When using copper peptides in skincare, it is important to avoid certain combinations to ensure the safety and efficacy of the product. Here are some ingredients that should not be mixed with copper peptides:

1. Vitamin C: Copper peptides can react with vitamin C, leading to oxidation and potentially causing skin irritation. It is best to use these ingredients at different times or choose products that already combine them in a stable formulation.

2. AHAs/BHAs: Alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs) are exfoliating agents that can lower the pH of the skin. This acidic environment can destabilize copper peptides, reducing their effectiveness. It is recommended to use these ingredients in separate routines or alternate their usage.

3. Retinol: Copper peptides and retinol can interact and reduce each other's efficacy. It is advisable to use them at different times, such as retinol in the evening and copper peptides in the morning, to avoid any potential interaction.

4. Benzoyl Peroxide: Benzoyl peroxide is commonly used to treat acne, but it can oxidize copper peptides and reduce their benefits. It is best to avoid using these ingredients together or space out their application.

5. Strong acids or alkaline products: Extremely acidic or alkaline products can disrupt the stability of copper peptides. It is important to avoid combining them with such products to maintain their efficacy.

Always read product labels and consult with a skincare professional to ensure compatibility and maximize the benefits of your skincare routine.