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MOTS-c lab report: what to check on a MOTS-c COA
MOTS-c is a synthetic chain of 16 amino acids, with two methionines and a run of positively charged amino acids near its end. Those features decide what its lab report looks like: a mass spectrum with several charged signals instead of one, and oxidation as the first thing to look for. This guide covers what a MOTS-c certificate of analysis (COA) should show and how to check our own report. For the basics of any report, see How to read a peptide lab report.
The short version
What MOTS-c is, chemically
MOTS-c is a straight chain of 16 amino acids, written MRWQEMGYIFYPRKLR from their one letter codes. It starts with methionine, has a second methionine at position 6, a tryptophan at position 3, and three arginines and a lysine among its last five amino acids. The sequence was first found within a short stretch of mitochondrial DNA, which is where its name comes from.
| Reference fact | MOTS-c, as on our product page |
|---|---|
| Sequence | Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg |
| One letter code | MRWQEMGYIFYPRKLR |
| Form | Freeze dried (lyophilized) powder, 10mg and 20mg vials |
Purity: oxidation first
Purity comes from HPLC: the sample runs through a column, a UV detector draws a peak for each component, and purity is the MOTS-c peak as a share of every peak. With a tryptophan, two tyrosines and a phenylalanine, MOTS-c absorbs ultraviolet light well, so it gives a clear signal.
On a MOTS-c trace, the small peaks worth knowing are:
- Oxidized methionine. Each methionine can take up one oxygen atom with air, light or warmth. The oxidized form usually comes off the column a little before the main peak. With two methionines, a form with two extra oxygens is possible too.
- Oxidized tryptophan, which also takes up an oxygen atom, and is less common than oxidized methionine.
- Chains missing an amino acid, left from a synthesis step that didn’t finish. They sit close to the main peak, so a good method keeps them apart from it.
Oxidation happens in storage as well as in synthesis, which is why our product page lists minus 20 °C or colder, sealed and away from light and moisture. For how purity differs from the amount in the vial, see Purity vs content.
Identity: a family of signals
Mass spectrometry confirms the material is MOTS-c by weighing it. With four positively charged amino acids, MOTS-c usually picks up several protons in the instrument at once, so a report typically shows a family of signals instead of one.
Seeing the whole family, with each signal fitting the same mass, is what confirms the material is MOTS-c. The report should state that the measured mass matches the compound named on it. Oxidation looks like a small extra signal just to the right of each member of the family.
Content: milligrams, not percent
Content is how many milligrams of MOTS-c the lab measured in the vial. It is a separate number from purity: a vial can be very pure and still hold less than its label, or more, because the powder also holds salts and a little water. A report that gives content per vial, in milligrams or as a percent of the label, answers the question the label asks.
Our MOTS-c report
Our MOTS-c is listed with a report from Janoshik Analytical, test #169209 (June 5, 2026): 99.06% purity for a 10mg vial. The link on the product page opens the report on Janoshik’s own site (verify.janoshik.com), so you see it straight from the lab, not a copy. Like every report, it covers the sample that was tested, and the product page says so when the current lot isn’t confirmed as that sample.
Checking a MOTS-c report, step by step
- Name and sequence: MOTS-c, MRWQEMGYIFYPRKLR.
- Purity from HPLC, 98% or higher, with no large peak just before the main one (oxidized methionine).
- Identity confirmed by mass spec, with the measured mass matching MOTS-c.
- Content in milligrams, close to or above the 10mg or 20mg on the label.
- The report number opens the same report on the lab’s own site, #169209 for ours.
Common questions
Why does the mass spectrum show several signals?
Because the molecule rarely carries just one proton. The instrument reads mass divided by charge, so MOTS-c with two, three or four protons shows up at several places. Together those signals point to the same molecule.
Is a 20mg vial tested the same way?
Yes: purity and identity are the same questions at any size. Content is the one result that depends on the size, and it is compared with the vial’s own label.
Where do I find the MOTS-c report?
On the MOTS-c product page under Specifications & documentation, and on our research materials page, which lists every report.