Can you share a source ?
This is what ChatGPT says
Short answer: No, GHK-Cu does not significantly degrade when mixed with BAC (bacteriostatic water) if it’s prepared and stored correctly.
Details
Compatibility: GHK-Cu is generally stable in BAC water (0.9% benzyl alcohol). BAC is commonly used for peptide reconstitution to reduce bacterial growth.
Copper binding: The copper in GHK-Cu remains chelated (bound) and is not disrupted by benzyl alcohol.
pH: BAC water is close to neutral, which is suitable for GHK-Cu stability.
Best practices to minimize degradation
Storage: Keep reconstituted GHK-Cu refrigerated at 2–8 °C.
Light: Protect from light (amber vial or keep in the dark).
Handling: Avoid repeated warming/cooling cycles and excessive agitation.
Shelf life:
With BAC water: typically 2–4 weeks refrigerated (some users report longer, but potency may slowly decline).
With sterile water (no preservative): use within a few days.
When degradation can occur
Exposure to heat, UV light, oxidation, or contamination.
Prolonged storage beyond recommended timeframes.
If you want, tell me how you’re using it (topical vs injectable) and your intended storage duration, and I can tailor the recommendation more precisely.