Recommended Ingredients for Bar Soap

Based on your goal to create a bar soap for dry skin with moisturizing, whitening/brightening, and acne-reducing properties, and considering that many active ingredients are not effective in wash-off products, here are some ingredient recommendations suitable for soap:

• For Acne Reduction: You can use BioSulphur™ EQ (Water Soluble Sulfur). This ingredient is water-soluble and suitable for soap formulations, helping to reduce oiliness and acne.

• For Moisturizing/Softness: While much of a humectant like Glycerin will wash away, including Glycerin (USP/Food Grade) can still offer some benefit by attracting moisture during the short contact time. Additionally, PEG-75 Shea Butter Glycerides is a modified form of Shea Butter that is water-dispersible and designed for cleansing formulations, which can help provide a moisturizing feel in soap.

• For Brightening: It is challenging to achieve significant whitening results in a bar soap. Instead of direct whitening, you could focus on improving skin clarity and texture through gentle exfoliation. An ingredient like Bio-S Protease™ (Natural Enzymes For Exfoliation, Stabilized) could be considered for its ability to help exfoliate dead skin cells, which can contribute to a brighter appearance.

Regarding your question about using PE-1 Aqua or HyaCoat™:

• PE-1 Aqua is a penetration enhancer designed to help ingredients absorb into the skin. In a wash-off product like bar soap, which has a high pH and is quickly rinsed off, a penetration enhancer would not be effective and is not suitable.
• HyaCoat™ is a cationic hyaluronic acid designed to adhere to the skin. While it has substantivity, the harsh environment and high pH of traditional bar soap would likely compromise its structure and effectiveness. It is generally not recommended for use in bar soap formulations.

Remember that the efficacy of active ingredients in wash-off products is limited compared to leave-on products. The primary function of soap is cleansing.