Ingredient review
PEG-135
INCI: PEG-135
PEG-135 is a safe, widely used thickener and emulsifier, but its production may involve potentially concerning impurities that are tightly regulated.
In plain English
PEG-135 is a synthetic ingredient made from ethylene oxide. It helps thicken products and keeps oil and water mixed together so your lotion or cream stays smooth. It also makes your skin feel soft. The number 135 refers to the average molecular weight of the polymer chain. Higher numbers mean thicker consistency. PEG-135 is considered safe in cosmetics at typical levels, but some people prefer to avoid PEGs due to concerns about manufacturing impurities like 1,4-dioxane, which are strictly limited by regulators.
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-135 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-135.
- 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-135 is a polyethylene glycol (PEG) compound with an average molecular weight of about 135. It is a clear, viscous liquid that acts as a humectant, thickener, and emulsifier.
How it works
In a cosmetic formula, PEG-135 helps dissolve other ingredients, stabilizes emulsions (mixing water and oil), and increases the product's viscosity. It also forms a thin film on the skin that can help retain moisture.
Pros
Effective thickener
PEG-135 gives creams and lotions a smooth, luxurious feel without being greasy.
Low irritation risk
At typical concentrations, PEG-135 is very gentle and rarely causes skin reactions.
Cons and cautions
Synthetic origin
PEG-135 is petroleum-derived, which may not align with natural or eco-conscious preferences.
Manufacturing impurity concern
Trace amounts of 1,4-dioxane can form during production, though levels are strictly regulated to be safe.
Best for
- Anyone using conventional creams, lotions, or cleansers
- People with normal to dry skin looking for a gentle thickener
Use caution if
- Those seeking 100% natural or organic formulations
- Individuals with known sensitivity to PEG compounds (rare)
Usage tips
Safety summary
PEG-135 is considered safe for cosmetic use at typical concentrations. The main safety concern is potential contamination with 1,4-dioxane, a possible carcinogen, but regulatory limits keep levels well below harmful thresholds. Skin irritation is rare.
Research notes
The Cosmetic Ingredient Review (CIR) panel reviewed PEGs and concluded they are safe as used. Studies show low acute toxicity and minimal skin irritation. No significant evidence links PEG-135 to long-term health risks when used in cosmetics.
Common label clues
- Typical concentration
- 0.5% to 5% in leave-on products; up to 10% in rinse-off products
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission. The Cosmetic Ingredient Review (CIR) panel has deemed PEGs safe as used, with restrictions on 1,4-dioxane levels.
- Common uses
- Creams, Lotions, Cleansers, Hair products
- Environmental note
- PEGs are generally biodegradable, but their production from petroleum raises sustainability concerns. Some PEGs may persist in aquatic environments at low levels.
Good to know
- PEG-135 is often used in combination with other PEGs to fine-tune product texture.
- The number after PEG indicates the average molecular weight; lower numbers are more liquid, higher numbers are more solid.
Common questions
What is PEG-135 in beauty products?
PEG-135 is a synthetic ingredient made from ethylene oxide. It helps thicken products and keeps oil and water mixed together so your lotion or cream stays smooth. It also makes your skin feel soft. The number 135 refers to the average molecular weight of the polymer chain. Higher numbers mean thicker consistency. PEG-135 is considered safe in cosmetics at typical levels, but some people prefer to avoid PEGs due to concerns about manufacturing impurities like 1,4-dioxane, which are strictly limited by regulators.
What does PEG-135 do in a beauty product?
In a cosmetic formula, PEG-135 helps dissolve other ingredients, stabilizes emulsions (mixing water and oil), and increases the product's viscosity. It also forms a thin film on the skin that can help retain moisture.
Is PEG-135 safe for most people?
PEG-135 is considered safe for cosmetic use at typical concentrations. The main safety concern is potential contamination with 1,4-dioxane, a possible carcinogen, but regulatory limits keep levels well below harmful thresholds. Skin irritation is rare.
Who should be careful with PEG-135?
Those seeking 100% natural or organic formulations Individuals with known sensitivity to PEG compounds (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.