What Is Peg-400?
Peg-400 is a petroleum-derived liquid polymer made by linking together about 400 units of ethylene oxide, resulting in a clear odorless syrup that mixes easily with water and many oils. Chemists group it under the larger family of polyethylene glycols, materials first explored in the 1940s when manufacturers searched for versatile carriers for creams and lotions. Today most suppliers create Peg-400 through controlled addition of ethylene oxide to ethylene glycol, followed by careful purification to remove residual reactants. The finished ingredient is stable, has a neutral taste and smell, and is considered non-sticky, qualities that help it fit seamlessly into modern formulas. You will commonly spot it in lightweight serums, sheet masks, gel moisturizers, cleansing balms, hair conditioners and many targeted treatment products where even spreading and consistent texture are important.
Peg-400’s Cosmetic Benefits/Uses
Formulators choose Peg-400 for three key roles that improve how a product feels, looks and performs on the skin.
- Binding: Peg-400 helps keep solid particles or actives evenly dispersed so every pump or scoop delivers the same dose, preventing separation over time.
- Emulsion stabilising: It reinforces the bond between oil and water phases, guarding against splitting and extending shelf life which means the cream stays smooth from the first use to the last.
- Solvent: Peg-400 can dissolve a wide range of ingredients from plant extracts to certain vitamins, allowing brands to load higher levels of actives without cloudiness or grit while retaining a light feel on skin.
Who Can Use Peg-400
Peg-400 is generally well tolerated by all skin types including dry, oily, combination and even most sensitive complexions because it is lightweight, non greasy and has a low likelihood of clogging pores. Very reactive or compromised skin may still prefer to introduce it slowly since any synthetic polymer has a slim chance of causing irritation in those with a damaged barrier.
The ingredient is produced from petroleum based feedstocks, not animal sources, so it is suitable for both vegans and vegetarians. As always, consumers who avoid animal testing will still want to confirm the final product’s cruelty free status with the brand.
Peg-400 is viewed as low risk for women who are pregnant or breastfeeding when used in topical cosmetics. This is not medical advice and anyone expecting or nursing should show any product they plan to use to their healthcare provider to be certain it fits their personal situation.
The polymer does not cause photosensitivity and has no known interactions with sunlight, so daytime use does not require extra protective measures beyond a regular sunscreen routine. There are also no reported incompatibilities with common active ingredients, making it easy to layer with other products.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-400 can differ between individuals. The points below cover potential side effects yet most people will not encounter them when the ingredient is properly formulated and used.
- Mild skin irritation such as redness or itching
- Contact dermatitis in those specifically allergic to polyethylene glycols
- Temporary stinging if the product gets into the eyes
- Enhanced penetration of other actives that could heighten their own irritation potential
If any of these issues develop stop using the product and consult a healthcare professional or dermatologist.
Comedogenic Rating
Comedogenic rating: 0/5
Peg-400 is a small water-soluble molecule that does not sit on the skin’s surface or trap oil in pores, so it earns the lowest possible score. It is used mainly to keep formulas uniform and to dissolve actives rather than to create an occlusive layer. Because it rinses away easily and leaves minimal residue most dermatology references list it as non-comedogenic.
That means Peg-400 is generally suitable for acne-prone or breakout-prone skin. Very oily skin types might still prefer lightweight leave-on products overall but Peg-400 itself is unlikely to trigger new blemishes.
No special storage or temperature concerns affect its pore-clogging potential and suppliers consistently remove heavy waxy impurities that could change its rating.
Summary
Peg-400 acts as a binder stabiliser and solvent. It keeps particles evenly suspended so every squeeze of a cream delivers the same dose helps oil and water stay blended for a smooth texture and dissolves a wide range of extracts and vitamins so formulas can carry more actives without feeling heavy.
Because of these talents it pops up in everything from clear serums to cleansing balms though it is not a headline ingredient consumers brag about on social media. Brands value it behind the scenes for reliability and ease of use.
Safety profiles from cosmetic regulatory bodies rate Peg-400 as low risk with irritation or allergy being uncommon. Still everyone’s skin is unique so try a small patch first when testing any new product containing Peg-400 to confirm personal compatibility.