Ingredient review
PEG-90 Stearate
INCI: PEG-90 Stearate
A reliable synthetic emulsifier that helps create smooth, stable creams and lotions, but may be too heavy for very oily or acne-prone skin.
In plain English
PEG-90 Stearate is a man-made ingredient that helps oil and water mix together in your skincare products. Think of it as a bridge that keeps the formula from separating into layers. It also makes the product feel thicker and creamier. The 'PEG' part means it has been processed with ethylene oxide to make it water-friendly, and '90' refers to the length of the polymer chain, which affects how it behaves. It is generally considered safe and gentle, but because it is a thicker emulsifier, it might feel a bit heavy on very oily skin.
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-90 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-90 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-90 Stearate is a synthetic polymer made by reacting stearic acid (a fatty acid) with polyethylene glycol (PEG). It belongs to a family of emulsifiers that help stabilize water-and-oil mixtures.
How it works
It reduces the surface tension between oil and water, allowing them to blend into a uniform cream or lotion. Its long polymer chain also adds viscosity, giving products a rich, spreadable texture.
Pros
Stable emulsions
PEG-90 Stearate reliably prevents oil and water from separating, so your cream stays smooth and effective from first use to last.
Gentle on skin
It has a low irritation and comedogenic risk, making it suitable for most skin types, including sensitive skin.
Cons and cautions
Can feel heavy
Because it thickens formulas, products with PEG-90 Stearate may feel richer or greasier, which isn't ideal for oily or acne-prone skin.
Synthetic origin
It is made from petrochemicals, which some consumers prefer to avoid in favor of plant-based alternatives.
Best for
- People with normal to dry skin who enjoy rich, creamy moisturizers
- Anyone looking for a stable, affordable emulsifier in their routine
Use caution if
- Those with very oily or acne-prone skin who prefer lightweight, gel-based formulas
Usage tips
Safety summary
PEG-90 Stearate is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, though individuals with very oily skin may find it too heavy. Regulatory bodies like the Cosmetic Ingredient Review (CIR) have reviewed PEG stearates and found them safe as used.
Research notes
Studies on PEG stearates indicate they are mild and non-sensitizing. The CIR Expert Panel concluded that PEG stearates are safe in cosmetic formulations. No significant toxicity or irritation has been reported in human patch tests at typical use levels.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission, with no concentration restrictions in leave-on or rinse-off products.
- Common uses
- Creams, Lotions, Cleansers
- Environmental note
- PEG-90 Stearate is not readily biodegradable and is derived from non-renewable petrochemicals, which may be a concern for environmentally conscious consumers.
Good to know
- PEG compounds can sometimes be contaminated with impurities like ethylene oxide during manufacturing, but cosmetic-grade PEG-90 Stearate is purified to safe levels.
- The number '90' indicates the polymer chain length, which influences its water solubility and thickening power.
Common questions
What is PEG-90 Stearate in beauty products?
PEG-90 Stearate is a man-made ingredient that helps oil and water mix together in your skincare products. Think of it as a bridge that keeps the formula from separating into layers. It also makes the product feel thicker and creamier. The 'PEG' part means it has been processed with ethylene oxide to make it water-friendly, and '90' refers to the length of the polymer chain, which affects how it behaves. It is generally considered safe and gentle, but because it is a thicker emulsifier, it might feel a bit heavy on very oily skin.
What does PEG-90 Stearate do in a beauty product?
It reduces the surface tension between oil and water, allowing them to blend into a uniform cream or lotion. Its long polymer chain also adds viscosity, giving products a rich, spreadable texture.
Is PEG-90 Stearate safe for most people?
PEG-90 Stearate is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential, though individuals with very oily skin may find it too heavy. Regulatory bodies like the Cosmetic Ingredient Review (CIR) have reviewed PEG stearates and found them safe as used.
Who should be careful with PEG-90 Stearate?
Those with very oily or acne-prone skin who prefer lightweight, gel-based formulas
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.