Ingredient review
PEG-40 Hydrogenated Castor Oil Triisostearate
INCI: PEG-40 HYDROGENATED CASTOR OIL TRIISOSTEARATE
A gentle emulsifier that helps mix oil and water in your products, but may feel heavy on very oily skin.
In plain English
This ingredient is a modified castor oil that has been processed with PEG (polyethylene glycol) to make it water-friendly. It acts like a bridge between oil and water, allowing them to blend smoothly in creams, lotions, and cleansers. Think of it as a helper that keeps your product from separating into layers. It also has mild cleansing properties, making it useful in makeup removers.
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
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-40 Hydrogenated Castor Oil Triisostearate 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 Hydrogenated Castor Oil Triisostearate.
- 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
A semi-synthetic emulsifier created by reacting hydrogenated castor oil with PEG-40 and triisostearic acid. It is a waxy, yellowish solid at room temperature and is widely used in cosmetics to stabilize oil-in-water emulsions.
How it works
Its molecular structure has both water-loving (hydrophilic) and oil-loving (lipophilic) parts. When added to a formula, it surrounds oil droplets and suspends them in water, creating a stable, creamy texture. This prevents separation and ensures a uniform application.
Pros
Gentle on skin
Has a low irritation risk, making it suitable for sensitive skin and daily use in cleansers and moisturizers.
Effective emulsifier
Stabilizes oil-and-water blends, giving your products a smooth, consistent texture that doesn't separate over time.
Cons and cautions
Can feel heavy
On very oily or acne-prone skin, it may leave a slight greasy or waxy feel, especially in leave-on products.
Processing concerns
The PEG process can introduce impurities like 1,4-dioxane if not properly purified, though reputable manufacturers control for this.
Best for
- People with normal to dry skin who use creamy cleansers or lotions
- Anyone looking for a gentle, non-stripping makeup remover
Use caution if
- Those with very oily or acne-prone skin may prefer lighter emulsifiers like Polysorbate 20
Usage tips
Safety summary
Generally recognized as safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. As with any PEG compound, purity matters—choose products from reputable brands that follow good manufacturing practices.
Research notes
The Cosmetic Ingredient Review (CIR) panel has evaluated PEG derivatives and found them safe for use in cosmetics. No significant human or animal studies specifically on this ingredient are widely published, but its safety profile is inferred from related PEG compounds.
Common label clues
- Typical concentration
- 1% to 5% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. The CIR panel has reviewed it and found it safe as used.
- Common uses
- Cleansers, Makeup removers, Lotions, Creams, Sunscreens
- Environmental note
- Derived from castor oil, a renewable plant source, but the PEG component is synthetic and may have moderate biodegradability.
Good to know
- PEG-40 Hydrogenated Castor Oil Triisostearate is often used in combination with other emulsifiers to fine-tune texture.
- It is considered safe by the Cosmetic Ingredient Review (CIR) panel at typical use concentrations.
Common questions
What is PEG-40 Hydrogenated Castor Oil Triisostearate in beauty products?
This ingredient is a modified castor oil that has been processed with PEG (polyethylene glycol) to make it water-friendly. It acts like a bridge between oil and water, allowing them to blend smoothly in creams, lotions, and cleansers. Think of it as a helper that keeps your product from separating into layers. It also has mild cleansing properties, making it useful in makeup removers.
What does PEG-40 Hydrogenated Castor Oil Triisostearate do in a beauty product?
Its molecular structure has both water-loving (hydrophilic) and oil-loving (lipophilic) parts. When added to a formula, it surrounds oil droplets and suspends them in water, creating a stable, creamy texture. This prevents separation and ensures a uniform application.
Is PEG-40 Hydrogenated Castor Oil Triisostearate safe for most people?
Generally recognized as safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. As with any PEG compound, purity matters—choose products from reputable brands that follow good manufacturing practices.
Who should be careful with PEG-40 Hydrogenated Castor Oil Triisostearate?
Those with very oily or acne-prone skin may prefer lighter emulsifiers like Polysorbate 20
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.