As I’ve explained in my last Hairvember blog post, every hair care routine should start with the quest for a shampoo that is based on a surfactant mix adapted to your hair. But even though finding the right surfactants can be quite the challenge in and of itself, I am afraid there are just a few more aspects and ingredients to consider when it comes to washing your hair: In today’s blog post, I want to discuss the matter of alcohol. In shampoos… In mulled wine, mark you, it is perfectly alright 🙂
First of all, let’s note that there are two kinds of acohols with very different properties we must take into consideration when putting shampoos to the test. Fatty alcohols like Lauryl/Cetyl/Myristyl/Stearyl/Cetearyl alcohol and Behenyl are usually derived from natural sources. They have a polar hydroxyl group (i.e. an oxygen atom bonded to a hydrogen atom) that is bonded to one of the carbons in a non-polar carbon chain of (usually) 12 to 20 carbons. Short-chain alcohols on the other hand have got less than 3 carbons in the tail.
Because of the significantly higher number of carbons, long-chained alcohols are oily or “fatty”: They work as excellent emollients and moisturizers in shampoos and other beauty products. It would therefore be inaccurate to say that alcohol always dries out your hair. Quite the contrary, fatty alcohols are not only perfectly safe to use, they even help your hair stay moisturized.
Short-chain alcohols like Alcohol denat., ethanol, Isopropyl alcohol, Propanol, Propyl alcohol, SD alcohol and SD alcohol 40 on the other hand are not added as moisturizing agents, but mainly as emulsifiers, to improve a shampoo’s “spreadability” and because of their antibacterial properties (the main ingredient of any shampoo being water, it is indeed necessary to prevent bacterial and fungal spoilage). They have the advantage to evaporate quickly, which however leads to additional drying effects. Also, remember that these kinds of alcohols are used as detergents in household products for a reason: In shampoos, they remove the skin’s and hair’s natural oils just a little bit too efficiently, especially when they are added to formulations that already contain harsh surfactants.
One could therefore say that if you are looking for milder shampoos, you should keep away from products containing bigger amounts of short-chain alcohols. Unfortunately however, on must add that other preservatives (which, as I’ve stated above, are necessary in liquid shampoos!) might be even more irritating: Some are even considered dangerous for your overall health, which is why natural and organic cosmetic brands mainly rely on short-chain alcohols as preservatives. I am planning to do a separate blog post on preservatives in shampoos during Hairvember, so keep your eyes peeled for that 🙂
The bottom line for now would have to be, once more, that finding the right shampoo is about finding a balance between harshness and mildness, between effectiveness and undesirable side effects; about weighing the pros and cons of certain ingredients and deciding for yourself whether you want to put up with the disadvantages of the one or the other. But in order to take these decisions, you need information, and I hope you found my post helpful in this perspective 🙂