Ingredient review
PEG-40 Hydrogenated Castor Oil
INCI: PEG-40 Hydrogenated Castor Oil
PEG-40 is a workhorse emulsifier that helps mix oil and water, but it may cause irritation for sensitive skin at high concentrations.
In plain English
PEG-40 is a synthetic ingredient made by attaching polyethylene glycol (PEG) chains to castor oil. It acts like a bridge between oil and water, allowing them to mix into a stable cream or cleanser. You'll often find it in makeup removers and cleansing oils because it helps rinse away makeup without leaving a greasy film. However, because it can strip the skin's natural oils, it may feel drying or irritating for those with very sensitive or dry 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.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-40 Hydrogenated Castor Oil can be useful, but watch for some irritation potential.
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.
- 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
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 compound created by reacting castor oil with ethylene oxide, resulting in a water-soluble emulsifier.
How it works
PEG-40 reduces the surface tension between oil and water, allowing them to blend into a uniform mixture. In cleansers, it helps lift and suspend makeup and excess oil so they can be rinsed away.
Pros
Excellent makeup remover
PEG-40 dissolves stubborn waterproof makeup and sunscreen without heavy scrubbing, making it ideal for double-cleansing routines.
Improves product texture
It helps create lightweight, non-greasy emulsions that rinse cleanly, leaving skin feeling refreshed rather than oily.
Cons and cautions
Potential irritation
At high concentrations, PEG-40 can strip the skin's natural moisture barrier, leading to tightness, redness, or irritation, especially for sensitive skin types.
Manufacturing impurities
The production process can generate trace amounts of 1,4-dioxane, a potential carcinogen. Reputable brands purify their ingredients to remove it, but it's a concern for some consumers.
Best for
- People with oily or combination skin who need thorough cleansing
- Those who wear heavy makeup or waterproof sunscreen
Use caution if
- Individuals with very dry, compromised, or eczema-prone skin
- Anyone who prefers completely natural or plant-based ingredients
Usage tips
Safety summary
PEG-40 is considered safe for most people when used in rinse-off products at typical concentrations. The main concerns are potential skin irritation for sensitive individuals and trace impurities, which are regulated in many countries.
Research notes
Research shows PEG-40 is an effective emulsifier with low acute toxicity. Studies on skin irritation are mixed, with some reporting mild irritation at high concentrations. The Cosmetic Ingredient Review (CIR) panel has deemed PEG compounds safe as used in cosmetics.
Common label clues
- Typical concentration
- 1–10% in rinse-off products; lower in leave-on
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database, with concentration limits in leave-on products.
- Common uses
- Cleansers, Makeup removers, Fragrance solubilizer
- Environmental note
- PEG compounds are generally biodegradable, but their production relies on fossil fuels. Some environmental groups raise concerns about potential aquatic toxicity at high concentrations.
Good to know
- PEG-40 is often listed as 'PEG-40 Hydrogenated Castor Oil' on ingredient labels.
- It is not the same as PEG-40 Stearate, which is used more in creams and lotions.
Common questions
What is PEG-40 Hydrogenated Castor Oil in beauty products?
PEG-40 is a synthetic ingredient made by attaching polyethylene glycol (PEG) chains to castor oil. It acts like a bridge between oil and water, allowing them to mix into a stable cream or cleanser. You'll often find it in makeup removers and cleansing oils because it helps rinse away makeup without leaving a greasy film. However, because it can strip the skin's natural oils, it may feel drying or irritating for those with very sensitive or dry skin.
What does PEG-40 Hydrogenated Castor Oil do in a beauty product?
PEG-40 reduces the surface tension between oil and water, allowing them to blend into a uniform mixture. In cleansers, it helps lift and suspend makeup and excess oil so they can be rinsed away.
Is PEG-40 Hydrogenated Castor Oil safe for most people?
PEG-40 is considered safe for most people when used in rinse-off products at typical concentrations. The main concerns are potential skin irritation for sensitive individuals and trace impurities, which are regulated in many countries.
Who should be careful with PEG-40 Hydrogenated Castor Oil?
Individuals with very dry, compromised, or eczema-prone skin Anyone who prefers completely natural or plant-based 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.