Quick answer
When sourcing MOTS-c for research, require HPLC purity with a batch trace, mass-spec identity near 2,175 Da, and a lot-specific CoA matching the vial.
- Identity: 16 residues, about 2,175 Da; two methionines can oxidize (+16 Da each)
- Must-haves: batch HPLC trace, mass-spec confirmation, lot number matching the vial
- Listing: V8 MOTS-c page: 10 mg lyophilized, ≥98% HPLC listed
- Concentration: mg ÷ mL; use the calculator
- Documents: CoA library
For laboratory research use only; not for human consumption.
What MOTS-c is, and why the origin matters for sourcing
MOTS-c is a 16-residue mitochondrial-derived peptide, Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg (formula C101H152N28O22S2, about 2,175 Da). It is encoded by a short open reading frame within the mitochondrial 12S rRNA gene rather than the nuclear genome that produces most peptides researchers handle. The original description is Lee et al., Cell Metabolism 2015, listed in the references.
The unusual origin does not change the sourcing fundamentals. Purity, identity confirmation and lot traceability matter exactly as much as for any other synthetic peptide. It does mean that a supplier's documentation should draw a clear line between the synthetic research reagent and the endogenous biology it is meant to model. Background on the compound is in the MOTS-c research overview, with an accessible introduction in what is MOTS-c.
| Property | MOTS-c |
|---|---|
| Sequence | Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg |
| Length | 16 residues |
| Formula | C101H152N28O22S2 |
| Approximate average mass | About 2,175 Da |
| Sensitive residues | Two methionines (oxidation), one tryptophan, two tyrosines |
| Supplied form | Lyophilized powder, 10 mg vial (per the MOTS-c product page) |
Who is buying MOTS-c
The legitimate buyer set for MOTS-c is narrow: academic labs studying mitochondrial signaling or metabolic-stress biology, biotech groups running early-stage metabolic research, and contract research organizations executing assays for clients. A supplier that markets MOTS-c to any audience outside laboratory research, with instructions or outcome claims aimed at individual use, has a documentation and compliance problem independent of any purity data it publishes. A purchase should fit a stated research purpose, and the research-use-only labeling should be present on both the listing and the vial.
What to check before ordering
- HPLC purity with a batch-specific chromatogram. A stated percentage with no supporting trace is not verifiable. See understanding HPLC purity.
- Mass spectrometry identity confirmation. At 16 residues, MOTS-c is short enough that a truncated or deletion-sequence impurity can produce an HPLC profile similar to the intact peptide. A mass near 2,175 Da closes that gap; HPLC purity alone does not. See HPLC vs. mass spectrometry.
- Lot-specific certificate of analysis. A generic certificate with no lot number is not meaningful documentation, however complete it looks. See how to read a CoA.
- Lot traceability on the vial. The printed lot number should match the certificate on file. If a supplier cannot produce a certificate for the specific lot shipped, regard that as a hard stop.
- Storage and handling guidance consistent with a lyophilized peptide. See what is lyophilization.
MOTS-c-specific analytical points
Two features of the sequence shape what a good certificate shows. First, MOTS-c has two methionines. Methionine oxidizes to the sulfoxide, adding 16 Da per oxidized residue, and the oxidized forms elute earlier than the parent on reversed-phase HPLC. A lot stored warm or exposed to air can accumulate +16 and +32 Da species. A mass spectrum that shows only the parent mass, or reports the oxidized fraction, is more informative than a single purity percentage.
Second, the peptide is rich in basic residues (two Arg near the C-terminus, plus Lys and a further Arg at position 2) and contains tryptophan and two tyrosines, so it absorbs at 280 nm as well as at the peptide-bond wavelength of 214–220 nm. In practice the peptide behaves as a moderately hydrophobic basic 16-mer, and its mass is typically observed as multiply charged ions. The verification workflow in detail is in MOTS-c purity testing.
| Mass observed | What it suggests |
|---|---|
| About 2,175 Da | Intact MOTS-c |
| +16 Da | One methionine oxidized |
| +32 Da | Both methionines oxidized |
| Lower by a residue mass | Deletion or truncated sequence |
Synthetic reagent versus endogenous peptide
A certificate of analysis confirms that a purchased vial contains the correct 16-residue synthetic sequence at a stated purity. It says nothing about how MOTS-c is produced, transported or regulated inside a mitochondrion. That distinction matters when interpreting results built on a purified synthetic reagent: observations after adding synthetic MOTS-c can test responsiveness to the molecule itself, but they do not by themselves explain the endogenous production or regulation behind its proposed AMPK-linked mechanism. Reputable suppliers keep this distinction explicit in their materials rather than blurring reagent data with claims about endogenous biology. For how MOTS-c relates to other peptides encoded in mitochondrial DNA, see MOTS-c vs. other mitochondrial-derived peptides.
Why price still tracks production cost
Solid-phase synthesis, reversed-phase purification, mass-spec confirmation and lyophilization all carry real costs. A 16-residue chain is more expensive to make cleanly than a short peptide because there are more opportunities for coupling failures and truncated byproducts. A price with no plausible relationship to that process is worth questioning before it is worth ordering. The common shortcut at the low end is skipping mass-spec confirmation and relying on HPLC purity alone, which is exactly the gap described above. The broader pattern is described in red flags when buying research peptides.
Receiving and logging a MOTS-c lot
On arrival, check that the seal is intact, the label shows the compound name and lot number, and the powder looks like a uniform cake or film with no discoloration or visible moisture. Photograph the vial and record the date, then move it to cold storage promptly. Log the lot number in the lab notebook for every experiment that uses it, because a later question about reproducibility is far easier to answer when each result is tied to a specific lot and its certificate.
Questions to put to a supplier
A short written query before ordering shows a lot about how a supplier works. Useful questions: Can you send the certificate for the current lot before I buy? Which method and column were used for HPLC? What mass did the spectrum show, and which ions were used? Which laboratory ran the analysis, and on what date? How is the lot number marked on the vial? A supplier with real batch records answers these directly and quickly. Vague, evasive or templated answers tell you that the documentation may not exist in the form implied. Keep the replies with your lab records, since they become part of the provenance of any data generated with that vial.
Planning handling before you order
The product page specifies refrigeration at 2–8 °C, or −20 °C for long-term storage, protected from heat, moisture and light. Because of the two methionines, minimizing air exposure and time in solution is sensible. Stock concentration is simple arithmetic: peptide mass divided by diluent volume. A 10 mg vial reconstituted in 2 mL gives 5 mg/mL on a gross-mass basis, and the peptide calculator does the same for any volume. Net peptide content is below gross powder mass because of counter-ions and moisture. Specific handling parameters are in MOTS-c reconstitution and storage.
Where to buy documented MOTS-c
V8 Peptides supplies MOTS-c as a lyophilized powder, listed at ≥98% HPLC purity, in a 10 mg sealed glass vial, with batch-specific documentation that covers identity, purity, lot number and test date. The product page is MOTS-c research vial. Published certificates are in the CoA library; the badge on the product page shows whether the certificate for a particular lot is posted, so confirm it for the lot you receive. For a general framework on evaluating any research peptide supplier, see the supplier checklist.
Research Use Only. For laboratory research use only; not for human consumption. This article is research education, not usage guidance.
Frequently asked questions
What is the molecular mass of MOTS-c?
About 2,175 Da (average mass) for the 16-residue sequence, formula C101H152N28O22S2. A mass spectrum should show this value for an intact lot.
Why is mass spectrometry essential for MOTS-c?
Truncated and deletion peptides can look similar to the intact peptide by HPLC. Only mass confirms the sequence length and composition.
Why do methionines matter?
MOTS-c has two methionines. Oxidation adds 16 Da per residue and produces earlier-eluting peaks, so stored or mishandled lots can show +16 and +32 Da species.
Does a certificate say anything about endogenous MOTS-c?
No. It confirms the identity and purity of the synthetic reagent only. Endogenous production and regulation are separate biology.
Who should be buying MOTS-c?
Qualified laboratory researchers, such as academic, biotech and contract research groups. A supplier that markets it for individual use is a red flag.
How do I calculate the concentration of a reconstituted stock?
Divide the vial mass by the diluent volume: 10 mg in 2 mL is 5 mg/mL gross. The calculator returns the same result.
How should lyophilized MOTS-c be stored?
Per the product page, at 2–8 °C or −20 °C long term, protected from heat, moisture and light.
What should I do if the lot number on the vial does not match the certificate?
Regard it as a hard stop and ask the supplier for the certificate that corresponds to the lot shipped before using the material.
References
- Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism. 2015;21(3):443-454.
- V8 Peptides. MOTS-c research overview.
- V8 Peptides. MOTS-c purity testing.
- V8 Peptides. MOTS-c reconstitution and storage.
- V8 Peptides. MOTS-c research vial: product specifications.