Whitening and Exfoliating Ingredients for Glycerin Soap (pH 5-7)

For a solid glycerin soap base with a pH between 5-7, you can incorporate ingredients that help with skin whitening. Achieving effective chemical exfoliation at this pH range in a soap base is challenging, as many common chemical exfoliants work best at lower pH levels.

Here are some whitening ingredients compatible with your soap base's pH:

• Alpha Arbutin: This water-soluble ingredient helps brighten skin and reduce melanin production. It is effective and safe for use within the pH range of 3.5-6.5, which is suitable for your soap base. It can be added to the melted soap base, ensuring the temperature is below 30°C when adding.
• Kojic Acid Dipalmitate: This is an oil-soluble derivative of Kojic Acid that is more stable and can be absorbed better. It works to reduce melanin production and is compatible with a pH range of 3-9, fitting within your specified range. It needs to be dissolved in an oil phase with heat (around 60°C) before being incorporated into the melted soap base.

Both Alpha Arbutin and Kojic Acid Dipalmitate can be used together to enhance the whitening effect. Please refer to the product descriptions for recommended usage rates for each ingredient.

Regarding exfoliation, while chemical exfoliation is difficult at this pH, you might consider adding gentle physical exfoliants if desired, though these were not part of the search results.