What Is Peg-90?
Peg-90 is a synthetic ingredient made by joining together many units of ethylene oxide, forming a chain of about 90 repeating parts. The scientific name Poly(oxy-1,2-ethanediyl), .alpha.-hydro-.omega.-hydroxy- points to this long chain ending in two hydroxyl groups that help it mix well with water. Chemically speaking it belongs to the large family of polyethylene glycols that have been used in personal care since the 1940s when manufacturers first looked for reliable water-soluble helpers in creams and cleansers.
The manufacturing process is straightforward: ethylene oxide gas is added step by step to a starter molecule of ethylene glycol under heat and pressure. By controlling the number of additions producers stop the reaction at an average of 90 units, giving Peg-90 its name. Because the raw materials are petroleum-derived or can come from fermented plant feedstocks, Peg-90 itself is considered synthetic though parts of its supply chain may be plant sourced.
Peg-90 shows up in many leave-on and rinse-off products. You are likely to find it in facial masks, daily moisturizers, lightweight serums, anti-aging lotions, makeup removers, shower gels, shampoos and styling creams. Formulators prize it for its ability to pull in moisture and to keep other ingredients evenly mixed so the product stays smooth from the first use to the last.
Peg-90’s Cosmetic Benefits/Uses
Peg-90 plays two key roles that improve both the feel and performance of a formula.
- Humectant – draws water from the environment and from deeper skin layers up to the surface, helping skin stay soft, plump and comfortable throughout the day
- Solvent – dissolves hard-to-mix ingredients such as certain fragrances, plant extracts and active agents so the final product is clear, stable and easy to spread
Who Can Use Peg-90
Peg-90 is generally well tolerated by most skin types including dry, normal and combination skin because of its water-binding ability and lightweight texture. Oily and acne-prone skin can usually use it without issues since it is non-greasy and rinses clean, though very sensitive or compromised skin may prefer simpler formulas with fewer synthetic additives.
The ingredient is synthesized from petroleum or plant-derived feedstocks and contains no animal by-products, making it suitable for vegetarians and vegans. That said individual finished products may include other animal-derived ingredients so checking the full label is still important.
Current research shows no specific risks linked to topical Peg-90 during pregnancy or breastfeeding. This information is not medical advice and pregnant or nursing individuals should review any skincare product with their healthcare provider to be safe.
Peg-90 does not cause photosensitivity, so it will not make skin more prone to sunburn. It also does not interfere with common actives like retinoids or vitamin C, allowing it to fit easily into most routines.
Potential Side Effects/Adverse Reactions
Side effects from topical Peg-90 can vary between individuals. The points below outline potential reactions but most users should not expect these outcomes when the ingredient is used correctly in a well-formulated product.
- Mild skin irritation such as redness stinging or itching
- Contact dermatitis in people with a known polyethylene glycol allergy
- Eye irritation if a product containing high levels of Peg-90 accidentally gets into the eyes
- Increased penetration of other ingredients which can occasionally heighten sensitivity to those ingredients
If any discomfort or adverse reaction develops discontinue use and consult a healthcare professional.
Comedogenic Rating
Rating: 0/5
Peg-90 is a large water-soluble molecule that does not sit heavily on skin or form an occlusive film, so it is unlikely to clog pores. Because it readily dissolves in water and rinses away cleanly even in leave-on formulas it poses minimal risk of trapping oil or debris in follicles. For these reasons Peg-90 is generally considered suitable for acne-prone or breakout-prone skin. Formulators sometimes pick it precisely because it can thin out richer emulsions and make them feel lighter, which further reduces the chance of pore blockage.
Summary
Peg-90 functions first as a humectant, pulling moisture from the air and deeper skin layers toward the surface to keep skin soft and supple. Its second key role is as a solvent that helps dissolve fragrances, botanical extracts and active ingredients so a formula stays clear stable and easy to spread. These two jobs hinge on its long chain of ethylene oxide units that love water and mix seamlessly with both watery and some oily components.
The ingredient is not a headline star like hyaluronic acid or niacinamide, yet it shows up quietly in many everyday cleansers, moisturizers and hair products because it is dependable affordable and easy to formulate with.
Overall safety is high with only rare reports of irritation or allergy. As with any new product it is smart to perform a quick patch test when Peg-90 appears on the label just to be thorough.