Ingredient review
PEG-9 Castor Oil
INCI: PEG-9 Castor Oil
A gentle emulsifier that helps mix oil and water, commonly found in cleansers and shampoos, with a low risk of irritation.
In plain English
PEG-9 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 as a helper ingredient that allows oil and water to blend together smoothly, which is why you'll find it in many cleansers and makeup removers. It also helps other ingredients spread evenly on your skin and can boost the foaming action of cleansers. Because it's derived from castor oil, it's generally considered gentle 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-9 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-9 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-9 Castor Oil is a semi-synthetic ingredient created by reacting castor oil with 9 units of ethylene oxide. This process makes the oil water-soluble, turning it into an effective emulsifier and surfactant.
How it works
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers remove makeup and excess oil while rinsing away easily with water.
Pros
Effective emulsifier
Helps create stable, creamy cleansers that remove makeup and sunscreen without leaving a greasy residue.
Low irritation potential
Generally well-tolerated by most skin types, including sensitive skin, when used at typical concentrations.
Cons and cautions
Semi-synthetic origin
Not suitable for those who prefer exclusively natural or organic ingredients, as it undergoes chemical processing.
Potential impurities
The ethoxylation process can produce trace amounts of 1,4-dioxane, a contaminant of concern, though levels are typically low in well-manufactured products.
Best for
- People with normal to oily skin looking for gentle cleansers
- Those who use makeup removers or micellar waters
Use caution if
- Individuals with known sensitivity to PEG compounds
- Those seeking 100% natural or organic formulations
Usage tips
Safety summary
PEG-9 Castor Oil is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but reputable manufacturers control for this. It has low irritation and comedogenic risk.
Research notes
Studies and safety reviews by the Cosmetic Ingredient Review (CIR) panel have concluded that PEG derivatives of castor oil are safe in cosmetic formulations when used as directed. No significant skin sensitization or toxicity has been reported.
Common label clues
- Typical concentration
- 1–5% in rinse-off products; lower in leave-on products
- Regulatory status
- Approved for use in cosmetics by the FDA and EU Cosmetics Regulation. Manufacturers are encouraged to limit 1,4-dioxane levels to safe thresholds.
- Common uses
- Cleansers, Shampoos, Body washes, Makeup removers
- Environmental note
- PEG-9 Castor Oil is biodegradable, but the ethoxylation process has an environmental footprint. Some brands choose PEG-free alternatives for sustainability reasons.
Good to know
- PEG-9 Castor Oil is often used as a solubilizer for essential oils in water-based products.
- It is considered biodegradable and is widely used in personal care products globally.
Common questions
What is PEG-9 Castor Oil in beauty products?
PEG-9 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 as a helper ingredient that allows oil and water to blend together smoothly, which is why you'll find it in many cleansers and makeup removers. It also helps other ingredients spread evenly on your skin and can boost the foaming action of cleansers. Because it's derived from castor oil, it's generally considered gentle and non-irritating for most skin types.
What does PEG-9 Castor Oil do in a beauty product?
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers remove makeup and excess oil while rinsing away easily with water.
Is PEG-9 Castor Oil safe for most people?
PEG-9 Castor Oil is considered safe for use in cosmetics at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but reputable manufacturers control for this. It has low irritation and comedogenic risk.
Who should be careful with PEG-9 Castor Oil?
Individuals with known sensitivity to PEG compounds Those seeking 100% natural or organic formulations
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.