With AHA and Hyaluronic Acid Mandelic Acid 10% + HA offers superficial dermal peeling that is gentler than other alpha hydroxy acids. The molecular weight of mandelic acid is 152.1 daltons which is larger than other alpha hydroxy acids (glycolic acid is 76.0 daltons, for example). This larger size allows mandelic acid to penetrate the skin more slowly which in turn makes it very gentle and suitable for all skin types. You don't need a concentration of more than 10%, because then you would simply be achieving an indirect peeling strength that is more easily offered through lower percentages of glycolic acid. Contraindications: This formula should not be used on sensitive, peeling, or compromised skin. Please refer to additional sun protection note and other warnings in provided Directions. Note: While exfoliating acids can result in quick visible benefits, we generally suggest the use of indirect forms of skin exfoliation in favour of direct forms such as this formula due to potential inflammation and sensitivity associated with acids. Please refer to NIOD's Non-Acid Acid Precursor for such a suggested formula. Directions Apply once per day, ideally in the PM. Can be diluted with other treatments to reduce strength until skin develops tolerance. Do not use on sensitive, peeling or compromised skin. Avoid contact with eyes. Contact of the product with the skin must be of limited frequency or duration. If irritation occurs, cease use and consult a physician. Use only as directed on unbroken skin. Patch testing prior to use is advised. Keep out of reach of children. Sunburn Alert: This product contains an alpha hydroxy acid (AHA) that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn. Use a sunscreen, wear protective clothing, and limit sun exposure while using this product and for a week afterwards. Sunburn Alert: This product contains an alpha hydroxy acid (AHA) that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn. Use a sunscreen, wear protective clothing, and limit sun exposure while using this product and for a week afterwards.