What Is Peg-90 Diisostearate?
Peg-90 Diisostearate is a synthetic ingredient made by attaching about 90 units of ethylene oxide to diisostearic acid, a fatty acid that usually comes from vegetable oils such as soybean or rapeseed. The result is a waxy, water-soluble compound that works well at the skin’s surface. Chemists began adding this type of ingredient to cosmetics in the late 1970s when the industry wanted gentler alternatives to strong soaps. Today it is produced in large reactors where diisostearic acid is first purified then reacted with ethylene oxide under heat and pressure. The finished material is blended into liquid form for easy use in factories.
Because of its mild nature and ability to mix oil with water, Peg-90 Diisostearate shows up in a wide range of rinse-off products. You will find it in facial cleansers, body washes, micellar waters, baby shampoos, cleansing balms and some cream masks that need a light foaming boost. Brands also add it to exfoliating scrubs to help the grains rinse away cleanly.
Peg-90 Diisostearate’s Cosmetic Benefits/Uses
This ingredient is valued mainly for one job in a formula.
Cleansing: Peg-90 Diisostearate is a non-ionic surfactant that lowers the surface tension between oil and water so dirt, sweat and makeup can lift off the skin and rinse away. It creates a soft creamy lather, leaves little residue and helps other ingredients spread evenly, which means products feel gentle yet effective during use.
Who Can Use Peg-90 Diisostearate
Because it is a mild non-ionic surfactant, Peg-90 Diisostearate is generally well tolerated by normal, oily, dry and sensitive skin types. Its creamy lather cleans without stripping natural oils so even reactive or mature skin usually fares well. There are no specific skin conditions that automatically rule it out, though people with a known allergy to polyethylene glycols should avoid it.
The diisostearic acid used to make this ingredient is typically sourced from plant oils and no animal-derived substances are involved in production, making it acceptable for vegan and vegetarian lifestyles. Always check the finished product label in case other ingredients are not plant based.
Current safety data indicate that Peg-based surfactants are not linked to developmental concerns, so products containing Peg-90 Diisostearate are generally considered safe for those who are pregnant or breastfeeding. This is not medical advice and anyone who is expecting or nursing should discuss all skincare products with a qualified healthcare provider to be on the safe side.
Peg-90 Diisostearate does not make skin more sensitive to sunlight and it has no known effect on tanning products or sunscreen performance. It is also compatible with leave-on or rinse-off formulations used around the eyes.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-90 Diisostearate vary from person to person. The points below outline potential side effects that could occur, but they are uncommon when the ingredient is used at the levels typically found in cosmetic formulas.
- Mild skin irritation such as redness or stinging, usually in very sensitive individuals
- Dryness or tightness if used in a high foaming wash without adequate moisturizers
- Allergic contact dermatitis in people with a specific PEG allergy
- Temporary eye irritation if the product is accidentally rubbed into the eyes before rinsing
If you notice any of these reactions stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 1 out of 5
Peg-90 Diisostearate is highly water-soluble and used at low levels in rinse-off cleansers, so it spends very little time sitting on the skin. The bulky PEG portion keeps the fatty acid part from clumping together in pores, which is why the chance of clogging is considered very low.
For most people with acne-prone or breakout-prone skin this ingredient is unlikely to trigger new blemishes.
Keep in mind that a finished product’s overall formula, especially any heavy oils or waxes it contains, can raise the comedogenic potential even if Peg-90 Diisostearate itself is low.
Summary
Peg-90 Diisostearate is a gentle non-ionic surfactant that helps water mix with oil so dirt, makeup and excess sebum rinse away easily. It creates a creamy lather, leaves minimal residue and supports an even spread of other ingredients across the skin.
While not a headline buzzword it is a steady worker that shows up in many everyday cleansers, body washes and baby shampoos where mildness is a selling point.
Safety reviews show it to be low risk for irritation or toxicity when used as directed. Still, everyone’s skin is different so it is wise to patch test any new product containing Peg-90 Diisostearate before making it part of a regular routine.