Ingredient review
PEG-100 Castor Oil
INCI: PEG-100 Castor Oil
PEG-100 Castor Oil is a reliable emulsifier that helps mix oil and water in cleansers and creams, but it may not suit those avoiding ethoxylated ingredients.
In plain English
PEG-100 Castor Oil is a modified version of castor oil that has been treated with ethylene oxide to make it water-friendly. In skincare, it acts like a bridge between oil and water, allowing them to blend into a smooth cream or lotion. It also helps lift makeup and sunscreen from the skin during cleansing. Because it's ethoxylated, it may contain trace amounts of 1,4-dioxane, a potential impurity, though reputable brands purify it to safe levels.
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-100 Castor Oil 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-100 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
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-100 Castor Oil is a semi-synthetic ingredient made by reacting castor oil with 100 units of ethylene oxide. This process creates a water-soluble emulsifier that can stabilize oil-in-water emulsions.
How it works
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. In cleansers, it helps dissolve and rinse away oily residues like makeup and sebum.
Pros
Effective emulsifier
It reliably blends oil and water, giving creams and lotions a smooth, uniform texture that feels pleasant on the skin.
Gentle cleanser
In rinse-off products, it removes makeup and sunscreen without stripping the skin's natural moisture barrier.
Cons and cautions
Ethoxylation concerns
The manufacturing process can leave trace amounts of 1,4-dioxane, a potential carcinogen, though levels are regulated and typically very low in finished products.
Not natural
Despite being derived from castor oil, it undergoes chemical modification, so it won't appeal to those seeking purely natural or organic formulations.
Best for
- People who use oil-based makeup or sunscreen
- Those looking for gentle, non-stripping cleansers
Use caution if
- Individuals with known sensitivity to PEG compounds
- Those seeking 100% natural or non-ethoxylated ingredients
Usage tips
Safety summary
PEG-100 Castor Oil is considered low-risk for irritation and comedogenicity. The main safety concern is potential contamination with 1,4-dioxane, but reputable suppliers purify the ingredient to meet safety standards. Overall, it is safe for most people in typical cosmetic concentrations.
Research notes
The Cosmetic Ingredient Review (CIR) panel evaluated PEG castor oil derivatives and concluded they are safe as used in cosmetics. No significant human or animal studies indicate toxicity at typical exposure levels. The European Chemicals Agency (ECHA) also lists it as safe with appropriate purification.
Common label clues
- Typical concentration
- 1–5% in most leave-on products; up to 10% in rinse-off cleansers
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. The CIR panel has deemed it safe at concentrations up to 100% in rinse-off products and up to 5% in leave-on products.
- Common uses
- Cleansers, Makeup removers, Lotions, Creams
- Environmental note
- PEG compounds can be slow to biodegrade, but they are not considered bioaccumulative. Manufacturers are encouraged to use purification steps to minimize 1,4-dioxane release.
Good to know
- PEG-100 Castor Oil is often listed alongside other PEG compounds in ingredient lists.
- It is considered safe by the Cosmetic Ingredient Review (CIR) panel at typical use levels.
Common questions
What is PEG-100 Castor Oil in beauty products?
PEG-100 Castor Oil is a modified version of castor oil that has been treated with ethylene oxide to make it water-friendly. In skincare, it acts like a bridge between oil and water, allowing them to blend into a smooth cream or lotion. It also helps lift makeup and sunscreen from the skin during cleansing. Because it's ethoxylated, it may contain trace amounts of 1,4-dioxane, a potential impurity, though reputable brands purify it to safe levels.
What does PEG-100 Castor Oil do in a beauty product?
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. In cleansers, it helps dissolve and rinse away oily residues like makeup and sebum.
Is PEG-100 Castor Oil safe for most people?
PEG-100 Castor Oil is considered low-risk for irritation and comedogenicity. The main safety concern is potential contamination with 1,4-dioxane, but reputable suppliers purify the ingredient to meet safety standards. Overall, it is safe for most people in typical cosmetic concentrations.
Who should be careful with PEG-100 Castor Oil?
Individuals with known sensitivity to PEG compounds Those seeking 100% natural or non-ethoxylated 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.