About the author: FutureDerm.com is proud to introduce John Su on our staff as a Contributing Writer. John is an established skin care expert and aspiring dermatologist. He also runs a blog, The Triple Helix Liaison, dedicated to providing unbiased, meaningful, and insightful information about skin care. For his full bio, please visit our About page.
As I explained last week in The 5 Most Common Mistakes Even Skin Experts Make, it is well-established that ethanol can reduce water content via a form of water loss known as transepidermal water loss (TEWL) (1), lipid content via extraction and dissolution (2), and protein content via denaturation (3). These properties allow for ethanol to be an effective (and drying) penetration enhancer. But what does that mean in the context of skin care?
In terms of its DRYING ability, ethanol can be a positive or negative attribute of any given product, depending on its function. If used to “compress” layers of product by encouraging the evaporation of various filler ingredients like cyclic silicones, it’s a positive ingredient. If used to chronically remove sebum from oily skin types, it’s a negative ingredient, drying out the skin.
But make no mistake here. Ethanol in itself isn’t harmful. It’s the drying effect that can lead to other problems. Dry skin is inherently more susceptible to issues such as a weakened epidermal barrier, which leads to less protection, which can lead to inflammation, which can quicken the aging process (4).
Contrary to popular belief, unlike ingredients such as benzoyl peroxide, ethanol doesn’t generate oxidation within the skin (or reactive oxidative species, AKA ROS). It just makes skin drier, which consequently, ages faster than oily skin types.
But before you jump to conclusions, note that dry skin types only innately or inherently age faster than oily skin types. This concept only remains valid if both skin types never apply moisturizer or use adequate antioxidant and sun protection. With proper moisturization and protection, someone with dry skin can age just as gracefully as one with oily skin. Not to mention that the former skin type doesn’t have to worry about acne.
We all know that excessive oral consumption of ethanol in alcoholic beverages leads to increased risks of various types of malignant diseases such as oral, hepatic, and breast cancer. But can skin cancer be casually related to topical ethanol application? Fortunately, no studies have ever shown a link between topical ethanol application and skin cancer! However, a few studies have shown in animal models, that ethanol in conjunction with Aloe emodin (a component of Aloe Vera) and UV light can increase the risk of cancer by alteration of the p53 gene (7). However, if adequate amounts of UVA and UVB sun protection are used, this shouldn’t be an issue.
Therefore, the only other source of concern is the amount, if any, of topically-applied ethanol that is able to penetrate through intact skin and enter the blood stream, where it will have the same effects in the body as those known from oral consumption. Fortunately, all studies indicate that no measurable elevations in blood alcohol levels were detected (8). Only one study indicated a higher-than-normal blood alcohol level, and the study used an alcohol-based spray, so the elevated blood alcohol level could have been the result of inhalation rather than dermal absorption (9).
Keep in mind that this only applies for intact ADULT skin. Damaged or infantile skin isn’t nearly as protective as healthy mature skin. Topical application on newborns can lead to ethanol poisoning and even death (10).
Now, the concentrations of ethanol (70%-99.9%) and the lengths of exposure (1-9 hours) used were significantly higher and longer than what we’d encounter in cosmetic products. So really, there’s no need for adult consumers to worry about systemic absorption of topically-applied ethanol, and the risk for children is low, but should still be avoided.
I would also not recommend those of you with oily skin types to use ethanol chronically in an attempt to dry out your skin. This is because your skin will respond in a homeostatic way, by attempting to repair the damaged epidermal barrier every time it’s dried out by the ethanol.
The skin will be in a vicious cycle; a constant flux between oily and dry, which can lead to very frustrating combination skin that’s flaky and dry on the surface, but oily underneath. The skin uses transepidermal water loss (TEWL), amongst other things, as a marker to gauge lipid synthesis (epidermal homeostasis) (5).
Ethanol increases the penetration ability of other skin care ingredients. This can once again be a positive or negative attribute. For example, it can be positive in the sense that it enhances the penetration of L-ascorbic acid or vitamin C, which can translate to more collagen production. However, it can be negative in the sense that it enhances the penetration of more dangerous chemicals that everyday consumers are unaware.
For example, in my routine review for Emma, I warned her about using products that contained the preservative Bronopol, which has been shown to form nitrosamines. For any science buffs interested, Bronopol decomposes in water and forms bromoethanol, which will react with any secondary amides and amines, such as those present in the commonly-used chelator Disodium EDTA, to form nitrosamines (6). Nitrosamine is carcinogenic and should therefore, be avoided. I’m not trying to scare anyone, unlike those who are more alarmist against parabens, because unlike those claims, the amounts that can form in skin care products are up to tens of parts per billion, which are significant enough to be considered toxic by various regulating agencies. That’s why this ingredient is rarely used in cosmetic products anymore, at least in the United States. Now, throw ethanol into the mix, and you’re looking at even higher amounts of systemic absorption.
Recently, on my Twitter and Facebook, I’ve been raving about the new Lancôme Teint Idole 24H foundation. Because I’m such a fan of Paula Begoun, one of my readers asked me why I was recommending this product when Paula herself gave it a bad review. She gave a bad review because of the high amounts of ethanol present and the fact that it doesn’t contain any UVA protection.
Well, as all of you should know by now, the ethanol present in the foundation will help the vehicular base of your sunscreen and anything else evaporate more easily, which will translate to better coverage and a longer wear-time!
Why would need a sunscreen when this already provides SPF? Paula is right that the foundation doesn’t contain UVA protection. However, EVEN IF IT DID it still wouldn’t provide adequate protection. That’s because the amount you’d have to apply to achieve the labeled SPF rating is much larger than the typical 1-2 pumps used.
So unless you want someone to stick a candle into your (birthday) cake face, you need a separate SPF product anyways! So for those of you with oily skin, which is the skin type that this foundation is targeted towards, the alcohol will “compress” the layers of product into something more long-lasting.
Overall, while ethanol is an adept penetration enhancer, there are other ingredients that function similarly, without the potential drawbacks. For example, most of you know that Nicki has a perennial love affair with the Skinceuticals C E Ferulic Serum ($123.97, Amazon.com)! Instead of ethanol, it uses ethoxydiglycol as the main solvent and penetration enhancer. Ethoxydiglycol is similar to ethanol except that it has a longer carbon chain, which allows it to retain some of the chemical properties of ethanol, without being as potent. (For science buffs: ethoxydiglycol retains the hygroscopy and volatility of ethanol).
The main point to take away is that, though ethanol dries the skin out, it doesn’t directly cause anything like oxidation or the inhibition of collagen production. Ethanol should be used to dry out layers of product, rather than dry out layers of the skin. Even those with very oily skin types should avoid direct application of ethanol to the skin. There are other ingredients that can be used to keep oily skin at bay, such as salicyclic acid and prescription-strength retinoic acid.
My final recommendation when it comes to ethanol in skin care products is to use it in its most harmless way: to help those with oilier skin types achieve longer lasting makeup. I wouldn’t recommend using ethanol-containing skin care that comes in direct contact with the skin. Just because ethanol is safe, doesn’t mean it should be desired. I reiterate, there are similarly-functioning ingredients that aren’t as drying. As always, weigh the pros against the cons!
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