Preservative Efficacy: Ethylhexylglycerin vs. Phenoxyethanol SA

Regarding the broad-spectrum efficacy (against mold and bacteria) of Ethylhexylglycerin and Phenoxyethanol SA within the pH range of 5 to 6.5:

Both Ethylhexylglycerin and Phenoxyethanol SA can provide sufficient broad-spectrum protection against mold and bacteria at a 1% usage rate within the pH range of 5 to 6.5.

• Ethylhexylglycerin: This ingredient is a gentle preservative and also acts as a humectant. While it can withstand a wide pH range (2-12), it is generally not suitable for use as a single preservative in a formula and should be used in combination with other preservatives for effective broad-spectrum coverage.
• Phenoxyethanol SA: This product (equivalent to Optiphen Plus) is a blend of Phenoxyethanol, Caprylyl Glycol, and Sorbic Acid. It is designed as a very safe, broad-spectrum preservative. Its optimal pH range for use is 2.0-6.0, which includes the specified range of 5 to 6.5, making it effective for broad-spectrum control in this condition.

In summary, while both can be effective in the 5-6.5 pH range at 1%, Phenoxyethanol SA is formulated as a complete broad-spectrum system for this range, whereas Ethylhexylglycerin typically requires co-preservatives to achieve broad-spectrum efficacy.