Stearic Acid

From baby lotion and sunscreen to moisturizer and soap, stearic acid is used in a variety of personal care products we use every day. Learn about this skin softening ingredient, and how its many uses make it a versatile component of so many natural formulas.

• Derived from: Coconut
• Pronunciation: (\stē-ˌar-ik\ˈa-səd\)
• Type: Naturally-derived

What is Stearic Acid?

Stearic acid, chemically represented as C18H36O2, is a long-chain saturated fatty acid that occurs naturally in various animal and plant fats, predominantly derived from coconut or palm oil. This fatty acid appears as a white, waxy, solid substance that is often crystalline in nature and exhibits a mild odor.

The ingredient is a major component of cocoa and shea butter, which are widely used in the cosmetic and food industries. Stearic acid's hydrophobic nature and high melting point contribute to the stability, texture, and spreadability of these natural butters, making them highly valued in skincare formulations and chocolate production.

How is Stearic Acid Made?

The production of the ingredient involves the hydrolysis of common animal and vegetable fats and oils, followed by fractionation (distillation or crystallization) of the resulting fatty acids. Pressing methods separate the liquid unsaturated fatty acids from the solid saturated fatty acids.

The ingredient used in cosmetics usually undergoes two or three pressing processes, resulting in different concentrations. Cosmetic-grade stearic acids are often mixtures of fatty acids, depending on their manufacturing and source (they are often combined with palmitic acid). There are several grades of the ingredient available commercially.

Benefits of Stearic Acid for Skin

There’s a reason the ingredient is found in so many cosmetics: it’s known for its skin smoothing abilities. Learn more about its many benefits below.

• Moisture Retention and Skin Aging

Stearic acid's emollient properties help lock in moisture, keeping the skin hydrated and improving its overall appearance. This can contribute to a more youthful-looking complexion and may help reduce the signs of aging.

• Reducing Inflammation

Stearic acid may possess anti-inflammatory properties, helping to soothe irritated skin and reduce redness.

• Treatment of Skin Conditions

While not a primary treatment for skin conditions like eczema, the ingredient's moisturizing and anti-inflammatory properties can provide relief and support in managing symptoms when used in conjunction with other treatments.

• Skin Barrier Optimization

By helping to maintain the skin's natural moisture barrier, the ingredient can protect the skin from environmental stressors and irritants.

• Mild Surfactant

As a mild surfactant, stearic acid can help cleanse the skin without stripping it of its natural oils.

• Emulsifier

In skincare formulations, the ingredient acts as an emulsifier, ensuring that oil and water components blend together seamlessly for a smooth, even application.

• Texture and Prevention of Separation

Stearic acid contributes to the consistency and texture of skincare products, preventing them from separating or becoming unstable.

Potential Negative Side Effects of Stearic Acid

• Low: Cancer
• Low: Development and Reproductive Toxicity 
• Moderate: Allergies 
• Moderate: Use Restrictions 

With any product, it’s important to research its formula and determine the ingredients’ safety for your specific needs and concerns. Here are some potential negative side effects related to the ingredient.

• Safe Concentration

The safe concentration of stearic acid in topical products depends on the specific formulation and intended use. The ingredient has been deemed safe for use in cosmetics, but it is essential to follow manufacturer guidelines and consult with a healthcare professional if you have concerns.

• Skin Irritation

Some individuals may experience skin irritation, such as redness or itching, when using products containing the ingredient in concentrations of over 70%. These reactions are typically mild and subside after discontinuing the use of the product.

• Eye Irritation and Damage

Stearic acid can cause eye irritation or damage if it comes into direct contact with the eyes. It is crucial to avoid applying products containing the ingredient near the eye area and to wash your hands thoroughly after handling such products.

• Allergenicity

Some individuals may have an allergic reaction to stearic acid, resulting in symptoms such as redness, itching, or rashes. These reactions usually clear up within a few days to a week after discontinuing the use of the product containing the ingredient. If you have a history of skin allergies or sensitivities, it is advisable to consult a dermatologist before using products containing stearic acid and perform a patch test on a small area of skin.

Stearic Acid Safety: Addressing Common Concerns

The ingredient is generally considered safe for use in cosmetics and personal care products. However, it is crucial to address common concerns related to its safety, such as cancer, allergies and immunotoxicity, developmental and reproductive toxicity, and any use restrictions.

• Cancer

There is no evidence to suggest that stearic acid is carcinogenic, and no studies have linked this ingredient to an increased risk of cancer.

• Allergies and Immunotoxicity

While the ingredient is generally well-tolerated, some individuals may experience allergic reactions or sensitivities to this ingredient. Symptoms may include redness, itching, or rashes on the skin. In most cases, these reactions clear up within a few days to a week after discontinuing the use of the product containing stearic acid. If you have a history of skin allergies or sensitivities, it is advisable to consult a dermatologist before using products containing the ingredient and perform a patch test on a small area of skin.

• Use Restrictions

While stearic acid is generally safe for use in cosmetics and personal care products, it is essential to follow any guidelines or restrictions provided by regulatory authorities, product manufacturers, or dermatologists. If you have specific concerns or pre-existing skin conditions, it is always best to consult with a healthcare professional before incorporating new products into your skincare routine. 

Commonly Found Personal Care Products & Ingredients Containing Stearic Acid

Stearic acid is a versatile ingredient found in a wide range of products, both in the personal care industry and beyond. Its properties as an emulsifier, emollient, and lubricant make it a popular choice for various applications.

• Moisturizers

The ingredient helps lock in moisture and maintain skin hydration, making it a key component in many moisturizing creams, lotions, and facial products.

• Sunscreens

It is used in sunscreen formulations to improve the product's texture and stability while offering additional moisturizing benefits.

• Makeup

Stearic acid can be found in various makeup products, such as foundations, powders, and mascaras, where it helps maintain the product's consistency, ensuring a smooth application.

• Soaps

As a mild surfactant, the ingredient is often used in soap formulations, helping to cleanse the skin without stripping away its natural oils.

• Baby Lotions

Stearic acid's gentle, moisturizing properties make it a popular choice for baby lotion formulations, providing hydration and protection for delicate skin.

• Laundry Products

In laundry detergents and fabric softeners, the ingredient acts as a surfactant and softening agent, helping to remove dirt and grime while keeping fabrics soft and fresh.

Stearic Acid Safety

Whole Foods has deemed the ingredient acceptable in its body care quality standards, and studies show the ingredient is not a skin irritant.[12,13,14,15,16,17] The Cosmetics Ingredient Review has deemed stearic acid as safe for use in cosmetics.[18]

Environmental Safety and Sustainability of Stearic Acid

How safe is the ingredient for our planet? From its biodegradability to its impact on aquatic life, learn more abouts its effect on the environment.

• Biodegradability

Stearic acid is considered readily biodegradable, meaning that it can break down relatively quickly in the environment. Microorganisms, such as bacteria, play a significant role in breaking down the ingredient into simpler compounds, eventually converting it into carbon dioxide, water, and other natural elements. This process helps reduce the potential for the fatty acid to accumulate in the environment, thus limiting its ecological impact.

• Aquatic Life Safety

Although the ingredient is biodegradable, it can be harmful to aquatic life if released into water bodies in large quantities. High concentrations of stearic acid may cause oxygen depletion in water, leading to adverse effects on fish and other aquatic organisms. However, given its biodegradable nature and limited solubility in water, the risk of the ingredient causing long-term harm to aquatic life is relatively low when released in controlled amounts.

• Energy Consumption and Sustainability

The production of the ingredient primarily relies on extracting it from plant or animal fats through processes like hydrolysis, followed by purification and separation techniques. While these processes may consume energy, they are relatively energy-efficient compared to the production of synthetic chemicals.

Additionally, the ingredient's sourcing from renewable resources like coconut or palm oil makes it a more sustainable option than non-renewable, petroleum-derived alternatives. However, it is important to note that the cultivation of palm oil, a significant source of the ingredient, has raised environmental concerns due to deforestation and habitat destruction. Ensuring the use of sustainable palm oil is vital to minimize the environmental impact of stearic acid production. 

Discover the Benefits of Stearic Acid with Puracy

Whether you're looking to lock in moisture or cleanse your skin, you can discover stearic acid in our plant-powered personal care essentials, such as our Natural Body Wash or Natural Shampoo & Conditioner. Experience the benefits of this versatile ingredient for yourself in some of Puracy's effective and gentle formulas that take on the toughest dirt and grime, while still being safe for the most sensitive skin.

[1] American Cleaning Institute
[2] U.S. National Library of Medicine
[3] U.S. National Library of Medicine
[4] Personal Care Council
[5] Personal Care Council
[6] U.S. National Library of Medicine
[7] Personal Care Council
[8] U.S. National Library of Medicine
[9] Environmental Working Group

[10] U.S. National Library of Medicine
[11] U.S. National Library of Medicine
[12] Whole Foods Market
[13] Butcher, E.O. (1951). “The effects of application of various substances in the epidermis of the rat.” Journal of Investigative Dermatology. 16, 88
[14] CTFA. (Aug. 14, 1974). Submission of unpublished data. (3-3-10). Safety evaluation of 2.0 percent Stearic Acid in 01 B/62568-)(6020). Four-week subacute dermal toxicity study in rabbits
[15] CTFA. (Aug. 14, 1974). Submission of unpublished data (3-3-16). Four-week subacute dermal toxicity study in rabbits: 2.0 percent Stearic Acid
[16] CTFA. (July 11, 1980) Submission of unpublished data. (3-3-21). Study project 0135. The safety evaluation of two sun protection products and one facial skin care product. Thirteen-week subchronic dermal toxicity study in albino female rats on 5.0 percent Stearic Acid
[17] CTFA. (Aug. 18, 1982). Submission of unpublished data. (3-3-15). Study project 0191. The safety evaluation of three make-up products: 2.4 percent Stearic Acid in 036/18218-12. Thirteen-week subchronic dermal toxicity study using female albino rats
[18] Personal Care Council