Alcohols are on a bad voice, just like silicones and parabens. When we see an ingredient with an alcohol ending on the product, we automatically categorize it as bad. But can all products containing any kind of alcohol be declared as bad or are we just being too general?
What are alcohols and what is their function?
Alcohols are compounds having an -OH (hydroxyl) group attached to a carbon atom in the alkyl group. The group may be attached to a primary, secondary or tertiary C atom, so we separate primary, secondary and tertiary alcohols.
Primary alcohols include methanol, ethanol, isopropyl alcohol and others. Secondary alcohols include 1-propanol and 2-propanol and others. There are also alcohols with two, three or more -OH groups, which we call diols, triols, etc. Among the most famous poliols are glycerol, ethylene glycol, propylene glycol, erythriol, and others.
Alcohols have several functions in cosmetic products. They are mostly used as solvents or co-solvents, and in high concentrations they posess antimicrobial properties, and therefore products do not need a preservative.
“No alcohol” doesn’t mean no alcohol
For many years cosmetic manufacturers have marketed certain cosmetic products that do not contain ethyl alcohol (also known as ethanol, or grain alcohol) as “alcohol free”. However, “alcohols” are a large and diverse family of chemicals, with different names and a variety of effects on the skin. This can lead to some confusion among consumers when they check the ingredient listings on cosmetic labels to determine alcohol content.
In cosmetic labeling, the term “alcohol,” used by itself, refers to ethyl alcohol. Cosmetic products, including those labeled “alcohol free,” may contain other alcohols, such as cetyl, stearyl, cetearyl, or lanolin alcohol. These are known as fatty alcohols, and their effects on the skin are quite different from those of ethyl alcohol.
Should any alcohol be avoided?
When we think about “bad” alcohols, alcohol denat, ethanol, isopropyl alcohol and SD Alcohol (which means “specifically denatured alcohol”) are the first we think of. These alcohols are commonly used as solvents for cosmetically active ingredients that are insoluble in water. The use of these compounds in cosmetics leaves a cool feeling on the skin, as the alcohol evaporates faster than water, while giving the products a “light-weight” texture. They also help with the penetration of cosmetically active compounds into the skin. Everything okay until now, right? But these alcohols are reputable to irritate the skin and dry it.
Ethanol or ethyl alcohol
Ethanol is widely used in all types of products to which our skin is directly exposed. Scientific literature contains contradictory evidence of the safety of such topical alcohol applications.
Ethanol is known to improve the penetration of other substances and can be used in transdermal delivery systems. In his study, Bommannan found that ethanol enters the skin in vivo and removes measurable amounts of lipids from the surface of the skin. Removing the lipid layer can reduce the function of the skin barrier, which makes the skin more permeable. Because the skin is more permeable, a larger transepidermal loss of water and less hydration of the epidermis results in further skin dryness. Longer use can cause dry, leaking skin due to a reduced amount of lipids and moisture and also causes local inflammation.
Alcohol denat is an abbreviation for denatured alcohol, which is used in cosmetics and personal care products. Denatured alcohol is a denaturant containing ethanol. The usual denaturants in cosmetic products and personal care products are: denatonium benzoate, t-butyl alcohol, diethyl phthalate and methyl alcohol. The method of denaturing alcohol does not chemically change the ethanol molecule.
Denatured alcohol is generally noted as alcohol Denat or SD (especially denatured) alcohol.
It acts as anti-foaming agent, adstringent, antimicrobial agent and solvent. One of the main reasons for the use of denatured alcohol is its adstringent action. Adstringent is a substance that reduces the permeability of the mucous membrane or skin and capillaries, thereby reducing the inflammatory response and sensitivity to external influences. Adstringent interacts with certain functional groups, in particular sulfhydryl, on the surface of the proteins, and thus causes their precipitation. Adstringents cool the skin and cause temporary toning effect.
Use of denatured alcohol
Denatured alcohol is commonly used in acne treatment. The product containing denatured alcohol dries faster, which gives it a cooling effect and immediately degreases the skin. However alcohol-based products can actually encourage sebaceous glands to produce more oils, which causes the skin to become even oilier than before. Excessive sebum production combined with irritation that may be caused by denatured alcohol can lead to increased acne production.
In case of long-term use of skin care products containing high concentrations of denatured alcohol, dryness and irritation may occur. Denatured alcohol can also cause erosion of the surface layer of the skin, leading to a weakened skin barrier.
Denatured alcohol is common in post-shave products, where the skin needs an adstringent effect. Often it is also found in sunscreens because it is a good solvent for UV filters in plays a role in their distribution over the skin.
Isopropyl alcohol or 2-propanol is a flammable liquid that is obtained from propylene. It is a solvent that acts as a anti-foaming agent, an adstrigent and a viscosity reduction agent.
A spray with an isopropyl alcohol concentration of 80.74% did not show any possibility of dermal sensitization in 9 human participants. In one of the studies, it has been shown that isopropyl alcohol strongly irritates the eyes of rabbits, at a concentration of 70% of the solution in water.
Isopropyl alcohol, which some consumers consider that dries skin, is rarely used in cosmetics.
Let’s not throw everyone in the same basket, not all alcohols are bad!
So, many products on the market are labeled ” free of alcohol ” and then a look at the INCI list reveals compounds that end with the name alcohol. Is this a trap? Should we throw a bad light on such products? No. Not all alcohols are bad. Many cosmetic alcohols, such as cetyl alcohol, stearyl alcohol, cetearyl alcohol, myristyl alcohol, behenyl alcohol and lanolinic alcohol, are also used in cosmetics.
These are long-chain aliphatic alcohols (usually between 12 and 18 carbon atoms), which are often used in lotions and creams. They serve as emollients, plasticisers, emulsion stabilizers, foam stabilizers and viscosity control agents.
Cetyl alcohol is used primarily as a softener to prevent drying and cracking of the skin due to its water binding ability.
What do you think about alcohols in cosmetics?
Sources: Lachenmeier DW. Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity. J Occup Med Toxicol., Final Report of the Safety Assessment of Alcohol Denat.,
Final Report on the Safety Assessment of Cetearyl Alcohol , Cetyl Alcohol , lsostearyl Alcohol , Myristyl Alcohol , and Behenyl Alcohol, FDA