MOTS-c · Research brief

MOTS-c Supplier: Sourcing, Testing and Bulk Pricing

Real Peptides Research TeamEditorial

Updated September 8, 20269 min read

42 WORDS

Short answer

MOTS-c carries two methionine residues and one tryptophan, three of the most oxidation-prone amino acids in peptide chemistry. That single structural fact explains more about why one vial behaves consistently in an assay and another doesn't than any product page ever will.

Key takeaways

MOTS-c is a 16-amino-acid mitochondrial-derived peptide, sequence MRWQEMGYIFYPRKLR, with an average mass near 2174 Da, first described in Cell Metabolism in 2015.
Two methionines and one tryptophan make this sequence unusually oxidation-sensitive, so cold chain and handling matter more than they would for a rugged peptide.
Net peptide content, not HPLC purity, determines how much MOTS-c is actually in the vial, and TFA-salt peptides commonly land in the 70 to 85% range.
A batch-specific COA that names the lot number on your vial is the minimum standard for any mots-c supplier, and a +16 Da satellite peak on mass spec signals methionine oxidation.
Bulk pricing reflects synthesis scale, purity specification, analytical depth and packaging, which is why comparing a single number across vendors tells you almost nothing.
The choice between an overseas and a domestic mots-c supplier is a trade between unit price and the speed at which a failed batch can be identified, re-tested and replaced.

We synthesise and test research peptides in small batches, and we've reviewed more third-party certificates of analysis than we care to count. The distance between a competent mots-c supplier and a careless one shows up in the analytics, never in the marketing copy.

How do you evaluate a MOTS-c supplier?

A credible mots-c supplier issues a batch-specific certificate of analysis showing RP-HPLC purity, mass spectrometry identity for the 16-amino-acid sequence at roughly 2174 Da, and stated net peptide content. Research-use-only labelling, lot traceability and cold-chain packaging are baseline, not premium extras. Material sold without batch-level testing should be treated as unverified.

Purity percentage is the figure everyone quotes and the figure that misleads most often. A vial can read 99% pure by HPLC and still deliver less peptide than the label weight implies, because gross vial weight includes counterion salt and residual water. What follows covers what this molecule demands from synthesis, how to read a COA line by line, and what actually sets bulk pricing.

The molecule sets the sourcing bar

MOTS-c (mitochondrial open reading frame of the 12S rRNA type-c) is a 16-amino-acid mitochondrial-derived peptide with the sequence MRWQEMGYIFYPRKLR and an average molecular weight close to 2174 Da. It was described by Lee and colleagues in Cell Metabolism in 2015, work from Pinchas Cohen's group at the USC Leonard Davis School of Gerontology. Research suggests it acts through the folate-methionine cycle, where accumulating AICAR activates AMPK (AMP-activated protein kinase), the cellular energy sensor that shifts metabolism toward glucose uptake and fatty acid oxidation. A later report in Nature Communications by Reynolds and colleagues in 2021 characterised MOTS-c as exercise-responsive in skeletal muscle. None of this is settled clinical science, and no MOTS-c product is an FDA-approved drug.

Here is where the chemistry becomes a sourcing problem. Methionine at positions 1 and 6 oxidises readily to methionine sulfoxide, adding 16 Da per residue. The tryptophan at position 3 is light-sensitive and carries its own oxidative liability. A sequence like this punishes carelessness at every stage: cleavage, purification, lyophilisation, fill and transit. Rugged sequences forgive a warm week in a courier depot. This one may not.

Our team screens incoming synthesis batches with that specific vulnerability in mind. A mots-c supplier that has never thought about oxidation control is a mots-c supplier whose purity figure describes the day of manufacture and says very little about the vial in your freezer.

Reading a certificate of analysis line by line

A certificate of analysis is only useful if it names the lot number printed on your vial. Generic, undated COAs recycled across batches are the most common documentation failure we see when researchers forward us paperwork from another mots-c supplier for a second opinion.

Four lines carry the weight:

RP-HPLC purity. Reverse-phase high performance liquid chromatography, typically monitored at 214 or 220 nm, reports purity as a percentage of total peak area. Research-grade material is commonly specified at 98% or higher. Ask which wavelength and which gradient were used, because both change the number that gets printed.

Mass spectrometry identity. ESI-MS or MALDI-TOF should return an observed mass consistent with roughly 2174 Da for the intact sequence. Read the satellite peaks, not just the headline mass. A +16 Da or +32 Da shoulder indicates oxidised methionine, and oxidised MOTS-c is chemically a different molecule.

Net peptide content. This is the line most buyers skip. Peptides purified by RP-HPLC are usually isolated as trifluoroacetate salts, so gross vial weight includes TFA counterion, bound water and residual salts. Net peptide content for TFA-salt peptides commonly falls somewhere in the 70 to 85% range, determined by amino acid analysis or nitrogen determination.

Moisture and endotoxin. Karl Fischer titration for residual water, and LAL testing where the research application requires it.

That third line is where cost comparisons quietly break. Two vials both labelled 10 mg can differ by a fifth in actual peptide delivered. Normalise price per milligram of net peptide before concluding any mots-c supplier is the cheaper option.

Domestic synthesis, overseas sourcing, and what bulk pricing reflects

Most storefronts selling MOTS-c are not manufacturers. Bulk crude peptide moves through a relatively small number of large contract synthesis houses, and many websites are resellers repackaging that material under their own branding. Neither model is automatically wrong. Not knowing which one you are buying from is.

Two questions separate a mots c manufacturer from a mots c vendor: do you synthesise in-house or purchase crude, and who ran the analytics on this specific lot, your laboratory or the upstream supplier? A mots-c supplier that answers both plainly is telling you something real about traceability.

Overseas sourcing, and a China supplier is the comparison researchers raise most often, competes primarily on per-milligram price. The trade-offs are structural rather than moral: longer transit, more opportunity for temperature excursion, customs holds on research chemicals, and a re-test cycle measured in weeks when a batch disappoints. A domestic mots-c supplier shortens the cold chain and makes lot traceability, re-analysis and replacement practical on a research timeline.

Bulk pricing becomes legible once you know what it pays for. Per-milligram cost falls as synthesis scale rises, which is the entire reason quantity tiers exist. It rises with a tighter purity specification, extra analytics such as endotoxin and residual solvent testing, controlled lyophilisation and fill, and validated cold-chain packaging. Published mots-c wholesale price varies widely across the market, so treat every quote as a bundle of specifications rather than a single number. Our own approach at Real Peptides is small-batch synthesis with exact amino-acid sequencing and a batch-specific certificate of analysis on every lot.

Sourcing models compared

The table below maps the four ways research laboratories typically obtain MOTS-c and what each model realistically delivers on documentation, timing and price. Use it to work out which mots-c supplier model matches your tolerance for variability.

Sourcing model	Lead time and cold chain	Documentation typically provided	Per-mg price pattern	Bottom line
Overseas contract manufacturer, direct bulk	Longest transit, most exposure to temperature excursion and customs holds	Manufacturer-issued COA, often not lot-matched to the vial you receive	Lowest headline price, especially at large minimum order quantities	Workable if you have in-house analytical capability to verify every incoming lot yourself
Domestic reseller repackaging imported crude	Fast final-mile delivery, but the cold chain upstream is invisible to you	Upstream COA passed through, sometimes reformatted, rarely re-tested	Mid-range, with margin added over the imported crude price	Acceptable when the reseller discloses the origin and the testing chain honestly
Domestic small-batch supplier with in-house QC	Shortest cold chain, fastest re-test and replacement cycle	Batch-specific COA with HPLC, mass spec identity and net peptide content	Higher per mg at small volumes, narrowing as quantity tiers rise	The most defensible option when reproducibility across experiments matters more than unit price
Open marketplace or grey listing	Unpredictable packaging, frequently ambient shipping	Often none, or an image of a COA with no lot reference	Cheapest and most variable	Treat as unverified material; a mots-c supplier that cannot produce lot-matched paperwork is not a supplier, it is a listing

What If: MOTS-c Sourcing Scenarios

What if my vial arrived warm or the cold pack had melted?

Quarantine the lot, photograph the packaging and contact the supplier before opening anything. Lyophilised peptide is more tolerant of brief ambient exposure than reconstituted solution, but tolerance is not immunity, and oxidation of the methionine residues is invisible to the eye. A supplier with real QC will either re-test a retained sample from the same lot or replace the shipment. One that shrugs has told you what its documentation is worth.

What if the COA does not match the lot number on my vial?

Treat the material as uncharacterised until the mots-c supplier produces lot-matched paperwork. A COA belongs to a specific synthesis batch, and a document from a different lot describes a different set of impurities, a different oxidation profile and a different net peptide content. This is the most frequent problem we are asked to review, and it is almost always a resale chain where nobody re-tested the repackaged material.

What if an overseas quote is half what domestic laboratories charge?

Price the two options per milligram of net peptide, then add the cost of verifying the cheaper lot yourself. An overseas mots-c supplier may genuinely be cheaper at the crude level because synthesis scale is larger. The difference narrows quickly once you factor in independent HPLC and mass spec verification, customs risk, and the weeks lost if a batch fails and has to be reordered.

What if my study design involves animal models?

Route the protocol through your institutional animal care and use committee before ordering anything, and talk to your veterinarian about species-appropriate handling and welfare requirements. Research-use-only material is supplied for laboratory investigation and is not sold or described for human or veterinary consumption. This article is educational information about sourcing and analytics, and it is not administration, dosing or protocol guidance.

The uncomfortable truth about purity claims

Let's be direct about this: a 99% purity claim with no lot number, no chromatogram and no net peptide figure is a marketing number, not a measurement. Purity by HPLC area is a ratio, and it says nothing about how much peptide is in the vial, how much counterion is riding along, or whether the methionines oxidised in transit. The industry leans on that ambiguity constantly. Any mots-c supplier can print 99%. Far fewer will send you the chromatogram, the mass spec trace and the amino acid analysis that make the number mean something.

Choosing a mots-c supplier is less a purchasing decision than a reproducibility decision, because every downstream result you generate inherits whatever was actually in the vial. The researchers who get clean, comparable data across six months are rarely the ones who found the lowest price. They are the ones who standardised on one lot-traceable source, kept the retained COAs, and normalised their calculations to net peptide rather than label weight. That habit costs nothing to adopt and quietly determines whether your third experiment agrees with your first.

References

Peer-reviewed sources on MOTS-c indexed in PubMed, listed for research context. Real Peptides supplies MOTS-c for laboratory research use only.

MOTS-c improves intrinsic muscle mitochondrial bioenergetic health and efficiency in a PGC-1α/AMPK-dependent manner. Free radical biology & medicine, 2026. PMID 41520850. doi:10.1016/j.freeradbiomed.2026.01.002
Humanin and MOTS-c Attenuate Atrial Fibrillation by Suppressing Fibrosis and Mitochondrial Dysfunction. Biomedicines, 2026. PMID 42193373. doi:10.3390/biomedicines14051048
MOTS-c, a mitochondrial-derived peptide, ameliorates lysosomal membrane permeability and improves survival of soft tissue transplantation. Autophagy, 2026. PMID 42153537. doi:10.1080/15548627.2026.2677180
Mitochondrial-derived peptide MOTS-c targets SLC7A11 to preserve spermatogenesis by suppressing ferroptosis. Free radical biology & medicine, 2026. PMID 41933740. doi:10.1016/j.freeradbiomed.2026.03.074
MOTS-c attenuates cardiac dysfunction following high altitude exposure by promoting mitophagy. Free radical biology & medicine, 2026. PMID 41654147. doi:10.1016/j.freeradbiomed.2026.01.064
Mitochondrial-encoded peptide MOTS-c prevents pancreatic islet cell senescence to delay diabetes. Experimental & molecular medicine, 2025. PMID 40855115. doi:10.1038/s12276-025-01521-1
MOTS-c attenuates mitochondrial dysfunction induces pyroptosis and cartilage degradation in osteoarthritis via an Nrf2-Dependent Mechanism. Free radical biology & medicine, 2025. PMID 41043625. doi:10.1016/j.freeradbiomed.2025.09.056
MOTS-c Promotes Glycolysis via AMPK-HIF-1α-PFKFB3 Pathway to Ameliorate Cardiopulmonary Bypass-induced Lung Injury. American journal of respiratory cell and molecular biology, 2025. PMID 40035775. doi:10.1165/rcmb.2024-0533OC

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Questions

Ask for a batch-specific certificate of analysis that names the exact lot number on your vial, including RP-HPLC purity with the detection wavelength stated, mass spectrometry identity consistent with roughly 2174 Da, and net peptide content. A legitimate mots-c supplier will also tell you plainly whether it synthesises in-house or resells imported crude. If the paperwork is generic, undated, or shown only as an image without a lot reference, treat the material as unverified.

MOTS-c is a 16-amino-acid mitochondrial-derived peptide encoded within the mitochondrial 12S rRNA gene, with the sequence MRWQEMGYIFYPRKLR and an average molecular weight near 2174 Da. Research published in Cell Metabolism in 2015 by Lee and colleagues suggests it influences the folate-methionine cycle, leading to AICAR accumulation and activation of AMPK, the enzyme that shifts cells toward glucose uptake and fat oxidation. The mechanism remains an active research area rather than settled clinical science.

MOTS-c is sold as research-use-only material to researchers, laboratories and institutions conducting in-vitro or approved in-vivo investigation. It is not an FDA-approved drug and is not supplied or described for human or veterinary consumption. Suppliers commonly require buyers to confirm research intent at the point of purchase, and institutional buyers may need approvals from their own oversight committees before ordering.

Pricing varies widely across the market, so no single figure is meaningful. Per-milligram cost generally falls as batch size and order quantity rise, which is why suppliers publish quantity tiers, and rises with tighter purity specifications, additional analytics such as endotoxin or residual solvent testing, controlled lyophilisation and validated cold-chain packaging. Compare quotes per milligram of net peptide content rather than per vial, because gross vial weight includes counterion salt and water.

Overseas suppliers often quote lower per-milligram prices because they operate at larger synthesis scale, but the comparison is incomplete without the surrounding costs. Longer transit increases the chance of temperature excursion, customs can hold research chemicals, and independent verification of an unfamiliar lot adds analytical expense. A domestic mots-c supplier shortens the cold chain and makes re-testing and replacement practical within a research timeline.

Research-grade peptides are commonly specified at 98% or higher purity by reverse-phase HPLC, typically reported as percentage of total peak area at 214 or 220 nm. Purity alone is incomplete information, because it is a ratio and does not describe how much peptide the vial contains. Always read purity alongside net peptide content and the mass spectrometry trace.

A +16 Da peak indicates a single oxidised methionine residue, and +32 Da indicates both methionines oxidised. MOTS-c contains methionine at positions 1 and 6 plus a tryptophan at position 3, all of which are oxidation-prone, so this is a known vulnerability of the sequence. Oxidised material is chemically distinct from intact MOTS-c and should prompt a conversation with the supplier about handling and storage of that lot.

Lyophilised peptide is generally kept frozen, protected from light and moisture, and reconstituted solutions are handled under refrigeration for a limited working period. Specific temperature and stability windows should come from the supplier's own stability data for that lot rather than from generic advice, since formulation and fill practices differ between manufacturers. Repeated freeze-thaw cycles and light exposure are the two handling errors most likely to degrade an oxidation-sensitive sequence like this one.

A manufacturer runs the solid-phase synthesis, purification and analytical testing itself and can trace a vial back to a specific production run. A vendor purchases finished or crude peptide and repackages it under its own label, which means the documentation you receive originates upstream. Both models exist legitimately, but only the first can re-test a retained sample from your exact lot on request.

Real Peptides supplies research-grade peptides produced through small-batch synthesis with exact amino-acid sequencing, and every lot ships with a batch certificate of analysis. All material is supplied for laboratory research use only and is not an FDA-approved drug, nor is it offered for human or veterinary consumption. Current catalogue availability and specifications are listed on the Real Peptides website.

Because label weight is usually gross weight, not peptide weight. Peptides purified by RP-HPLC are typically isolated as trifluoroacetate salts, so the vial also contains counterion, bound water and residual salts, and net peptide content for TFA-salt peptides commonly sits somewhere in the 70 to 85% range. Two vials with identical labels can therefore differ meaningfully in actual peptide delivered, which is why price should be normalised to net peptide content.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA