a Certificate of Analysis (COA). Additional background on what the purity number actually measures is available in What Is Peptide Purity, and How Is It Measured?.

Verify Any Lot Before or After You Order

Every lot published by USA Made Peps is listed in a public register with purity, test date, testing laboratory, and downloadable purity (and, where available, endotoxin) certificates. You can look up a lot number without purchasing. This removes the “request a COA and wait” step that still exists at many suppliers.

Use the lookup tool here: usamadepeps.com/verify. Enter the lot number printed on the vial (format UMP-XXXXXXX or DPS-XXXXXXX). The system returns the product name, purity, test date, lab, and the PDFs.

If you prefer to test the material yourself, our Don’t Trust Us, Test Us program replaces any vial you send to an independent laboratory for analysis, pass or fail. Details are at usamadepeps.com/test-us.

Storage Notes Specific to This Sequence

General lyophilized-peptide storage guidance applies: cold, dry, sealed, protected from light, and allow the vial to reach room temperature before opening to avoid condensation. Because MOTS-C contains tryptophan, light protection is more consequential than it is for sequences that lack it. Compendial storage definitions (freezer −25 °C to −10 °C, refrigerator 2 °C to 8 °C, etc.) should be used rather than vague terms such as “store cold.”

See Shelf Life and Stability of Lyophilized Research Peptides and How to Store Research Peptides for the practical details.

MOTS-C at USA Made Peps

Our MOTS-C is supplied as lyophilized powder, independently third-party tested, and accompanied by a lot-specific COA that is published before the material ships. Current product details and available sizes are on the MOTS-C product page.

All processing steps that determine purity, identity, and integrity occur in the United States. Every lot we have shipped has a certificate in the public register.

Related Documentation

• What Is MOTS-C? Sequence, CAS, and What Its COA Should Say
• What Is SS-31?
• How to Read a Certificate of Analysis
• Verify a Lot (public COA register)
• What Is Peptide Purity?
• Endotoxin Testing Explained
• How to Vet a Research Peptide Supplier
• Research Peptide Education Blog (all guides)

References

Sources are limited to curated sequence and chemical registries and identity data. Nothing here is cited for biological activity, and no supplier catalogue is used as a source. Each was checked on 18 August 2026.

1. UniProt Knowledgebase, entry A0A0C5B5G6 (MOTSC_HUMAN), Swiss-Prot reviewed. Recommended name “Mitochondrial-derived peptide MOTS-c”; sequence MRWQEMGYIFYPRKLR, length 16 residues.
2. PubChem Compound, CID 146675088 (MOTS-c): molecular formula C101H152N28O22S2, molecular weight 2174.6 g/mol (free peptide). Verified against the live PubChem record on 18 August 2026.
3. CAS Registry Number 1627580-64-6, MOTS-c, listed as the identity registry number for this sequence. No link is given because CAS Common Chemistry carries no free public entry we could confirm, and we do not link catalogue pages as sources.

Research Use Only Disclaimer

Related reading: how to read a Tesamorelin COA, and what >98% purity actually means.

All products sold by USA Made Peps are designated Research Use Only (RUO). They are intended exclusively for in-vitro laboratory research and scientific investigation. They are not drugs, foods, dietary supplements, cosmetics, or medical devices. They have not been evaluated or approved by the U.S. Food and Drug Administration for safety or efficacy in humans or animals. They are not intended for human or veterinary use, consumption, administration, or any form of in-vivo application. This content is provided for scientific and educational documentation purposes only. By accessing this material you confirm that you understand the RUO designation and accept full responsibility for lawful use in your jurisdiction.

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