Laboratory quality
Stability testing
How long a peptide remains within specification under defined storage conditions, and why stability is not a single number.
- Last updated:
- 2026-07-22
Overview
Stability testing tracks a peptide over time under a defined storage condition and asks: is it still within specification (identity, purity, potency, sterility, endotoxin) at each time point? Real-time stability studies run at recommended storage temperature; accelerated stability studies run at elevated temperature to predict long-term behaviour more quickly.
Stability is condition-dependent. A peptide that is stable for two years at −20°C may be stable for weeks at 4°C and days at room temperature.
Why it matters
The storage windows quoted on compound pages come from stability data. Ignoring the storage condition changes the effective peptide mass in the vial without changing what the label says.
Key concepts
Real-time vs. accelerated
Real-time studies observe the material for the intended shelf life at the intended condition. Accelerated studies use elevated temperature to force degradation and infer longer-term behaviour.
Failure modes
Common peptide failure modes include oxidation (of methionine or tryptophan), deamidation, hydrolysis at labile bonds, and aggregation. Different peptides fail differently.
Reconstituted-solution stability
Stability of a reconstituted solution is generally shorter than stability of the dry vial and is more sensitive to temperature and to repeated access.
Common misconceptions
- "Stable" without a condition is meaningless. A peptide is stable at some condition, unstable at another.
- "Long shelf life" does not mean the vial is fresh. Manufacturing date matters.
- Freezer storage is not always the answer. Some peptides tolerate freeze–thaw cycles poorly.
Practical interpretation
Follow the compound page's storage window for both the dry vial and the reconstituted solution. If the storage condition was not maintained (unrefrigerated shipping, freezer failure, accidental warming), the storage-window guidance no longer applies to that vial.
Limitations
Healthy Mango does not run stability studies. Storage windows on compound pages are derived from published sources and reference materials.