Alternatives for Exfoliating/Whitening in Glycerin Bar Soap (Avoiding Liquefaction)

Question

I used Lactic Acid 88% in my glycerin bar soap formulation, and it caused the soap to liquefy. I am looking for alternative exfoliating/whitening ingredients that can be used at a concentration of 3-5% in a glycerin bar soap base without causing this issue. I am considering Sodium Lactate, Glycolic Acid, and Salicylic Acid. Are these suitable, and how should they be incorporated?

MySkinRecipes Expert · Accepted Answer

Based on your experience with Lactic Acid 88% causing your glycerin bar soap to liquefy, Sodium Lactate is a suitable alternative from the options you mentioned and available in our store.

Sodium Lactate helps to solidify bar soap and also provides moisturizing and gentle exfoliating/skin brightening effects. It is water-soluble and can be used at a recommended rate of 3-5% for accelerating skin cell turnover, which fits your desired concentration.

Glycolic Acid and Salicylic Acid, while effective exfoliants, may be less suitable for glycerin bar soap:

Glycolic Acid: Requires a low pH (below 4.0) to be effective, which can be difficult to achieve and maintain in a soap base and may affect the soap's structure and cause irritation.
Salicylic Acid: Standard Salicylic Acid is not water-soluble. While water-soluble forms exist, their primary benefit is pore exfoliation, and incorporating them into a soap base at 3-5% might still affect the soap's properties differently than Sodium Lactate.

Therefore, Sodium Lactate is the most recommended option for your glycerin bar soap formulation to achieve exfoliation and whitening without causing liquefaction.