Stability and Efficacy of Hexylresorcinol AF in Low pH Formulations (pH 3.0-3.5)

Hexylresorcinol AF (e.q. Hentowhite) can be used in formulations with a pH of 3-3.5 effectively and stably.

Here are the details regarding its use in low pH conditions:

1. Stability: Hexylresorcinol is a highly stable molecule across a wide pH range (typically pH 3-10). Using it at pH 3-3.5 does not cause the active ingredient to degrade.
2. Efficacy: It remains effective at this pH level. In fact, Hexylresorcinol is frequently combined with Alpha Hydroxy Acids (AHAs) or other acidic exfoliating agents, which require a low pH to function, to provide synergistic brightening and anti-aging benefits.
3. Formulation Note: Since Hexylresorcinol AF contains fatty acids and surfactants to make it water-soluble, you should monitor the physical stability of your formula. At a very low pH, ensure that your overall emulsion or base remains stable and does not separate or become cloudy.

Usage Recommendations:

• Usage Rate: 1-3%
• Solubility: Water-soluble (can be mixed directly into the water phase or at the final step).
• Storage: Keep the finished product away from direct sunlight and heat to maintain long-term stability.

If your formula contains other sensitive actives, please ensure they are also compatible with a pH of 3-3.5.