The Ordinary

A Mild Lactic Acid Superficial Peeling Formulation

Lactic Acid is an alpha hydroxyl acid that exfoliates the skin. This 5% formulation offers very mild exfoliation and is supported with a purified Tasmanian pepperberry known to reduce signs of inflammation and sensitivity that is often associated with exfoliation. A stronger 10% formula is available here. 
This formula contains a studied Tasmanian Pepperberry derivative to help reduce irritation associated with acid use. This derivative is of plant origin and varies in colour seasonally and this colour variation may be apparent in the formula from time to time. 

Ingredients

Aqua (Water), Lactic Acid, Glycerin, Pentylene Glycol, Triethanolamine, Sodium Hyaluronate Crosspolymer, Tasmannia Lanceolata Fruit/Leaf Extract, Arginine, Potassium Citrate, Acacia Senegal Gum, Xanthan Gum, Trisodium Ethylenediamine Disuccinate, PPG-26-Buteth-26, Ethyl 2,2-Dimethylhydrocinnamal, PEG-40 Hydrogenated Castor Oil, Ethylhexylglycerin, 1,2-Hexanediol, Caprylyl Glycol.

Contradictions

Contraindications: Lactic Acid should not be used on sensitive, peeling or compromised skin. Please refer to additional sun protection note and other warnings in provided Directions. 
This pH of this formula is approximately 3.8. Lactic Acid has a pKa of 3.8 and pKa is the most important aspect to consider in formulating with acids. pKa implies acid availability. When pKa is close to pH, there is an ideal balance between salt and acidity, maximizing effectiveness of the acid and reducing irritation. Higher pH 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 and sensitivity associated with acids.