Ingredient review
Ricinoleth-40
INCI: RICINOLETH-40
Ricinoleth-40 is a gentle emulsifier that helps blend oil and water, but may cause irritation in sensitive skin at high concentrations.
In plain English
Ricinoleth-40 is a modified form of castor oil that has been treated with polyethylene glycol (PEG) to make it water-friendly. In skincare, it acts as a helper ingredient that allows oil and water to mix smoothly, so your cleanser or lotion stays blended and doesn't separate. It also helps dissolve fragrances and essential oils into water-based products. While generally considered safe, it can be mildly irritating for very sensitive skin, especially in high amounts.
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
Ricinoleth-40 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 Ricinoleth-40.
- 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
Ricinoleth-40 is a semi-synthetic ingredient made by reacting castor oil with ethylene oxide (PEG). It belongs to the family of PEGylated oils, commonly used as non-ionic surfactants and emulsifiers in cosmetics.
How it works
Ricinoleth-40 reduces the surface tension between oil and water, allowing them to form a stable emulsion. It also helps solubilize oily ingredients like fragrances and essential oils into water-based formulas, improving product texture and clarity.
Pros
Effective emulsifier
Ricinoleth-40 helps create stable, smooth emulsions so your products don't separate, improving user experience.
Versatile solubilizer
It can dissolve oils and fragrances into water-based formulas, allowing for clear, appealing products like micellar waters.
Cons and cautions
Mild irritation risk
At higher concentrations, Ricinoleth-40 may cause stinging or irritation, especially on sensitive or damaged skin.
PEG-related concerns
As a PEG derivative, it may contain trace amounts of 1,4-dioxane, a potential contaminant, though levels are typically low in well-manufactured products.
Best for
- People with normal to oily skin looking for effective cleansers
- Those who use fragranced products and need stable solubilization
Use caution if
- Individuals with very sensitive or compromised skin
- Those avoiding PEG-derived ingredients due to ethical or purity concerns
Usage tips
Safety summary
Ricinoleth-40 is generally safe for most skin types when used at typical concentrations. However, it can be mildly irritating for sensitive skin, and trace contaminants from the ethoxylation process are a consideration for purity-conscious consumers.
Research notes
The Cosmetic Ingredient Review (CIR) panel has evaluated PEGylated castor oil derivatives and found them safe for cosmetic use at concentrations up to 100% in rinse-off and up to 10% in leave-on products, with low irritation potential in most cases.
Common label clues
- Typical concentration
- 0.5% to 5% in rinse-off products; lower in leave-on formulations
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions, with concentration limits recommended by industry safety panels.
- Common uses
- Cleansers, Shampoos, Fragrance solubilization, Makeup removers
- Environmental note
- As a semi-synthetic ingredient, its biodegradability is moderate; PEG derivatives can persist in water systems, though Ricinoleth-40 is less concerning than some other ethoxylates.
Good to know
- Ricinoleth-40 is often used to solubilize essential oils in fragrance formulations.
- It is considered safe by the Cosmetic Ingredient Review (CIR) panel at typical use levels.
Common questions
What is Ricinoleth-40 in beauty products?
Ricinoleth-40 is a modified form of castor oil that has been treated with polyethylene glycol (PEG) to make it water-friendly. In skincare, it acts as a helper ingredient that allows oil and water to mix smoothly, so your cleanser or lotion stays blended and doesn't separate. It also helps dissolve fragrances and essential oils into water-based products. While generally considered safe, it can be mildly irritating for very sensitive skin, especially in high amounts.
What does Ricinoleth-40 do in a beauty product?
Ricinoleth-40 reduces the surface tension between oil and water, allowing them to form a stable emulsion. It also helps solubilize oily ingredients like fragrances and essential oils into water-based formulas, improving product texture and clarity.
Is Ricinoleth-40 safe for most people?
Ricinoleth-40 is generally safe for most skin types when used at typical concentrations. However, it can be mildly irritating for sensitive skin, and trace contaminants from the ethoxylation process are a consideration for purity-conscious consumers.
Who should be careful with Ricinoleth-40?
Individuals with very sensitive or compromised skin Those avoiding PEG-derived ingredients due to ethical or purity concerns
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.