Alcohol, Alcohol (Cognac)
Alcohol is a colourless, volatile liquid which is primarily produced by fermentation of sugar and starch-containing biomass. In natural cosmetics, it acts as a solvent for essential oils or cosmetically effective plants, as well as being an astringent and toning additive in facial toners, and preservatives in various cosmetic products. Oftentimes methylated spirit (denatured alcohol) is used in cosmetics with additives that make this alcohol inedible.
Pure alcohol is known to be well tolerated by the skin. Due to the fact that alcohol evaporates almost immediately after applying a product, it primarily has an effect on the product as opposed to the skin and helps in the absorption of other ingredients.
see Heike Käser 2010, "Naturkosmetische resources", Linz, Freya Verlag, 3rd Edition 2012