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Who doesn’t love the rich, velvety feel of soap on the skin? Yet, how many of you actually know what ingredient is responsible for that sensation? Stearic acid is a fatty acid found in many cosmetics due to its numerous attributes.
Take a look at what stearic acid is, its function in skincare and its natural sources.
Table of Contents
- What is Stearic Acid?
- Stearic Acid’s Function in Skincare Formulations
- Stearic Acid Skin Benefits
- Primary Plant Sources of Stearic Acid
- Who Should Use It?
- How to Incorporate Stearic Acid Into Your Skincare?
- Summary
- F&Q
- References
What is Stearic Acid?
Stearic acid, also known as octadecanoic acid, is a naturally occurring saturated 18-carbon chain fatty acid. It is found in the stratum corneum (upper layer of our skin) and many plants and animal tissues. Extracted stearic acid is a white solid substance with a mild odour (1).
Stearic Acid’s Function in Skincare Formulations
Predominantly, stearic acid acts as a thickener, surfactant and emulsifier in skin care formulations (2). It improves the texture, scent and spreadability of the final product. Furthermore, stearic acid acts as a cleanser helping to remove makeup, grime and excess oil from the skin. Hence, it is used in a variety of skincare products and cosmetics.
Emulsifier
The primary role of an emulsifier is to enable ingredients that would typically not mix, such as oil and water, to create a stable mixture, and emulsion (3). Stearic acid acts as an emulsifier that stabilises the mix of water and oil due to its water-loving and oil-loving properties – it can interact with both. It also prolongs the products’ shelf life by preventing the emulsion from splitting. Emulsifiers are often used in skincare products, such as lotions, foams and creams.
Surfactant
In addition, stearic acid is also used in cleansing products where it acts as a mild surfactant that helps to cleanse and hydrate the skin. Surfactants work by lowering the surface tension between two substances, allowing them to mix (4). Hence it is added to cleansing products to help remove oil and grease from the skin by enabling soap particles to attach to grime.
Thickener
Cosmetic products such as lotion, cream and hair conditioner are essentially water-based. In skincare, stearic acid is regarded as a thickener and stabiliser thanks to its ability to increase the viscosity of water-based products. It can help create silky emulsions that are well adapted to the needs of the skin. In effect, it helps make the final product smooth, creamy and spreadable.
Stearic Acid Skin Benefits
Who doesn’t want to feel good in their skin? Hence, we are naturally conscious of the ingredients we apply to our skin and their effects. Stearic acid is one of these ingredients. It is a highly effective skin care ingredient that is used wildly in the cosmetic industry. So, what benefits are offered by stearic acid?
It is naturally moisturising
Natural emollients, such as stearic acid, are used in skincare to protect the skin from environmental damage and improve the skin’s hydration and condition. As it occurs in the skin, naturally, it penetrates our skin quickly. Stearic acid helps the skin retain its moisture by creating a waxy, protective barrier, locking the water, and preventing dryness – giving skin a nice supple feel.
Preserves the skin’s natural barrier
When you think of the stratum corneum, I would like you to imagine brick and mortar. The bricks are your corneocytes, and the mortar is a mixture of lipids (the mortar), including ceramides, cholesterol, and fatty acids. This ‘mortar’ helps keep the corneocytes together.
Stearic acid’s most important role is that it helps to preserve the skin barrier by keeping the lipid ‘mortar’ mixture intact and preventing the water loss that follows. In addition, this barrier keeps harmful bacteria and other microorganisms from entering the skin, which can cause inflammation and infection.
It is naturally cleansing
Surfactants, such as stearic acid, are used in skincare to remove grime, pollutants and makeup from your skin, acting as a dirt magnet. However, regular cleansing can disrupt a natural skin barrier by removing not only the dirt but also extracting our skin lipids (the ‘mortar’ we just talked about), causing dryness and irritation.
Unlike other surfactants, stearic acid is gentle on the skin. Therefore, incorporating it into the cleansers helps
- remove dirt
- minimise the removal of fatty acids from the skin
- replenish lost fatty acids in the skin after cleaning – preserving the skin barrier (5).
Primary Plant Sources of Stearic Acid
In oils and butter, stearic acid is common in small amounts. However, some of the oils, including babassu oil (1%-11%), illipe butter (40%-48%), kokum butter (52%-65%), shorea (sal) butter (40%-50%), mango butter (35%-45%), neem oil (6%-24)%), shea butter (36%-47%), and cocoa butter (31%-39%) are abundant in stearic acid. As many of these oils are widely used in cosmetic formulations – from soap to skin cream and lotion, stearic acid plays a vital part in nurturing our skin.
Babassu oil
Lightweight with a cooling effect on the skin, babassu oil is a good source of tocopherols – antioxidants well known for their anti-inflammatory effect. It is trendy in hair care where it can help manage frizz, moisturise the hair, and prevent breakage, leaving hair soft and shiny.
Illipe butter
Illipe butter is known for its moisturising effect and its ability to restore skin elasticity. Abundant in vitamin A and E and deeply moisturising, this exotic butter has been made by indigenous Borneo people for centuries. Instrumental in treating dry, mature skin, after-sun care, sores, and dry hair, it can be used in a range of skincare products, from balms to hair conditioners.
Kokum butter
The antioxidant and moisturising properties of kokum butter make it an ideal emollient for damaged skin. It can help reduce dryness, reduce inflammation but also restore skin elasticity. Although the butter is rather hard, it melts on contact with the skin and can be used to thicken lotions, creams and other cosmetics.
Shorea (Sal) butter
Mild and naturally pliable, sal butter is an excellent moisturiser that provides long-lasting hydration. Its high content of stearic acid also makes it an ideal ingredient for dry skin formulations.
Mango butter
Abundant in vitamin A, C and E, essential fatty acids (omega 6) and antioxidants, mango butter is a popular emollient in treating dry skin conditions such as eczema and psoriasis. It can help reduce inflammation and itchiness associated with these conditions. In addition, it is popular in skincare for its ability to reduce the appearance of fine lines and wrinkles.
Neem oil
The anti-bacterial, antiseptic, anti-inflamatory and antioxidant properties make neem oil is a popular ingredient in skincare and haircare products. In addition, it is preferred in dermatological skincare formulations for its plethora of benefits. Known to reduce wrinkles, increase skin elasticity, revitalise dull skin, and soothe the skin, it is an effective emollient that can prevent moisture loss and protect the skin’s natural barrier.
Shea butter
Abundant in vitamins A and E, shea butter is an excellent moisturiser used in skincare products to smooth, soften and rejuvenate damaged skin. In addition, it is a popular ingredient used to reduce the appearance of scars and stretch marks. Fatty acids in shea butter help protect the cuts and wounds from external threats during the healing process. In addition, its anti-inflammatory properties may help reduce redness and swelling caused by sunburn.
Cocoa butter
Abundant in saturated fatty acids and polyphenols, cocoa is a perfect butter for skin care formulations. Known for its anti-inflammatory and antioxidant properties and priced for its anti-ageing effect, cocoa keeps the skin soft, smooth and moisturised. Thus, it is a perfect choice for dry, itchy skin suffering from dermatitis, eczema or psoriasis.
Who Should Use It?
Well-tolerated by all skin types, stearic acid works for most of us. As a natural surfactant, it can help remove dirt, grime and sebum without disrupting the skin barrier, helping balance the skin while removing impurities. Based on its ability to cleanse, moisturise and preserve the barrier function of the skin, it works for:
– acne-prone and oily skin by cleansing blocked pores from excess sebum and dead skin, building up to form blackheads, causing redness, swelling, and inflammation.
– dry and mature skin by minimising skin dryness and maintaining the moisture barrier function of the skin.
– sensitive skin as it is less likely to cause any irritation. However, if you have sensitive skin, you might like to use products containing stearic acid sparingly to test your reaction at first.
How to Incorporate Stearic Acid Into Your Skincare?
Stearic acid is a common ingredient in lotions, creams, and soaps, so there is a good chance that it is already included in some of the products you are using. So you don’t need to look for it as such. Yet, if you would like to incorporate this fatty acid into your skincare in its natural form, plant oils and butter such as babassu oil, kokum butter, mango butter, neem oil, and shea butter make for a good choice.
Summary
Stearic acid is a natural fatty acid sourced from animal fats or vegetable oils such as cocoa, shea or mango butter. Gentle on the skin, it is commonly used in cosmetics for its cleansing, lubricating, and emulsifying effect.
F&Q
Is stearic acid safe to use?
Stearic acid is considered safe for consumption and topical application by U.S. Food and Drug Administration (6). In topical application, it is well-tolerated by all skin types. However, like any ingredient, it can potentially trigger an allergic reaction.
Is stearic acid vegan?
Not necessarily. Environmental Working Group (7) lists stearic acid as “a substance of animal origin” as it can be sourced from plants and animals. However, stearic acid’s vegan alternative is derived from palm oil, for example. You can find a vegan, sustainably sourced stearic acid at Naissance.
What skincare products use stearic acid in their formulations?
You can find stearic acid in a range of cosmetic formulations such as moisturising creams and lotions, cleansers, body butter, face mask, shampoos, conditioners, shower gels, and soaps.
