Heat, light and repeated freezing are what spoil a peptide. This page shows what most researchers do, and the typical lifespans they report.
Most researchers move vials to the fridge as soon as they arrive. Once mixed, a vial stays in the fridge and comes out only for use. About 30 days is typical, and up to 8 weeks for robust sequences, before potency starts to decline slowly.
Unmixed vials go straight into the fridge (2–8 °C), in the box and away from light.
Once a vial is mixed, it stays in the fridge. It comes out only for use and goes straight back.
About 30 days is typical, and up to 8 weeks for robust sequences. After that, potency declines slowly, and some researchers still use a vial beyond the window.
This is what most researchers report doing. For a specific peptide, the supplier's data sheet comes first. Common practice
| State | Temperature | Typical Lifespan / Potency Window |
|---|---|---|
| Before mixing (lyophilised powder) | Freezer (−20 °C to −80 °C) | 2 to 5 years |
| Fridge (2–8 °C) | 1 to 2 years | |
| Room temperature (about 20 °C and above) | A few weeks to 3 months at most | |
| After mixing (reconstituted) | Fridge (2–8 °C) | 14 to 30 days (up to 8 weeks at most for robust sequences) |
| Room temperature (about 20 °C and above) | 24 hours to 5 days (rapid potency loss) | |
| Frozen (aliquoted) | Several months, but repeated freeze–thaw cycles are avoided |
These ranges are the ones researchers commonly report. They come from experience, not from a single study. Common practice