Ingredient review
PEG-36 Stearate
INCI: PEG-36 Stearate
A reliable emulsifier that keeps creams and lotions stable, but may not be ideal for very sensitive or compromised skin.
In plain English
PEG-36 Stearate is a synthetic ingredient made from stearic acid (a fatty acid from plant or animal sources) and ethylene oxide. Its main job is to help water and oil blend together so your moisturizer or cleanser stays smooth and doesn't separate. Think of it as a tiny bridge that holds the two ingredients together. It's widely used because it's gentle and effective, but because it's made with ethylene oxide, some people prefer to avoid PEG compounds for personal or environmental reasons.
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-36 Stearate 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-36 Stearate.
- 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-36 Stearate is a polyethylene glycol (PEG) derivative of stearic acid. The '36' refers to the average number of ethylene oxide units in the molecule, which determines its water-loving properties. It is a white to off-white waxy solid at room temperature.
How it works
In a cosmetic formula, PEG-36 Stearate sits at the boundary between oil and water droplets. Its water-loving (hydrophilic) end dissolves in water, while its oil-loving (lipophilic) end dissolves in oil. This reduces surface tension and allows the two phases to form a stable, uniform emulsion that doesn't separate over time.
Pros
Effective emulsifier
PEG-36 Stearate reliably prevents oil and water from separating, giving your creams and lotions a consistent, pleasant texture that lasts on the shelf.
Low irritation risk
It is generally well-tolerated by most skin types, including sensitive skin, when used at typical concentrations in well-formulated products.
Cons and cautions
Potential trace impurities
The manufacturing process can leave behind trace amounts of 1,4-dioxane, a possible carcinogen. Reputable brands purify their ingredients to keep levels well below safety limits, but it's a concern for some consumers.
Not biodegradable
PEG compounds can persist in the environment, especially in water systems. This makes them less eco-friendly compared to some plant-based emulsifiers.
Best for
- People with normal to combination skin
- Anyone using standard moisturizers or cleansers who wants a stable, non-irritating formula
Use caution if
- Those with known sensitivity to PEG compounds
- Individuals seeking exclusively natural or biodegradable ingredients
Usage tips
Safety summary
PEG-36 Stearate is considered safe for use in cosmetics at typical concentrations. The main safety concern is potential contamination with 1,4-dioxane during manufacturing, but reputable suppliers purify the ingredient to meet safety standards. It has low irritation and comedogenic potential.
Research notes
The Cosmetic Ingredient Review (CIR) panel reviewed PEG stearates and concluded they are safe as used in cosmetics. Studies show low acute toxicity and minimal skin irritation. No significant evidence links properly purified PEG-36 Stearate to adverse health effects.
Common label clues
- Typical concentration
- 1–5% in most leave-on and rinse-off products
- Regulatory status
- Approved for use in cosmetics by the FDA (as an indirect food additive) and by the European Commission under the CosIng database. The Cosmetic Ingredient Review (CIR) panel has deemed PEG stearates safe as used in cosmetics.
- Common uses
- Moisturizers, Cleansers, Makeup removers, Sunscreens
- Environmental note
- PEG compounds are not readily biodegradable and may accumulate in aquatic environments. Some manufacturers are moving toward bio-based or biodegradable alternatives.
Good to know
- The 'PEG' number (36) indicates the average polymer length; higher numbers mean more water solubility.
- PEG-36 Stearate is often used in combination with other emulsifiers to fine-tune product feel.
- It is considered safe by major regulatory bodies when used as directed.
Common questions
What is PEG-36 Stearate in beauty products?
PEG-36 Stearate is a synthetic ingredient made from stearic acid (a fatty acid from plant or animal sources) and ethylene oxide. Its main job is to help water and oil blend together so your moisturizer or cleanser stays smooth and doesn't separate. Think of it as a tiny bridge that holds the two ingredients together. It's widely used because it's gentle and effective, but because it's made with ethylene oxide, some people prefer to avoid PEG compounds for personal or environmental reasons.
What does PEG-36 Stearate do in a beauty product?
In a cosmetic formula, PEG-36 Stearate sits at the boundary between oil and water droplets. Its water-loving (hydrophilic) end dissolves in water, while its oil-loving (lipophilic) end dissolves in oil. This reduces surface tension and allows the two phases to form a stable, uniform emulsion that doesn't separate over time.
Is PEG-36 Stearate safe for most people?
PEG-36 Stearate is considered safe for use in cosmetics at typical concentrations. The main safety concern is potential contamination with 1,4-dioxane during manufacturing, but reputable suppliers purify the ingredient to meet safety standards. It has low irritation and comedogenic potential.
Who should be careful with PEG-36 Stearate?
Those with known sensitivity to PEG compounds Individuals seeking exclusively natural or biodegradable ingredients
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.