Regarding Accidental Over-Concentration of Phenoxyethanol

It's understandable to feel regret when ingredients are wasted, especially valuable ones like Alpha Arbutin. However, the advice you received is correct and crucial for skin safety.

Preservatives like Phenoxyethanol are designed to kill microorganisms. While essential in small, recommended amounts to keep a product safe from contamination, using them at much higher concentrations than intended can also harm skin cells.

Attempting to separate the excess Phenoxyethanol by letting it settle and pouring off the water layer is unlikely to result in a mixture with a safe and effective concentration. The distribution might not be uniform, and you cannot be certain of the final percentage of preservative remaining in the Alpha Arbutin solution.

Given the significant amount of Phenoxyethanol accidentally added, the safest course of action for your skin's health is to discard the mixture. It's better to lose the ingredients than risk a severe skin reaction.

For future formulations, always measure ingredients carefully, especially potent ones like preservatives, to ensure they are used within their recommended safe ranges.