Exfoliating Ingredients for Glycerin Soap

When making glycerin soap that contains water and adding exfoliating enzymes like Papain, stability in water is a key factor.

Papain vs. Linked Papain vs. Encapsulated Papain

• Papaya Enzyme (Papain): Standard Papain powder is effective for exfoliating, but its main limitation is that it degrades relatively quickly when dissolved in water. While it can be added to the water phase, its activity will decrease over time in a liquid or water-containing soap base. It requires a pH of 5.5-7.0 and storage below 40°C, ideally refrigerated, for maximum stability.
• Linked Papain: This is a modified version of Papain that is cross-linked with a polymer. This modification significantly improves its stability when dissolved in water compared to standard Papain. It is supplied as a liquid and is soluble in water, working within a pH range of 5.0-7.0. It is more suitable for water-based formulas like your glycerin soap base than standard Papain.
• HyaCap™ Papain 16K (Encapsulated Papain): This version encapsulates the Papain enzyme within gel beads using Hyaluronic Acid. This encapsulation provides the best stability, even in water-based formulas and those containing surfactants, which are common in soaps. It is added at the end of the formulation process as gel beads and requires gentle stirring to distribute. It is highly stable and has a long shelf life.

Conclusion for your soap: For a glycerin soap base containing water, Linked Papain or, preferably, HyaCap™ Papain 16K would be more suitable than standard Papain powder due to their enhanced stability in water. HyaCap™ Papain offers the highest stability, making it the most robust option for a soap environment.

Other Exfoliating Options for Soap

Besides enzyme exfoliants like Papain, other types of exfoliants exist. Chemical exfoliants like AHAs (Alpha Hydroxy Acids) and BHAs (Beta Hydroxy Acids) are common, but they typically require an acidic pH (usually below 4.0) to be effective. Soap bases, especially traditional or melt-and-pour glycerin bases, often have a neutral to slightly alkaline pH, which is not compatible with the optimal working pH of AHAs/BHAs.

Enzyme exfoliants like Papain, Linked Papain, and HyaCap™ Papain are advantageous for soap formulations because they are effective at a more neutral pH (5.0-7.0), which is often more achievable and stable in certain soap bases (like syndet bars or some melt-and-pour bases) compared to the acidic pH required for AHAs/BHAs.

Physical exfoliants (like fine powders, beads, or grains) could also be added to soap for mechanical exfoliation, but your question specifically mentioned accelerating cell turnover, which is typically associated with chemical or enzymatic exfoliation rather than physical scrubbing.

Therefore, focusing on stable enzyme exfoliants like Linked Papain or Encapsulated Papain is a good approach for achieving enzymatic exfoliation in a water-containing glycerin soap base.