What is stearic acid used for? According to the Skin Store website, it’s a very common additive used in the manufacturing of more than 3,200 skin, soap and hair care products, such as soaps, shampoos and household cleaners.
It has properties that make it a natural cleansing agent, capable of helping remove excess sebum (oil), dirt and bacteria from skin, hair and other surfaces. It’s also an emulsifier, emollient and lubricant.
What Is Stearic Acid? Where Is It Found?
Stearic acid (SA), sometimes also called octadecanoic acid, is a saturated long-chain fatty acid. It’s present in humans, animals and some plants.
It appears as a waxy, yellow-white, solid substance.
Stearic acid uses include:
- Making soap and cleansers (one of the most common ways it’s used worldwide)
- Improving the efficacy and texture of cleansers, lotions and skin care/hair products, including shampoo and conditioner
- Making cosmetics/makeup
- Stabilizing the texture of shaving creams and lubricants
- Creating detergents, house cleaners and textile softeners
- Forming and softening plastics
- Making candles
- Making chewing gum
- Making supplements/tablets
Stearic acid’s structure (being an 18-carbon chain fatty acid) allows it to help improve the texture and consistency of other products. It can help make skin/hair/household products solid and improve the ability of them to to mix with water (which is usually difficult since oil/water do not combine well).
Where It’s Found:
Is stearic acid a natural ingredient?
Yes, which is why it’s found in many natural skin care/beauty products in place of chemical ingredients.
SA is found naturally in animal fat, especially pork fat, and also certain plants that contain fat/oil. These sources are heated and pressurized in order to isolate and remove stearic acid.
It then goes a process that involves distillation, steaming and cooling in order to create a finished product of concentrated SA, which is usually a waxy substance.
Additionally, it is found in some supplements, including magnesium stearate, which is a combination of stearic acid and the mineral magnesium.
Although the consumption of commercially hydrogenated fats is not recommended, since these are found in packaged foods that are linked to various health problems, SA is also used to create these fats.
You’ll find stearic acid listed on product labels under several different names, some which include:
- Octadecanoic acid
- Century 1240
- Cetylacetic acid
- Emersol 120 or 132 or 150
- Formula 300
- Glycon DP
Because SA is sometimes sourced from animals, it’s not always suitable for vegans or found in vegan cosmetics. For example, the Environmental Working Group and PETA list it as a “substance of animal origin” since it’s derived from rendered fat of farm animals.
Certain types that are obtained from plants, however, such as coconut, can be used in vegan/animal-free products.
Stearic Acid Uses and Benefits
1. Natural Skin Cleanser and Lubricant
What does stearic acid do to the skin?
It helps remove dirt, bacteria and other substances from the surface of skin. SA also gives a creamy and “waxy” feel to body care products.
It can lock in moisture and dryness by protecting the skin’s surface against water loss and creating a waxy protective barrier, as explained by the Derm Review. In fact, the presence of SA is partially what gives moisturizing products like cocoa butter and shea butter their thicker consistency and lubricating effects.
Does stearic acid clog pores?
Even though it is a fatty acid, it shouldn’t. It fact, it can help cleanse pores of excess oil and substances that can build up to form blackheads/whiteheads.
This is due to its ability to degrease and works thanks to its emulsifying effects on oils/lipids.
Is stearic acid harmful to skin if your skin tends to be sensitive?
It’s considered safe for most people and easy to tolerate, even for aged skin and when worn in the sun. However, there’s always a chance that someone can have a sensitivity, so start by using SA-containing products sparingly at first to test your reaction.
2. Surfactant Agent
A surfactant, or surface active agent, reduces tension between two substances. One of the most important benefits of stearic acid is its ability to help make water and oil mix together more easily in products.
Is stearic acid soluble in water?
It is fairly insoluble in water but becomes somewhat soluble in alcohol. More importantly, it helps lower the surface tension of oil, allowing it to combine better with water so together the two an be used to thoroughly wash anyway microbes from skin, hair, etc. As a surfactant, it can also attract oil, dirt and other impurities that accumulate on your skin and on other surfaces.
3. Natural Emulsifier
SA is used to help prevent ingredients in different types of products/formulas from separating. It’s used to thicken/harden formulas and bind together ingredients so they don’t wind up separating into liquid and oily layers.
This prolongs how long products like lotions, cosmetics, conditioners, etc., stay stable and useable.
You’ll also find stearic acid in supplements, such as magnesium stearate, for this reason. It’s added to keep the solid ingredients from falling apart and aid in the proper release of active ingredient after someone swallows the supplement.
Stearic Acid Foods and Products
When you eat foods that contain fat there’s a good chance you’re consuming stearic acid in small amounts. It’s a saturated fat with 18 carbon atoms and relatively common in the human diet, according to research.
While it’s used to make some unhealthy processed fats, in its natural form it can have slightly positive or neutral effects on blood lipid profiles.
Stearic acid food sources include:
- Lard and tallow (rendered fats from cows and pigs, which contain up to 30 percent stearic acid)
- Fatty meats, such as pork or beef — an article published in the American Journal of Nutrition states that beef is the most common source of dietary stearic acid in the United States, since its roughly 19 percent stearic acid
- Coconut oil
- Palm kernel oil
- Chocolate (cocoa butter)
Animal fats are higher in stearic acid than most plants that contain oils. The exceptions to this rule are cocoa butter and shea butter, two plant-derived products that are both relatively concentrated sources of SA.
SA is also found in supplements, including magnesium stearate, which is usually derived from palm oil. Because of its waxy texture, SA acts as an emulsifier of ingredients used in supplements and as a lubricant to fill capsules when dry powdered ingredients are used.
It can help prevent capsules/tablets from breaking apart and ingredients from separating.
You can use SA at home to make your own lotions and soaps. Most recipes will call for water, oils and an emulsifier (such as SA) to create a stable and smooth product.
If you’d like to purchase SA to use in DIY recipes at home, you’ll often find a mixture of stearic and palmitic acids. Purified stearic acid is available but less commonly sold.
If you’re looking for a plant-based/vegan source of SA, make sure to buy a product made from palm or cocoa.
When making lotions and creams, it’s recommended you use around 2 percent to 5 percent stearic acid in order to help your ingredients blend together and go on smoothly. The more you use, the thicker your product will be.
Try stearic acid in a variety of recipes that use beneficial ingredients, such as:
You can combine SA with other emulsifiers or waxes in cream/lotion recipes if you want a very smooth finished product. Emulsifiers will bind together water and oil to create lotion that will not separate.
Below is a basic homemade lotion recipe provided by the Soap Queen website:
- 70 percent to 80 percent distilled water
- 3 percent to 5 percent stearic acid (or other co-emulsifier)
- 3 percent to 6 percent emulsifying wax (or other emulsifier)
- Your choice of oils and butters, such as shea, coconut oil, etc.
You can also add stearic acid to these DIY beauty/skin care recipes:
- Homemade Lotion With Frankincense and Lavender Oils
- Homemade Hand Soap
- Lavender and Rosemary Hair Detangler
- Homemade Conditioner
Risks and Side Effects
Is stearic acid safe?
The U.S Food and Drug Administration (FDA) considers stearic acid safe for both consumption as a food additive and for topical use in skin care products in limited quantities.
According to the Cosmetics Info website, studies have shown that SA is non-photosensitising (doesn’t make skin prone to sunburns), not irritating to the eyes and non-carcinogenic.
Most people have a low risk of experiencing stearic acid side effects when using it on their skin, considering it’s a natural fatty acid found in humans. However, some people with sensitive skin may have experience mild reactions.
Is stearic acid ever harmful, such as for heart health?
Although it is fatty substance, SA is not linked to cardiovascular problems and is even the immediate precursor of oleic acid, an important fatty acid found in heart-healthy olive oil. A number of studies have found that effects of SA on cardiovascular health are more favorable than those of trans monounsaturated fatty acids.
SA has even been shown to help lower LDL cholesterol and decrease the ratio of total to HDL cholesterol slightly.
- Stearic acid is a natural fatty acid that appears as a waxy, yellow-white substance. It’s sourced most often from animal fats, including tallow and lard, or cocoa butter and shea butter.
- What is stearic acid used for? It’s a common additive in soaps, cleaners, lotions and hair care products, as well as house cleaners, candles and plastics.
- Benefits include naturally cleansing skin, lubricating skin and hair, and emulsifying ingredients in products and supplements.
- Is stearic acid safe? Stearic acid side effects are rare, as this fatty acid is naturally occurring inside the human body.
- When consumed from food sources it doesn’t seem harmful to heart health and may even have benefits, such as for cholesterol levels.
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