Ingredient review
PEG-5 Castor Oil
INCI: PEG-5 Castor Oil
A gentle emulsifier that helps blend oil and water in cleansers, but may be drying for some skin types.
In plain English
PEG-5 Castor Oil is a modified version of castor oil that has been treated with ethylene oxide to make it water-friendly. It helps mix oil and water in products like cleansers and makeup removers, so they rinse off easily without leaving a greasy residue. While generally mild, it can sometimes strip natural oils if used too frequently.
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-5 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-5 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 derived from castor oil, chemically modified with 5 units of polyethylene glycol (PEG) to improve its water solubility and cleansing properties.
How it works
It acts as a surfactant, reducing the surface tension between oil and water, allowing dirt, makeup, and excess sebum to be lifted from the skin and rinsed away. As an emulsifier, it helps keep oil and water phases blended in a formula.
Pros
Gentle cleansing
Removes oil and makeup without harsh scrubbing, making it suitable for daily use on normal to oily skin.
Good emulsifier
Helps create stable, milky cleansers that rinse cleanly without leaving a heavy residue.
Cons and cautions
Potential for dryness
Frequent use may strip natural oils, leading to tightness or irritation, especially in dry or sensitive skin.
PEG purity concerns
Manufacturing can produce trace amounts of 1,4-dioxane, a potential carcinogen, though reputable brands purify their ingredients.
Best for
- People with oily or combination skin looking for a gentle cleanser
- Those who wear waterproof makeup and need effective removal
Use caution if
- Individuals with very dry or compromised skin barriers
- Anyone with a known sensitivity to PEG compounds
Usage tips
Safety summary
Considered safe at typical cosmetic concentrations, but individuals with sensitive skin or concerns about PEG impurities may prefer alternative surfactants. Look for products from brands that test for 1,4-dioxane purity.
Research notes
Studies indicate PEG-5 Castor Oil is a mild surfactant with low irritation potential, though long-term safety data on PEG compounds remains limited. The Cosmetic Ingredient Review panel has deemed PEGs safe when properly purified.
Common label clues
- Typical concentration
- 1% to 10% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database, with concentration limits in some leave-on products.
- Common uses
- Cleansers, Makeup removers, Shampoos, Conditioners
- Environmental note
- PEG compounds are generally biodegradable, but their production involves ethylene oxide, which is derived from fossil fuels.
Good to know
- PEG-5 Castor Oil is often found in micellar waters and oil cleansers.
- The number '5' refers to the average number of ethylene oxide units added, which affects its water solubility.
Common questions
What is PEG-5 Castor Oil in beauty products?
PEG-5 Castor Oil is a modified version of castor oil that has been treated with ethylene oxide to make it water-friendly. It helps mix oil and water in products like cleansers and makeup removers, so they rinse off easily without leaving a greasy residue. While generally mild, it can sometimes strip natural oils if used too frequently.
What does PEG-5 Castor Oil do in a beauty product?
It acts as a surfactant, reducing the surface tension between oil and water, allowing dirt, makeup, and excess sebum to be lifted from the skin and rinsed away. As an emulsifier, it helps keep oil and water phases blended in a formula.
Is PEG-5 Castor Oil safe for most people?
Considered safe at typical cosmetic concentrations, but individuals with sensitive skin or concerns about PEG impurities may prefer alternative surfactants. Look for products from brands that test for 1,4-dioxane purity.
Who should be careful with PEG-5 Castor Oil?
Individuals with very dry or compromised skin barriers Anyone with a known sensitivity to PEG compounds
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.