Ingredient review
Ceteareth-55
INCI: CETEARETH-55
Ceteareth-55 is a reliable emulsifier that keeps creams and lotions smooth, but it's synthetic and may be a minor concern for very sensitive skin.
In plain English
Ceteareth-55 is a man-made ingredient that helps oil and water stay mixed together in products like moisturizers and cleansers. Without it, your lotion would separate into a watery layer and an oily layer. It's part of a family of ingredients called ceteareths, which are made from fatty alcohols and ethylene oxide. While it's generally considered safe, some people prefer to avoid ingredients processed with ethylene oxide due to trace impurities.
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
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Ceteareth-55 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 Ceteareth-55.
- 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
Ceteareth-55 is a synthetic emulsifier derived from cetearyl alcohol (a fatty alcohol from plant or petroleum sources) and ethylene oxide. The number 55 refers to the average number of ethylene oxide units in the molecule, which makes it water-loving and effective at stabilizing oil-in-water emulsions.
How it works
In a cosmetic product, Ceteareth-55 sits at the boundary between oil and water droplets, reducing surface tension so they blend into a stable, creamy emulsion. This prevents separation and gives the product a smooth, uniform texture that spreads easily on skin.
Pros
Excellent emulsifier
Ceteareth-55 creates stable, creamy emulsions that keep your lotion from separating, so you get a consistent product every time.
Gentle for most skin
It has a low irritation and comedogenic risk, making it suitable for normal, dry, and combination skin types.
Cons and cautions
Synthetic origin
It's made from petroleum-derived ethylene oxide, which may be a turn-off if you prefer plant-based or natural ingredients.
Potential trace impurities
The manufacturing process can leave trace amounts of 1,4-dioxane, a possible carcinogen, though levels are tightly regulated and generally very low.
Best for
- Anyone using standard moisturizers or cleansers
- People who want a reliable, well-tested emulsifier
Use caution if
- Those seeking 100% natural or organic formulations
- Individuals with known sensitivity to ethoxylated ingredients
Usage tips
Safety summary
Ceteareth-55 is considered safe for use in cosmetics at typical concentrations. The main concern is trace contamination with 1,4-dioxane, but regulatory limits keep levels very low. It has low irritation and comedogenic potential.
Research notes
The Cosmetic Ingredient Review (CIR) panel reviewed ceteareth compounds and concluded they are safe in current use patterns. No significant human or animal studies show harm at cosmetic levels.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission. The Cosmetic Ingredient Review (CIR) panel has deemed ceteareth-type ingredients safe as used in cosmetics.
- Common uses
- Moisturizers, Cleansers, Sunscreens, Hair conditioners
- Environmental note
- Ceteareth-55 is synthetic and not readily biodegradable. Its production involves ethylene oxide, which has environmental concerns related to fossil fuel extraction.
Good to know
- The number 55 indicates a high degree of ethoxylation, making it more water-soluble than lower-numbered ceteareths.
- It's often used alongside cetearyl alcohol in commercial emulsifying waxes.
Common questions
What is Ceteareth-55 in beauty products?
Ceteareth-55 is a man-made ingredient that helps oil and water stay mixed together in products like moisturizers and cleansers. Without it, your lotion would separate into a watery layer and an oily layer. It's part of a family of ingredients called ceteareths, which are made from fatty alcohols and ethylene oxide. While it's generally considered safe, some people prefer to avoid ingredients processed with ethylene oxide due to trace impurities.
What does Ceteareth-55 do in a beauty product?
In a cosmetic product, Ceteareth-55 sits at the boundary between oil and water droplets, reducing surface tension so they blend into a stable, creamy emulsion. This prevents separation and gives the product a smooth, uniform texture that spreads easily on skin.
Is Ceteareth-55 safe for most people?
Ceteareth-55 is considered safe for use in cosmetics at typical concentrations. The main concern is trace contamination with 1,4-dioxane, but regulatory limits keep levels very low. It has low irritation and comedogenic potential.
Who should be careful with Ceteareth-55?
Those seeking 100% natural or organic formulations Individuals with known sensitivity to 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.