Ingredient review
PEG-40 Sorbitan Diisostearate
INCI: PEG-40 SORBITAN DIISOSTEARATE
A gentle, synthetic emulsifier that helps create stable, creamy formulas without common irritation concerns.
In plain English
PEG-40 Sorbitan Diisostearate is a man-made ingredient that acts like a bridge between oil and water. In your moisturizer or cleanser, it stops the oil and water from separating, so the product stays smooth and creamy. It's part of a family of PEG (polyethylene glycol) compounds that are widely used because they are mild and effective.
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-40 Sorbitan Diisostearate 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-40 Sorbitan Diisostearate.
- 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-40 Sorbitan Diisostearate is a synthetic emulsifier created by reacting sorbitan (a sugar alcohol) with diisostearic acid and then adding 40 units of polyethylene glycol (PEG). It belongs to the sorbitan ester family and is valued for its ability to stabilize oil-in-water emulsions.
How it works
In a cosmetic formula, this ingredient sits at the boundary between oil droplets and water, reducing surface tension so the two phases mix evenly. This prevents separation over time and gives the product a uniform, pleasant texture. It also helps other ingredients spread smoothly on the skin.
Pros
Excellent emulsion stabilizer
Keeps oil and water mixed in creams and lotions, preventing separation and ensuring a consistent texture from first use to last.
Low irritation potential
Rated as low-irritation and low-comedogenic, making it suitable for most skin types, including sensitive skin.
Cons and cautions
Synthetic origin
Derived from petroleum-based ethylene oxide, which may be a concern for those seeking natural or 'clean' formulations.
Potential trace impurities
PEG compounds can contain trace amounts of 1,4-dioxane (a possible carcinogen) if not properly purified; however, reputable manufacturers follow strict purification standards.
Best for
- Anyone using lotions, creams, or cleansers who wants a stable, non-greasy texture
- People with normal to dry skin looking for gentle emulsifiers
Use caution if
- Those who strictly avoid all synthetic or PEG-based ingredients
- Individuals with known sensitivity to PEG compounds (rare)
Usage tips
Safety summary
PEG-40 Sorbitan Diisostearate is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but modern manufacturing processes reduce this to trace levels well below safety limits. It is non-irritating and non-comedogenic for most people.
Research notes
The Cosmetic Ingredient Review (CIR) panel has reviewed PEG sorbitan esters and found them safe in current usage patterns. No significant human or animal studies indicate toxicity at cosmetic exposure levels. The ingredient is widely used globally with a strong safety record.
Common label clues
- Typical concentration
- 1–5% in leave-on products; up to 10% in rinse-off products
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database. The Cosmetic Ingredient Review (CIR) panel has deemed PEG compounds safe as used in cosmetics when properly purified.
- Common uses
- Moisturizers, Cleansers, Sunscreens, Makeup removers
- Environmental note
- PEG-40 Sorbitan Diisostearate is not readily biodegradable and may persist in aquatic environments. Its production relies on fossil fuels.
Good to know
- PEG numbers (like 40) indicate the length of the polyethylene glycol chain, which affects water solubility and mildness.
- This ingredient is often used in 'micellar' cleansing waters because of its gentle surfactant properties.
Common questions
What is PEG-40 Sorbitan Diisostearate in beauty products?
PEG-40 Sorbitan Diisostearate is a man-made ingredient that acts like a bridge between oil and water. In your moisturizer or cleanser, it stops the oil and water from separating, so the product stays smooth and creamy. It's part of a family of PEG (polyethylene glycol) compounds that are widely used because they are mild and effective.
What does PEG-40 Sorbitan Diisostearate do in a beauty product?
In a cosmetic formula, this ingredient sits at the boundary between oil droplets and water, reducing surface tension so the two phases mix evenly. This prevents separation over time and gives the product a uniform, pleasant texture. It also helps other ingredients spread smoothly on the skin.
Is PEG-40 Sorbitan Diisostearate safe for most people?
PEG-40 Sorbitan Diisostearate is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but modern manufacturing processes reduce this to trace levels well below safety limits. It is non-irritating and non-comedogenic for most people.
Who should be careful with PEG-40 Sorbitan Diisostearate?
Those who strictly avoid all synthetic or PEG-based ingredients 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.