Lactic Acid is an alpha hydroxy acid that exfoliates the skin. This 5% formulation offers very mild exfoliation & is supported with a purified Tasmanian pepperberry known to reduce signs of inflammation & sensitivity that is often associated with exfoliation. This formula contains a studied Tasmanian Pepperberry derivative to help reduce irritation associated with acid use. This derivative is of plant origin & varies in colour seasonally & this colour variation may be apparent in the formula from time to time. Contraindications: Lactic Acid should not be used on sensitive peeling or compromised skin. Please refer to additional sun protection note & other warnings in provided Directions. This p H of this formula is Approx. 3.8. Lactic Acid has a p Ka of 3.8 & p Ka is the most important aspect to consider in formulating with acids. p Ka implies acid availability. When p Ka is close to p H there is an ideal balance between salt & acidity maximizing effectiveness of the acid & reducing irritation. Higher p H numbers in such a case would increase salt which counter-intuitively would make the formula even more irritating than if the formula was more acidic. Note: While Lactic Acid can result in quick visible benefits we generally suggest indirect forms of skin exfoliation in favour of direct forms such as this formula due to potential inflammation & sensitivity associated with acids. Please refer to NIOD's Non-Acid Acid Precursor for such a reference.