What is stearic acid?
Stearic acid is a saturated fatty acid with an 18 carbon chain used in a wide variety of cosmetic and skin care products. Stearic acid is mainly used to enhance the fragrance of the product and to improve texture and spreadability. Stearic acid also has an added benefit as it helps improve the skin’s moisture levels.
Stearic acid, also known as octadecanoic acid, can be obtained from both animal and vegetable fats and oils. However, fats and oils that are rich in stearic acid are more commonly found in animal fats. up to 30%, than in vegetable fat, typically less than 5%. Depending on the source of the stearic acid, it may be a vegan ingredient, especially if it’s made from both cocoa or Shea butter which have a higher stearic acid content of 28 to 45% or
the breakdown
Stearic acid
the good: Helps to improve the fragrance, texture and spreadability of a formulation. Stearic acid also has an added benefit as it helps improve the skin’s moisture levels.
not that good: Depending on the source of the stearic acid, it can be vegan or animal origin.
For whom is that? All skin types except those who have an identified allergy.
Synergetic ingredients: Works well with most ingredients.
Keep an eye on: If you’re looking to use a vegan product, check out what source of stearic acid the brand uses.
What is the difference between acids and fatty acids?
Although the name includes acid, fatty acids are very different from what you would generally call acids. Fatty acids are the building blocks for fats and oils. Unlike acids, they tend to be moisturizing and gentle on the skin.
What are the benefits of stearic acid in a formulation?
Stearic acid acts primarily as a surfactant, emulsifier, and thickener when added to cosmetic and skin care products.
Surfactant
Surfactant is the abbreviation for surface-active agent. Surfactants are compounds that lower the surface tension between two substances in order to mix them or to wet the skin evenly.
Another task of surfactants is to degrease and emulsify oils and fats and to float and wash off dirt. This is possible because one end of the surfactant molecule is attracted to water while the other end is attracted to oil. For example, surfactants attract and wash away oil, dirt, and other impurities that have built up on your skin over the course of the day. Because of these properties, stearic acid is found in many different detergents and body wash products.
Emulsifier
Stearic acid also acts as a Emulsifier. An emulsifier is required for products that contain both water and oil components. Water and oil based ingredients tend to separate in the formulation. Emulsifiers help keep them mixed and prevent ingredients from splitting or separating. This helps stabilize and improve the longevity of your product.
As an emulsifier, stearic acid consists of a water-loving hydrophilic head and an oil-loving hydrophobic tail. The hydrophilic head is attracted to the water-based ingredients and the hydrophobic tail to the oil-based ingredients, pulling them together and preventing this separation.
texture
Another property of stearic acid is its ability to act as a thickener or hardener. For this reason, stearic acid is added to soaps, candles, plastics, oil pastels, etc., for example. It helps harden the product and keep it in shape.
How does stearic acid affect the skin?
cleaning
As a surfactant, stearic acid helps wash away excess oil and dirt from the skin. Stearic acid attracts dirt and oils and allows them to be washed off the skin.
Skin barrier
Stearic acid has been shown to protect The skin’s natural barrier against water loss and support the protective barrier of the skin. The skin’s natural barrier is made up of the first layers of the skin and the natural oils that it produces. This barrier protects the skin from allergens, bacteria and from water loss to the air and the environment. If the skin barrier is damaged or disrupted by the use of aggressive products, aging, the environment or skin diseases such as eczema or dermatitis, the skin can lose this protective capacity.
Stearic acid is an important part of the skin’s barrier and is widely used in skin care products. In formulations, it can support the healthy functioning of the skin barrier and potentially help improve hydration and sensitivity. It is important to note that this benefit has not been well researched.
Is stearic acid vegan?
Stearic acid can be a vegan ingredient, depending on the source from which the ingredient is obtained. It can be derived from cocoa, Shea butter, animal fat and vegetable fats.
When looking for a vegan product, always check with the brand about what source of stearic acid they are using.
Is Stearic Acid Safe?
the US Food and Drug Administration adds stearic acid to its list of Direct Food Additives Generally Recognized as Safe (GRAS). the Expert panel for the review of cosmetic ingredients, a group responsible for evaluating the safety of skin care and cosmetic ingredients, evaluated the scientific data and concluded that stearic acid is safe for use in cosmetic products.
References:
Lin, T, Zhong, L, & Santiago, J, 2017. ‘Anti-inflammatory and Skin Barrier Repair Effects of topical Application of Some Plant Oils’, International Journal of Molecular Sciences, 19 (1), 70.
Cosmetic Ingredient Review, 1987. Final report on the safety evaluation of oleic acid, lauric acid, palmitic acid, myristic acid, and stearic acid, International Journal of Toxicology.
