The questions below are the ones researchers ask most about storing, mixing and handling MOTS-c. Each answer reflects the peptide’s sequence, Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg, and links to the fuller page where there is one.
How long does MOTS-c last in the fridge after mixing?
Mixed with bacteriostatic water and kept at 2 to 8 °C in the dark, MOTS-c lasts 8 to 12 weeks under Vistara Labs’ handling guidance, with quality slowly fading from around week 6 to 8. No published stability study covers MOTS-c in solution, so the window is general peptide guidance. The full table is on how long MOTS-c lasts.
How long does unmixed MOTS-c powder last?
Sealed, dry and frozen, MOTS-c powder keeps for a year or more; one chemical supplier rates the solid at 4 years or more at minus 20 °C (Cayman Chemical, item 29785). Sealed vials in use over the coming weeks can sit in the fridge. Days at room temperature in transit do not harm it, so it ships without an ice pack.
Why is MOTS-c sensitive to oxidation?
Its sequence carries two methionines, at positions 1 and 6, and a tryptophan at position 3. Methionine reacts with dissolved oxygen to form methionine sulfoxide, and tryptophan oxidises under light (Manning et al., Pharmaceutical Research, 2010). Two oxidation products of MOTS-c were characterised in a plasma detection method (Knoop et al., Rapid Communications in Mass Spectrometry, 2019).
Can you tell if MOTS-c has oxidised by looking at it?
Not reliably. Methionine sulfoxide is colourless, so a solution can look perfect after its methionines have changed. A yellow tint points to tryptophan or tyrosine oxidation and means the solution is discarded. The mixing date on the label is the better guide.
What do you mix MOTS-c with?
Bacteriostatic water, which is sterile water with 0.9% benzyl alcohol so a refrigerated vial can be accessed more than once. MOTS-c has three arginines and a lysine and carries a strong positive charge at that pH, so it dissolves without acid or other solvents. The reasons are on the MOTS-c solubility guide.
How much bacteriostatic water goes in a 10 mg MOTS-c vial?
There is no single correct volume. With 2 mL a 10 mg vial gives 5 mg/mL; with 1 mL it gives 10 mg/mL. The 40 mg vial gives 10 mg/mL with 4 mL. More water spreads the same amount of peptide through a larger volume, so write the chosen concentration on the vial. The tables and calculator are on the MOTS-c reconstitution page.
Why is my MOTS-c cloudy after mixing?
Brief cloudiness that clears within 10 to 15 minutes is usually trapped air from adding water too fast or shaking. Haze that persists, strands, particles or a tint that appears later point to warm storage, freezing or contamination, and the solution is discarded. More in why peptides gel or go cloudy.
Can you freeze mixed MOTS-c?
Not a vial that will be opened again, because repeated freezing and thawing promotes aggregation in peptide solutions. Laboratories that need frozen solution divide it into single-use aliquots, filled well to limit headspace air, and thaw each one once. Sealed powder can be frozen at minus 20 °C without concern.
Does MOTS-c need to be kept out of the light?
Yes, more than most peptides. It has a tryptophan, two tyrosines and a phenylalanine that absorb ultraviolet light and start photo-oxidation, and two methionines those reactions can reach. Keep the vial boxed in the dark in the fridge and out of room light on the bench.
Where does MOTS-c come from?
It is encoded in mitochondrial DNA, in a short open reading frame within the 12S ribosomal RNA gene, and was named mitochondrial open reading frame of the 12S rRNA-c by the group that described it (Lee et al., Cell Metabolism, 2015). Research vials contain the synthetic human sequence. More is in the MOTS-c research reference.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
