What Is Peg-6 Diisostearate?
Peg-6 Diisostearate is a synthetic ingredient created by reacting isostearic acid, a fatty acid usually obtained from vegetable oils like coconut or soybean, with polyethylene glycol. The “6” in its name tells us the average number of ethylene oxide units added during manufacturing, which affects how well it mixes oil and water. First introduced to personal care labs in the late 1970s, it offered formulators a reliable way to keep creams and lotions from separating, replacing some older waxy emulsifiers that felt heavy on skin.
The production process starts with purified isostearic acid that is esterified with polyethylene glycol under controlled heat and pressure. The resulting liquid is then filtered and standardized so each batch meets cosmetic grade safety and purity standards.
Because Peg-6 Diisostearate is good at bridging oil and water, you will find it in face creams, lightweight lotions, cleansing balms, makeup removers, sunscreens, tinted moisturizers and hair conditioners. It is valued for giving products a smooth, non-greasy feel and helping active ingredients distribute evenly across skin or hair.
Peg-6 Diisostearate’s Cosmetic Benefits/Uses
Peg-6 Diisostearate’s main role in beauty products is as an emulsifier. By lowering the surface tension between oil and water, it keeps formulas stable so they look and feel the same from the first use to the last. A well-built emulsion spreads more easily, absorbs better and delivers consistent performance, which is why many brands rely on this ingredient in both skincare and hair care.
Who Can Use Peg-6 Diisostearate
Peg-6 Diisostearate is considered friendly to most skin types including oily, combination, normal and dry skin because it is lightweight and leaves little residue. Sensitive skin usually tolerates it well, though anyone with a known sensitivity to polyethylene glycols or fatty acid esters might choose to steer clear.
The ingredient is synthetically produced from plant-derived isostearic acid and petroleum-based ethylene oxide, so finished material is free of animal by-products. That makes it suitable for both vegans and vegetarians.
Current data do not flag Peg-6 Diisostearate as an ingredient of concern for women who are pregnant or breastfeeding. Still, this is not medical advice and anyone expecting or nursing should discuss any skincare product with a healthcare professional to be extra safe.
Peg-6 Diisostearate does not increase photosensitivity, so it will not make skin more prone to sunburn. It is also odorless and nonvolatile, so it will not interfere with fragrance or essential oils chosen for a formula.
Potential Side Effects/Adverse Reactions
Side effects from topical use of Peg-6 Diisostearate differ from person to person. The following points list potential but uncommon reactions. When the ingredient is used at typical cosmetic levels most people will not notice any of these issues.
- Mild skin irritation especially on compromised or highly sensitive skin
- Contact dermatitis in individuals allergic to polyethylene glycols
- Eye stinging if a product containing it gets into the eyes during use
- Follicular acne-like bumps in rare cases of very acne-prone skin
If you notice redness, itching or any persistent discomfort stop using the product and consult a healthcare provider or dermatologist.
Comedogenic Rating
Rating: 1 out of 5. Peg-6 Diisostearate is a PEGylated fatty acid ester that is highly water dispersible, so it rinses off more easily than heavier oils or waxes that can clog pores. Its lightweight texture means it tends to sit on the surface without forming the kind of occlusive film that traps debris inside follicles. For most people including those prone to blemishes it is unlikely to provoke breakouts, though exceptionally acne-sensitive users should still watch how their skin responds.
Because it also acts as a mild surfactant in cleansing formulas, it can actually help lift excess sebum when used in wash-off products. Leave-on creams that contain high levels of this ingredient are uncommon, which further lowers the real-world risk of pore congestion.
Summary
Peg-6 Diisostearate is a versatile emulsifier that keeps oil and water perfectly blended, giving lotions and cleansers a smooth stable texture while helping active ingredients spread evenly. It does this by lowering surface tension so droplets of oil disperse throughout water or vice versa, preventing separation during storage and use.
The ingredient is moderately popular: not as widely known as classic emulsifiers like glyceryl stearate yet valued by formulators who want a lighter feel and reliable performance. You will mainly spot it in cleansers, makeup removers, lightweight creams and sunscreens where a clean rinse or quick absorption is desired.
Current safety data show a low risk of irritation or sensitization for most skin types and its comedogenic rating is low, making it generally safe to use. As with any new skincare ingredient it is wise to perform a quick patch test when trying a product for the first time so you can confirm your skin’s personal tolerance.