What Is Peg-90 Stearate?
Peg-90 Stearate is a synthetic ingredient made by attaching about 90 units of ethylene oxide to stearic acid, a fatty acid most often sourced from plant oils like coconut or palm. The result is a waxy, water-soluble compound that can link oil and water together. Chemists began experimenting with this type of molecule in the mid-20th century when the demand for gentler, more effective cleansers grew. By tweaking the length of the ethylene oxide chain they discovered versions, such as Peg-90 Stearate, that cleaned well without stripping skin.
Manufacturing starts with purified stearic acid. Through a process called ethoxylation, ethylene oxide gas is added under controlled heat and pressure. The number 90 in the name tells us the average number of ethylene oxide units that become attached. After neutralization and purification the ingredient is ready for cosmetic use.
You will mainly find Peg-90 Stearate in facial cleansers, body washes, exfoliating scrubs, makeup removers and some shampoo formulas. It may also appear in masks or micellar waters that aim to lift away dirt and excess oil while keeping the formula mild.
Peg-90 Stearate’s Cosmetic Benefits/Uses
In skin and hair care products Peg-90 Stearate serves one key purpose that brings several practical advantages.
Cleansing: The molecule has a water-loving end and an oil-loving end, so it can surround oily grime and suspend it in water for easy rinsing. This action helps formulas remove makeup, sunscreen, sweat and pollution while feeling gentle and non-greasy. Because it is milder than many traditional surfactants it is often chosen for sensitive skin cleansers that still need good foaming and rinsing performance.
Who Can Use Peg-90 Stearate
Peg-90 Stearate is generally suitable for most skin types including normal, oily, combination, dry and sensitive skin because it cleanses without the harsh stripping effect linked to stronger surfactants. Those with very dry or compromised skin barriers should still pair it with a moisturizing routine since any surfactant can remove some surface lipids.
The ingredient itself is synthesized from stearic acid that is usually sourced from plant oils, so formulations that specify a vegetable origin can be considered vegan and vegetarian friendly. If the label does not clarify the source consumers who avoid animal-derived ingredients may wish to confirm this information with the brand.
Current safety data indicate no special concerns for pregnant or breastfeeding people when Peg-90 Stearate is used in rinse-off or leave-on cosmetics. Absorption through intact skin is minimal. This is not medical advice and anyone who is pregnant or nursing should review all personal care products with a qualified healthcare professional before use.
Peg-90 Stearate does not cause photosensitivity so it will not make skin more prone to sunburn. It is also mild enough for use in products aimed at children or those with reactive skin when formulated correctly.
Potential Side Effects/Adverse Reactions
Reactions to topical Peg-90 Stearate differ from person to person. The following list covers potential side effects yet they are uncommon when the ingredient is used at typical cosmetic levels and produced to industry standards.
Skin irritation such as redness stinging or itching
Dryness or a feeling of tightness especially on very dry or compromised skin
Allergic contact dermatitis in individuals sensitive to polyethylene glycol compounds
Eye irritation if the product accidentally enters the eyes
If any discomfort or adverse reaction occurs stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Peg-90 Stearate is highly water soluble and designed to rinse away cleanly so it does not linger in pores or form a heavy film. Its large hydrophilic structure reduces its ability to mix with skin sebum which is why it earns a low score of 1. This makes it generally suitable for people who are prone to acne or breakouts.
No data suggest that this ingredient promotes fungal acne and it is often paired with non-occlusive co-surfactants that further lower clogging potential. Formulas with high levels of heavy oils or waxes could still cause congestion regardless of Peg-90 Stearate so the overall product composition matters.
Summary
Peg-90 Stearate’s main role is cleansing. The molecule has a water-loving polyethylene glycol chain and an oil-loving stearic acid tail which work together to lift dirt makeup and excess oil then allow them to rinse away. This dual nature lets formulators create gentle foaming washes that clean effectively while feeling mild on skin and hair.
Although not the flashiest ingredient it appears in a fair number of modern cleansers micellar waters and body washes thanks to its balance of gentleness and performance. It tends to fly under the radar because it is usually part of a wider surfactant blend rather than the star of the show yet chemists value it for boosting mildness.
Current safety assessments rate Peg-90 Stearate as low risk for irritation or systemic toxicity when used at cosmetic concentrations. Still every skin is different so it is always wise to patch test any new product that contains this or any other surfactant before adding it to your routine.