What Is Peg-4 Polyglyceryl-2 Stearate?
Peg-4 Polyglyceryl-2 Stearate is an emulsifier made by joining stearic acid, a fatty acid commonly taken from coconut or palm oil, with small chains of glycerin and a few units of ethylene oxide. The result is a waxy, water-loving molecule that helps oil and water stay mixed. It first appeared in skin care during the late 1990s when formulators wanted plant-based alternatives to older petroleum-derived emulsifiers. Production starts with vegetable stearic acid, which is reacted with polyglycerin, then lightly “PEG-ylated” to improve water solubility. The finished ingredient is mild, biodegradable and easy to work with, so it shows up in creams, lotions, facial masks, makeup primers, sunscreens, baby products and rinse-off cleansers.
Peg-4 Polyglyceryl-2 Stearate’s Cosmetic Benefits/Uses
This ingredient is prized for one key job that quietly keeps many formulas looking and feeling their best.
Emulsifying: It binds oil and water into a stable blend, giving creams and lotions a smooth texture that spreads evenly without separating. A good emulsion also helps deliver active ingredients more uniformly across the skin, improves the feel of a product and extends shelf life by preventing clumps or watery layers.
Who Can Use Peg-4 Polyglyceryl-2 Stearate
This gentle emulsifier is generally well tolerated by all skin types, including dry, oily, combination and sensitive skin because it does not disrupt the skin barrier or leave a heavy film. Extremely reactive skin may still prefer simpler formulas, but Peg-4 Polyglyceryl-2 Stearate itself is unlikely to be the culprit if redness appears.
The ingredient is sourced from vegetable stearic acid and glycerin, so products made with it are usually suitable for vegans and vegetarians unless the rest of the formula contains animal derived additives.
The Cosmetic Ingredient Review panel lists it as safe for use during pregnancy and breastfeeding at typical concentrations. This is not medical advice and pregnant or nursing individuals should have a doctor review any products they plan to use.
Peg-4 Polyglyceryl-2 Stearate does not make skin more sensitive to sunlight and can be worn day or night without changing your sunscreen routine.
Potential Side Effects/Adverse Reactions
Reactions to topical Peg-4 Polyglyceryl-2 Stearate vary from person to person. The effects below are possible yet uncommon when the ingredient is used at the levels found in finished cosmetics.
- Mild skin irritation
- Allergic contact dermatitis in people already sensitive to polyethylene glycols or stearic acid derivatives
- Temporary stinging if a high concentration gets into the eyes
- Breakouts in very acne prone skin when the overall formula is rich in oils or waxes
- Trace 1,4-dioxane contamination if the raw material has not been properly purified, though this is tightly regulated in most countries
If you notice redness, itching or any other discomfort after using a product containing Peg-4 Polyglyceryl-2 Stearate stop using it and consult a healthcare professional if symptoms persist.
Comedogenic Rating
Rating: 1/5
Peg-4 Polyglyceryl-2 Stearate is mostly water soluble and used at low levels so it does not sit in pores like heavier oils. The stearic acid part is balanced by the PEG and polyglycerin chains which boost rinsability and reduce the chance of clogging. A rating of 1 reflects a very low but not zero risk because extremely acne prone skin can sometimes react to any fatty derivative.
Most people who are prone to breakouts can use products containing this emulsifier without an increase in pimples.
Its effect on pore clogging depends more on the overall formula. Rich occlusive creams built around this emulsifier may still feel heavy even though the emulsifier itself is light.
Summary
Peg-4 Polyglyceryl-2 Stearate is a plant sourced emulsifier that keeps oil and water blended so creams stay smooth and stable. It does this by anchoring its fatty stearate tail in oils while its PEG and glycerin sections bond with water, creating a fine mix that spreads evenly on skin.
The ingredient enjoys steady but not superstar popularity. It appears in many mid tier moisturizers, sunscreens and cleansers because it is easy to formulate with, vegan friendly and biodegradable yet it does not get the spotlight like trendy actives.
Regulatory panels consider it safe at typical cosmetic levels and reports of irritation are rare. As with any new product it is wise to patch test first to make sure your own skin agrees with the full formula.