Preservative for Salicylic Acid Toner

Regarding your formulation of Encapsulated Salicylic Acid (Liquid, Timed-Release, Wash-Off) 6.6% in water, you asked if a preservative is needed.

While Salicylic Acid itself does possess some antiseptic properties, as noted in the staff reply and the product description for Salicylic Acid (BHA), it is generally recommended to include a broad-spectrum preservative in water-based cosmetic formulations, even for wash-off products like your proposed toner.

Water is susceptible to microbial growth over time, which can lead to product spoilage, reduced effectiveness, and potential safety issues. Adding a preservative ensures the stability and safety of the product throughout its intended shelf life and use.

For your formulation, which is primarily water, suitable water-soluble, broad-spectrum preservatives would be appropriate. Examples include:

• Mild Preserved™ COS (pH 2-8, Broad Spectrum, No-Odor)
• NaturePreserve™ LB2 (pH 2.0-6.5, Natural Origin, Broad Spectrum)

Always follow the recommended usage rate for the chosen preservative and ensure compatibility with other ingredients in your formula. Performing a challenge test is recommended, especially if you plan to produce this formula for others.