Lactic acid is an organic compound that is produced both naturally and synthetically. It is an alpha-hydroxy acid (AHA) that can clear away dead skin cells and has antibacterial properties. This clear liquid also thickens shower gels.
Lactic acid helps to adjust acidity within a product, is a disinfectant and softens the keratin in the skin, improving its ability to hold moisture and softening it. It also helps to remove soap scum, prevents limescale and is antibacterial.
Lactic acid is produced commercially through a fermentation process using specific bacteria such as Lactobacillus, commonly used in probiotics, feeding on corn starch or beet sugar. They convert simple carbohydrates such as glucose, sucrose, or galactose to lactic acid. It is therefore considered a vegan ingredient, although it was originally discovered by Swedish chemist Carl Wilhelm Scheele in 1780 who extracted lactic acid from sour milk, giving the acid its ‘lactic’ name, which derives from the Latin for milk.
The acid has a long history of safe use and first started to be produced commercially by the German pharmacy Boehringer Ingelheim in 1895.