How can you tell if a reconstituted peptide has gone bad?

Signs of peptide degradation include visible changes such as cloudiness, turbidity, floating particles, or precipitate formation in a solution that was previously clear. Color changes or unusual discoloration may also indicate oxidation or chemical breakdown. At the molecular level, degradation involves deamidation, oxidation, and aggregation, though these changes are not always visible without laboratory analysis. When in doubt, if the solution appearance has changed from its original state or the peptide has exceeded its recommended storage timeframe, it should be discarded.