Optiphen PLUS is a Natural Preservative. Optiphen+ is a unique paraben-free and formaldehyde-free liquid preservative system which consists of Phenoxyethanol in an emollient base of Caprylyl Glycol. Optiphen is a clear liquid preservative that can be easily added directly to the formulation during pre- or post-emulsification at or below 60 degrees C(140 degrees F). There are no ph restrictions in formulating with Optiphen. Optiphen is compatible with most ingredients used in the personal care industry.