What Is Peg-2 Stearate Se?
Peg-2 Stearate Se is a synthetic ingredient created by reacting stearic acid, a fatty acid often sourced from vegetable oils like coconut or palm, with an average of two units of ethylene oxide. The resulting material is then partially neutralised to improve stability and skin compatibility. This process, known as ethoxylation, turns the naturally water-resistant stearic acid into a substance that mixes well with both water and oil.
The path to cosmetic use began in the mid-20th century when formulators searched for safer, more efficient ways to blend oil and water in creams and lotions. Fatty acid ethoxylates like Peg-2 Stearate Se proved reliable, easy to produce at scale and mild on skin, leading to their rapid adoption in personal care products.
Manufacturing starts with purified stearic acid that is reacted in a controlled environment with ethylene oxide gas. After two average ethylene oxide units attach to each stearic acid molecule, the mixture is neutralised with a small amount of base. The final product is filtered, cooled and milled into flakes or pellets ready for formulation.
You will commonly find Peg-2 Stearate Se in moisturisers, facial cleansers, body lotions, sunscreens, liquid foundations and rinse-off masks where a smooth, uniform texture is important.
Peg-2 Stearate Se’s Cosmetic Benefits/Uses
In skincare and makeup formulas Peg-2 Stearate Se serves a single yet essential purpose.
As an emulsifying agent it helps oil and water stay blended, giving products a stable, creamy feel and preventing separation during storage and use. This stability improves spreadability on the skin and keeps active ingredients evenly distributed for consistent performance with every application.
Who Can Use Peg-2 Stearate Se
Peg-2 Stearate Se is generally well tolerated by most skin types including normal, oily, dry and combination skin. Because it has a light texture and sits on the surface rather than penetrating deeply it rarely feels heavy or greasy which makes it comfortable for acne-prone complexions too. Those with very reactive or highly sensitive skin should still pay attention to how their skin responds since any emulsifier has the potential to trigger irritation when the skin barrier is already compromised.
The ingredient itself can be sourced from either plant or animal stearic acid. Brands that wish to keep a formula vegan normally specify the use of vegetable-derived stearic acid so vegans and vegetarians should look for that clarification or ask the manufacturer if the supply chain is not stated.
Current safety data show no special restrictions for pregnant or breastfeeding women. That said this information is educational only and not medical advice so anyone who is expecting or nursing should have their healthcare provider review all personal care products before use.
Peg-2 Stearate Se does not increase the skin’s sensitivity to sunlight and there are no known interactions with common actives such as retinoids or vitamin C. It is also odorless and unlikely to interfere with fragrance-free routines.
Potential Side Effects/Adverse Reactions
Side effects from topical use of Peg-2 Stearate Se vary from person to person. The following list covers potential reactions but most consumers will not experience them when the ingredient is used at typical cosmetic levels.
- Mild redness or stinging, especially on compromised skin
- Temporary itching or dryness
- Contact dermatitis in individuals allergic to polyethylene glycol compounds
- In rare cases clogged pores that may lead to breakouts
If any undesirable reaction occurs stop using the product and consult a qualified healthcare professional or dermatologist.
Comedogenic Rating
On the standard 0–5 scale Peg-2 Stearate Se sits at about 1. Its molecular structure is largely water dispersible thanks to ethoxylation, so it does not readily build up inside pores. The stearic acid portion is diluted by the presence of just two ethylene oxide units, resulting in a light surface film rather than a heavy occlusive layer. Because of this low tendency to trap oil and debris it is generally considered safe for acne-prone or breakout-prone skin.
Formulas using high levels of additional rich oils or waxes can still feel heavy, which means the finished product—not the emulsifier alone—could contribute to congestion. Always look at the full ingredient list if clogged pores are a concern.
Summary
Peg-2 Stearate Se is an emulsifier that keeps water and oil blended so lotions, creams and sunscreens stay smooth and uniform. By lowering surface tension it creates a stable emulsion that spreads easily and delivers active ingredients evenly across the skin. Its reliability and mild sensory feel have made it a staple in mainstream skincare even though newer naturally derived emulsifiers have gained attention in recent years.
Current research and industry safety assessments show Peg-2 Stearate Se is low risk for irritation or pore clogging when used at normal cosmetic levels. As with any new product a simple patch test on a small area of skin first is a smart precaution to confirm personal compatibility.