Stearic acid is an 18-carbon chain saturated fatty acid that is widely used in a broad range of skincare and cosmetic products. It's main application often revolves around supporting the original scent/fragrance of the product as well improving the spreadability and texture. It is also believed to increase/improve the skin's moisture content which has an overall positive impact on the texture and tone.
Also known as octadecanoic (due to the 18 carbon atoms in its chemical structure) acid, stearic acid is ordinarily derived from vegetable or animal fats and oils. Nonetheless, animal fat and oils are generally considered to be richer sources of stearic acid than their vegetable-derived counterparts. But that does not mean that it is impossible to come across stearic acid derived from purely vegan sources. A good example is shea or cocoa butter that is thought to contain as high as 45% stearic acid content.
So, is stearic acid good or bad? From a general point of view, stearic acid has some important dermatological significance. Chief among them is that it can improve the texture, scent, and spreadability of a cream's formulation. It's presence in your favorite skincare product should not be a cause of alarm or raise any safety concerns whatsoever.
What Is Stearic Acid?
Stearic acid is an inert (passive) ingredient that is considered some form of a unicorn in dermatological circles. It's a surfactant, emollient and emulsifier that is mainly used to improve a product's formulation. Unlike a majority of active ingredients, stearic acid is dermatological well-tolerated even by those with dry and sensitive skin. In fact, part of the reason it is incorporated in the formulation of most products is because of its ability to temper extreme side effects of active ingredients such as retinol or kojic acid.
Now, at this juncture you could be bombarded with pressing questions such as, 'Where does stearic acid come from?' or 'What is stearic acid made of?' Well, the name 'stearic acid' does not exactly do this compound any justice, since it's a bit of a misnomer. By the traditional definition of the term 'acid' and the overall sense of it, the stearic acid structure is hardly one. It's primarily a long-chain and saturated fatty acid that occurs naturally in a number of plant and animal fats. That said, it can also be synthetically derived when a manufacturer needs a balanced and controlled formulation to work with. In a way, stearic acid is more or less a moisturizing fat that is used to add a bit of body to a cosmetic product.
Stearic Acid Uses
Although stearic acid is used mainly for product formulation, it does not mean that it is bereft of particular skincare benefits and uses of its own. And this includes the following stearic acid uses:
1. Surface-Active Agent
There's no denying that stearic acid makes an excellent surface-active agent, also known as a surfactant. Functionally speaking, it works to reduce the surface tension between two ingredients allowing them to mix or combine better and more evenly.
Additionally, a surfactant is used to emulsify and degrease fats and oils while at the same time suspending dirt particles, making it easier to wash them off. And this is possible due to the fact that one end of stearic acid is attracted to water molecules (hydrophilic end) while the other one has an affinity for oil (hydrophobic end). This way, the surfactant effect of stearic acid when used in a cleanser, body wash or soap makes it incredibly easy to get rid of impurities, grime and dirt.
2. Thicker and Hardener
Another property of this octadecanoic acid is its unmatched ability to work as a hardener or thickener. It helps harden the product in which it is employed allowing it to retain its form/shape and allow for longevity. It's no wonder it is employed in things like plastics, candles, soaps, oil pastels et cetera.
Stearic acid is also a renowned emulsifier. Conventionally, an emulsifier is needed for formulating products that have both oil and water components and this octadecanoic acid really excels at it. Again, the duo-polar nature of stearic acid comes into play here and prevents the separation of oil and water-based ingredients. You see, the water-loving end (hydrophilic head) binds firmly to the water-based ingredients while the oil-loving tail (hydrophobic) attaches to the oil based one. This, in one way or another, prevents the physical separation of the otherwise unmixable ingredients thereby improving the longevity, stability and overall consistency of the skin care product.
Stearic Acid In Skin Care
Apart from the already discussed industrial uses, there are several ways stearic acid can benefit your skin. Here is a quick premise to that.
1. It's a Decent Moisturizing Emollient
The main objective many manufacturers employ stearic acid in skin care stems from the fact that it is a proper moisturizing ingredient, more specifically an emollient. In simpler language, it means that it works by smoothing and softening the skin. Other good examples of emollients include ceramides, squalane and jojoba oil.
2. Bolsters and Strengthens the Skin Barrier
Apparently, it appears that stearic acid is also a crucial component of one's skin barrier, more specifically, the outermost layer that is responsible for looking natural moisture in while preventing the entry of irritants. And being a fatty acid, it goes without saying that stearic acid skin care benefits encompass a broad range of applications especially those that are associated with hydration and even aging. There's also plenty of anecdotal evidence that points to this passive ingredient being helpful in lessening itchiness or flakiness associated with debilitating and pertinacious skin conditions such as psoriasis.
3. Cleanses the Skin without Stripping Off its Natural Oils
When used as a surfactant, stearic acid can get rid of grime and oils from the surface of the skin while still imparting its unique moisturizing effects to the epidermis. Additionally, its one of the few gentle cleansers that does not strip off one's natural oils when washing off dirt and oily irritants from the surface. This makes it an ideal cleanser for those looking for an effective cleanser that won't exacerbate their skin woes by irritating or drying it out.
In Closing - How to Use It
While you may be conversant with the basics of what is stearic acid in skin care, most people are not usually familiar with the practical ways of using this amazing ingredient which is an integral part of skin care. Speaking of which, there are several things that you ought to be aware of, as far as this goes.
First, there is a reason stearic acid is used for formulation reasons; it is not an active ingredient. It's not something that you need to go and specifically look out for, or source single-handedly. Instead, you would want to make use of skin care products that employ stearic acid as part of their formulation. Perfect examples of this are gems such as Papaya Kojic Acid Glutathione by Bloommy and this Collagen Retinol Cream. Actually, since it is basically a fatty acid which mixes incredibly well with other closely-related lipids, it is easy to see the reasoning behind its inclusion in this retinol cream - It aids in counteracting the potentially irritating and drying side effects of vitamin A by bolstering and fortifying the skin's barrier.