Stearic Acid
Saturated fatty acid derived from plant and animal fats. In cosmetics, it functions as an emulsifier, thickener, and co-emollient.
Evidence by route
Topical application
A formulation component with no standalone therapeutic activity. Safety in cosmetic use confirmed by CIR.
- Cosmetic Ingredient Review. Int J Toxicol. 1987;6(3):321-401.
How to read tiers A–F
- DNo data, or very weak or conflicting data
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Dry, Normal, Combination
About this ingredient
Stearic Acid (C18H36O2) is a saturated 18-carbon fatty acid. Sourced from plant fats (cocoa butter, shea, coconut) and animal fats. The skin synthesises it as part of the lipid matrix. Mechanism. In cosmetics it performs three roles: o/w emulsifier (after alkaline neutralisation), cream thickener, co-emollient. Forms liquid-crystalline structures in emulsions and stabilises texture across temperatures. Where applied. Face and body creams, soap, cleansing bars, balms. Concentration 1-10%. In Spain it features in Eucerin, Bioderma, Avène. Evidence base. Free stearic acid is naturally present in the stratum corneum and supports the lipid matrix together with ceramides and cholesterol. Safety. CIR confirmed safety at all concentrations. In some acne-prone patients high leave-on concentrations (>5%) may trigger comedones – Fulton rating 2. Pregnancy and lactation – safe.
Frequently asked questions
Is Stearic Acid safe during pregnancy?
Stearic Acid is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Stearic Acid for?
Stearic Acid suits: dry, normal, combination.
What is Stearic Acid and what does it do in cosmetics?
Saturated fatty acid derived from plant and animal fats.
Is Stearic Acid comedogenic?
On the Fulton scale 2/5 – low comedogenicity. For acne-prone skin, a rating of 3 or higher suggests choosing an alternative.
What's the INCI name for Stearic Acid?
The INCI name is Stearic Acid. It may also appear as: Stearis Acid.
See Stearic Acid in a product composition right on the store page
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
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Sucrose, Sucrose Tristearate, Sunflower Seed Oil, Sunflower Seed Oil Glyceride, C10-18 Triglycerides, Fructooligosaccharides, Hydrolyzed Ulva Lactuca Extract, Passiflora Edulis Fruit Extract
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