Ingredient review
PEG-3 Castor Oil
INCI: PEG-3 Castor Oil
A gentle, castor-oil-based emulsifier that helps mix water and oil without stripping the skin.
In plain English
PEG-3 Castor Oil is a modified version of castor oil that has been processed with ethylene oxide to make it water-friendly. In a skincare product, it acts like a bridge between oil and water, allowing them to blend into a smooth cream or lotion. It also helps cleanse the skin by lifting away dirt and makeup without leaving a greasy residue. Because it's derived from castor oil, it's considered relatively mild and non-irritating for most skin types.
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-3 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-3 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
A semi-synthetic ingredient made by reacting castor oil with ethylene oxide. The 'PEG-3' indicates the average number of ethylene oxide units attached, which gives the oil water-soluble properties while retaining its mild cleansing ability.
How it works
In a formula, PEG-3 Castor Oil reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps create creamy textures and helps rinse away oil-based impurities when used in cleansers or makeup removers.
Pros
Gentle on skin
Derived from castor oil, it cleanses without stripping the skin's natural moisture barrier, making it suitable for daily use.
Versatile emulsifier
Works well in both rinse-off and leave-on products, helping create smooth, stable textures that feel pleasant on the skin.
Cons and cautions
Potential trace impurity
During manufacturing, trace amounts of 1,4-dioxane can form. Reputable brands ensure levels are within safe limits set by regulators.
Not for water-free formulas
This ingredient requires water to function as an emulsifier, so it won't work in anhydrous (waterless) products.
Best for
- People with normal to dry skin looking for a gentle cleanser
- Those who prefer plant-derived emulsifiers in their routine
Use caution if
- Individuals with a known allergy to castor oil or PEG compounds (rare)
Usage tips
Safety summary
PEG-3 Castor Oil is considered safe for use in cosmetics at typical concentrations. The main safety concern is the potential formation of 1,4-dioxane, a byproduct that is strictly regulated. When sourced from reputable manufacturers, the risk is minimal.
Research notes
Studies on PEG-3 Castor Oil are limited, but it is widely used in cosmetics with a long history of safe use. The Cosmetic Ingredient Review (CIR) panel has evaluated similar PEG castor oil derivatives and found them safe as used.
Common label clues
- Typical concentration
- 1–5% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission. Manufacturers must ensure 1,4-dioxane levels are below 10 ppm in finished products.
- Common uses
- Cleansers, Makeup removers, Lotions, Creams
- Environmental note
- Castor oil is a renewable plant resource, but the ethoxylation process involves synthetic chemistry. Biodegradability is moderate.
Good to know
- PEG-3 Castor Oil is often used in micellar waters and cleansing balms for its ability to dissolve makeup without irritation.
- The 'PEG' number (3) indicates a low degree of ethoxylation, which generally means milder cleansing compared to higher PEG numbers.
Common questions
What is PEG-3 Castor Oil in beauty products?
PEG-3 Castor Oil is a modified version of castor oil that has been processed with ethylene oxide to make it water-friendly. In a skincare product, it acts like a bridge between oil and water, allowing them to blend into a smooth cream or lotion. It also helps cleanse the skin by lifting away dirt and makeup without leaving a greasy residue. Because it's derived from castor oil, it's considered relatively mild and non-irritating for most skin types.
What does PEG-3 Castor Oil do in a beauty product?
In a formula, PEG-3 Castor Oil reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps create creamy textures and helps rinse away oil-based impurities when used in cleansers or makeup removers.
Is PEG-3 Castor Oil safe for most people?
PEG-3 Castor Oil is considered safe for use in cosmetics at typical concentrations. The main safety concern is the potential formation of 1,4-dioxane, a byproduct that is strictly regulated. When sourced from reputable manufacturers, the risk is minimal.
Who should be careful with PEG-3 Castor Oil?
Individuals with a known allergy to castor oil or 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.