What Is Peg-40 Sorbitan Perisostearate?
Peg-40 Sorbitan Perisostearate is a liquid or soft wax derived from sorbitol, a sugar alcohol that comes from corn or other plant sources. Chemists first reacted sorbitol with fatty acids from isostearic acid to create sorbitan isostearate, then added about forty units of ethylene oxide to give it water-loving properties. This balance of oil-friendly and water-friendly parts makes it an effective helper in modern skincare.
The ingredient gained attention in the 1970s when formulators were looking for milder alternatives to harsh soaps. Its ability to blend oil and water without irritation quickly made it a staple in cleansers and creams. Today manufacturers produce it in closed reactors where precise temperature and pressure control allow ethoxylation to occur safely, after which the material is purified and quality tested before use.
You will most often find Peg-40 Sorbitan Perisostearate in facial cleansers, micellar waters, makeup removers, hydrating masks, lightweight moisturizers, sprayable lotions and some anti-aging serums that need a smooth, stable texture.
Peg-40 Sorbitan Perisostearate’s Cosmetic Benefits/Uses
In a formula this ingredient pulls double duty, improving both performance and feel.
- Cleansing: Its surfactant nature loosens dirt, excess oil and makeup so they rinse away with water, leaving skin fresh without a tight after-feel
- Emulsifying: It keeps water and oil phases mixed, preventing separation in creams or lotions. This gives products a consistent texture, longer shelf life and a pleasant spread on the skin
Who Can Use Peg-40 Sorbitan Perisostearate
This multitasking ingredient is generally well tolerated by all skin types including dry, normal, combination, oily and even sensitive skin because it is mild and non-stripping. Very acne-prone users who react to any fatty esters may want to watch how their skin responds, though its comedogenic tendency is considered low.
Peg-40 Sorbitan Perisostearate is suitable for vegans and vegetarians because the sorbitol base comes from plant starch and the fatty acids are sourced from vegetable oils rather than animal fats. The polyethylene glycol portion is synthetic and also contains no animal derivatives.
No data suggest problems for women who are pregnant or breastfeeding when this ingredient is used topically in rinse-off or leave-on products. This is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of any product to a qualified healthcare provider before use to be safe.
The molecule does not absorb UV light so it does not make skin more sensitive to the sun. It is also fragrance-free and dye-free by nature, which reduces the likelihood of scent-related reactions.
Potential Side Effects/Adverse Reactions
Reactions to topical Peg-40 Sorbitan Perisostearate differ from person to person. The following points outline potential issues, though most users will not experience them when the ingredient is used at normal cosmetic levels.
- Mild stinging or redness on very sensitive skin, especially if the barrier is already compromised
- Temporary dryness if used in a high-foaming cleanser without added moisturizers
- Rare allergic contact dermatitis leading to itching or small bumps
- Eye irritation if the product accidentally gets into the eyes before rinsing
If any of these effects occur stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1/5
Peg-40 Sorbitan Perisostearate has a low tendency to clog pores because its PEG groups make it highly water compatible, allowing it to rinse away instead of sitting in pores. The isostearic acid portion is a branched fatty acid that is less likely to pack tightly on the skin than straight-chain oils, further reducing the risk of comedones.
With this low score it is generally suitable for acne-prone or breakout-prone skin, especially in rinse-off cleansers or light emulsions. Extremely reactive individuals may still prefer to monitor their skin when trying a new formula.
No studies show that it exacerbates fungal acne, and it is free of heavy silicones or waxes that often raise the clogging potential.
Summary
Peg-40 Sorbitan Perisostearate works as a gentle cleanser and reliable emulsifier. Its dual nature lets it grab onto oil-based grime while staying soluble in water so it lifts away makeup dirt and sunscreen without stripping. In creams and lotions it keeps the water and oil parts blended, giving products a smooth stable texture.
Although it is not as famous as ingredients like glycerin or hyaluronic acid, formulators reach for it often because it is dependable inexpensive and easy to incorporate into a wide range of textures from micellar waters to lightweight moisturizers.
Safety data and decades of use show it is low risk for irritation or pore clogging when used at normal cosmetic levels. As with any new skincare ingredient it is wise to perform a small patch test when first trying a product that contains it to make sure your individual skin agrees with the formula.