Denatured alcohol (alcohol denat. or SD alcohol) is a very fast-drying, synthetic chemical that may appear on your label as methylated spirit, grain alcohol, denatured rectified spirit, or fermentation alcohol. It’s prepared by combining toxic denaturants (additives) with drinking alcohol, rendering it unfit for human consumption. This way, personal care product manufacturers are able to evade the heavy excise duties some countries impose on drinking alcohol.
Many chemicals can be used as denaturants, e.g. benzene, kerosene, mercuric iodide, boric acid, formaldehyde solution, camphor, coal tar, hydrochloric acid, gasoline (petrol), iodine, chloroform, wood naphtha, ethyl acetate, pyridine, denatonium benzoate, acetone, isopropyl alcohol, methyl ethyl ketone, and methanol. As you can see, some of these denaturants can be dangerous to human health. Based on the nature of the denaturants used, denatured alcohol can be classified either as completely denatured (CD) or specially denatured (SD). CD alcohol is obtained from crude and partially refined denaturants whilst SD alcohol is derived from high quality denaturants.
Denatured alcohol is quite cheap. It’s included in both ‘natural’ and mainstream products as mild solvents, penetration enhancers, preservatives, astringents (to shrink pores and tighten skin), and fast-drying agents - with some cooling effect. It can be found in many antiperspirants, perfumes, soaps, shampoos, hair and scalp products, mouthwashes, lotions, and creams.
Exposure to denatured alcohol is through ingestion, inhalation and skin contact. It acts as a penetration enhancer, stripping away the skin’s barrier and allowing irritants, allergens, bacteria, and viruses to attack the skin. The disruption of the barrier also allows the skin to absorb unwanted chemicals from the product you’re using and from the environment.
Denatured alcohol causes skin redness, irritation, and dermatitis. It also promotes programmed cell death (apoptosis) in skin cells even at low concentrations, and worsens the condition of acne. It dehydrates the skin making the appearance of fine lines and wrinkles more perceptible. Inhalation can cause watering of the eyes, dilation of the pupils, spotted vision, respiratory tract irritation, dizziness, headaches, nausea, and convulsions, as well as central nervous system effects. It’s even been linked with reproductive and birth defects.
Denatured alcohol has several other applications. It can be used to remove stains and dirt, e.g. inks, greases, glues, waxes and paints. When mixed with varnish or shellac, it can serve as wood protector. It’s used as fuel for alcohol burners and camping stoves. It can also be used to kill molds and mildews and for sanitation purposes. It’s useful in the formulation and processing of yeast, fungicides, insecticides, lacquer, thinners, liniments, rockets, explosives, detonators, brake fluids, disinfectants, embalming fluids, incense, photographic films, and fuel for automobiles, jets, rockets, and airplanes.