What Is Peg-5 Stearate?
Peg-5 Stearate is a synthetic ingredient created by attaching roughly five units of ethylene oxide to stearic acid, a fatty acid that naturally occurs in vegetable oils and animal fats. The result is a waxy, water-soluble compound that bridges oil and water in a formulation. Chemists began experimenting with polyethylene glycol (PEG) derivatives in the 1950s to improve the texture and rinsability of personal care products, and Peg-5 Stearate quickly found favor for its gentle cleansing action and reliable emulsifying power.
Manufacturing starts with purifying stearic acid, usually sourced from coconut, palm or tallow. Through a controlled ethoxylation process, the acid is reacted with ethylene oxide until an average chain length of five oxyethylene units is reached. The final step neutralizes any residual reactants and filters out impurities, leaving a stable ingredient that meets cosmetic-grade standards.
You will most often see Peg-5 Stearate in facial cleansers, makeup removers, moisturizers, sunscreens, lightweight lotions, sheet masks and some rinse-off hair conditioners. Its ability to lift dirt while keeping formulas smooth makes it versatile for both wash-off and leave-on products marketed for normal, oily and combination skin.
Peg-5 Stearate’s Cosmetic Benefits/Uses
Formulators choose Peg-5 Stearate because it performs key jobs that improve how a product works and feels on the skin.
- Cleansing: Acts as a mild surfactant that loosens sweat, oil and makeup so they rinse away more easily, helping skin feel fresh without a tight or stripped sensation
- Emulsifying: Keeps water and oils blended into a uniform cream or lotion, preventing separation during storage and ensuring that active ingredients spread evenly when applied
Who Can Use Peg-5 Stearate
Most skin types, including oily, combination and normal, tolerate Peg-5 Stearate well because it provides gentle cleansing without leaving residue. Dry or highly sensitive skin usually does fine with it too, though people with a damaged skin barrier might prefer richer formulas that contain additional emollients.
The stearic acid used to make Peg-5 Stearate can come from either plant sources such as coconut or palm oil or from animal tallow. If you follow a vegan or vegetarian lifestyle check the product label or reach out to the manufacturer to confirm plant sourcing.
Available safety data indicate Peg-5 Stearate is considered low risk for pregnant or breastfeeding women when used topically. This is not medical advice so anyone who is expecting or nursing should clear any skincare product with a healthcare professional first.
The ingredient does not increase photosensitivity so it will not make skin more prone to sunburn. It is also fragrance free and nonreactive with most other common cosmetic ingredients, making it easy to layer with the rest of a routine.
Potential Side Effects/Adverse Reactions
Reactions to topical Peg-5 Stearate vary from person to person. The effects listed below are only potential issues and are unlikely for the average user when the ingredient is formulated correctly.
- Mild skin irritation such as redness or stinging, particularly on very sensitive or compromised skin
- Rare cases of allergic contact dermatitis in individuals with a specific sensitivity to polyethylene glycol derivatives
- Transient eye irritation if a cleanser containing Peg-5 Stearate accidentally gets into the eyes
- Temporary dryness or tightness when used in high concentrations or in formulas lacking additional moisturizers
- Trace contamination with 1,4-dioxane if manufacturing purification steps are not followed, though reputable brands test to keep levels within safety limits
If any discomfort, rash or other negative reaction occurs stop using the product and consult a qualified healthcare provider.
Comedogenic Rating
Rating: 1 out of 5
Peg-5 Stearate is highly water soluble and does not form the heavy oily film that typically clogs pores. Its molecular structure keeps it lightweight so it rinses cleanly and leaves minimal residue. For that reason it earns a low comedogenic score of 1.
This makes the ingredient generally suitable for people who are prone to acne or breakouts.
As with any PEG-based material, the final formula matters; a product packed with thick oils or waxes may still trigger congestion even if Peg-5 Stearate itself is low risk.
Summary
Peg-5 Stearate acts mainly as a mild cleanser and a dependable emulsifier. Its PEG portion likes water while the stearic acid tail likes oil, letting it lift dirt and makeup during rinsing and hold watery and oily ingredients together in a smooth stable blend.
You will see it in everyday cleansers, light lotions, sunscreens and sheet masks though it is not the most talked-about ingredient in beauty circles. Formulators appreciate its reliability and gentle feel so it quietly appears in many mass-market and mid-range products.
Current research and decades of use show it to be safe for topical application with only rare irritation issues. Still, individual skin can react differently so it is smart to do a quick patch test when trying any new product that contains Peg-5 Stearate.