Compatibility of Copper Peptide with BHA and Retinal, and Papaya Enzyme Toner Usage

Based on the previous replies:

1. Using Papaya Enzyme (Papain) Toner: You can generally apply other skincare products immediately after using the 1% Papaya Enzyme toner as the first step. The exception is if the subsequent product is highly acidic or alkaline; in such cases, it's recommended to use them at a different time or wait for the toner to be fully absorbed before applying the next product.

2. Copper Peptide (GHK-Cu) Compatibility: The caution about not mixing Copper Peptide with AHA also applies to BHA (Salicylic Acid) because it is a chelating agent. However, Retinal (Retinaldehyde) can be used together with Copper Peptide.