Ingredient review
PEG-450
INCI: PEG-450
PEG-450 is a safe, widely used synthetic thickener and humectant that helps stabilize formulas and improve texture, but it may be contaminated with impurities in poorly manufactured products.
In plain English
PEG-450 is a type of polyethylene glycol, a synthetic ingredient made from petroleum. In skincare, it acts like a sponge to hold water (humectant) and also helps thicken products so they feel smooth and spread easily. It's commonly found in creams, lotions, and cleansers. While generally safe, some people prefer to avoid PEGs due to concerns about potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, though reputable brands test for purity.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-450 is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging PEG-450.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
PEG-450 is a synthetic polymer belonging to the polyethylene glycol family, with an average molecular weight of around 450 g/mol. It is produced by polymerizing ethylene oxide and is a clear, viscous liquid at room temperature.
How it works
In a cosmetic product, PEG-450 acts as a humectant by attracting and retaining moisture from the air or deeper skin layers. It also functions as a thickener, increasing the viscosity of a formula to give it a richer, more luxurious feel. Additionally, it can help dissolve other ingredients and improve the spreadability of the product on the skin.
Pros
Effective humectant
PEG-450 helps draw moisture into the skin, keeping it hydrated and plump, especially in creams and lotions.
Improves formula feel
It thickens products without making them greasy, giving a smooth, spreadable texture that many users enjoy.
Cons and cautions
Potential impurities
If not properly purified, PEG-450 can contain trace amounts of ethylene oxide or 1,4-dioxane, which are potential carcinogens. Reputable brands test for these.
Synthetic origin
Derived from petroleum, it may not align with a natural or eco-conscious skincare philosophy.
Best for
- Anyone looking for a well-formulated, stable moisturizer or cleanser
- People with normal to dry skin who benefit from extra humectants
Use caution if
- Those who strictly avoid synthetic or petroleum-derived ingredients
- Individuals with known sensitivity to polyethylene glycols (rare)
Usage tips
Safety summary
PEG-450 is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, which is why choosing products from reputable, quality-tested brands is important. Skin irritation is rare.
Research notes
Studies show PEGs are well-tolerated on skin and have low acute toxicity. The Cosmetic Ingredient Review (CIR) panel has deemed PEGs safe as used in cosmetics, provided impurities are controlled. Research on 1,4-dioxane contamination has led to industry guidelines for purification.
Common label clues
- Typical concentration
- Typically 1–10% of the formula
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database, with no concentration restrictions. However, manufacturers are advised to limit 1,4-dioxane impurities to low levels.
- Common uses
- Creams, Lotions, Serums, Cleansers
- Environmental note
- PEGs are generally biodegradable, but their production from petroleum contributes to fossil fuel use. Some PEGs can be persistent in aquatic environments at high concentrations.
Good to know
- PEG-450 is water-soluble and rinses off easily, making it suitable for cleansers.
- The number '450' refers to the average molecular weight; lower numbers are more liquid, higher numbers are more solid.
Common questions
What is PEG-450 in beauty products?
PEG-450 is a type of polyethylene glycol, a synthetic ingredient made from petroleum. In skincare, it acts like a sponge to hold water (humectant) and also helps thicken products so they feel smooth and spread easily. It's commonly found in creams, lotions, and cleansers. While generally safe, some people prefer to avoid PEGs due to concerns about potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, though reputable brands test for purity.
What does PEG-450 do in a beauty product?
In a cosmetic product, PEG-450 acts as a humectant by attracting and retaining moisture from the air or deeper skin layers. It also functions as a thickener, increasing the viscosity of a formula to give it a richer, more luxurious feel. Additionally, it can help dissolve other ingredients and improve the spreadability of the product on the skin.
Is PEG-450 safe for most people?
PEG-450 is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, which is why choosing products from reputable, quality-tested brands is important. Skin irritation is rare.
Who should be careful with PEG-450?
Those who strictly avoid synthetic or petroleum-derived ingredients Individuals with known sensitivity to polyethylene glycols (rare)
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.