Ingredient review
Ceteareth-100
INCI: Ceteareth-100
Ceteareth-100 is a reliable emulsifier that helps blend oil and water in creams and lotions, but it is a PEG compound, which raises mild concerns about potential impurities.
In plain English
Ceteareth-100 is a helper ingredient that keeps oil and water mixed together in your lotions and creams so they don't separate. It belongs to a family of ingredients called PEGs (polyethylene glycols), which are made by adding ethylene oxide to fatty alcohols from coconut or palm oil. While it's generally considered safe, some people prefer to avoid PEGs due to concerns about manufacturing impurities like 1,4-dioxane, though reputable brands purify their ingredients to remove these traces.
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
Ceteareth-100 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-100.
- 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-100 is a semi-synthetic emulsifier created by reacting cetearyl alcohol (a blend of fatty alcohols from plant oils) with 100 units of ethylene oxide. This process makes it water-soluble and able to stabilize oil-in-water emulsions.
How it works
In a cosmetic formula, Ceteareth-100 sits at the boundary between oil and water droplets, reducing surface tension so they mix into a stable, creamy emulsion. This prevents your product from separating into watery and oily layers, giving it a smooth, uniform texture.
Pros
Effective emulsifier
Ceteareth-100 reliably blends oil and water, giving creams and lotions a smooth, stable texture that doesn't separate over time.
Low irritation potential
At typical use levels, it has a low risk of skin irritation, making it suitable for most skin types in rinse-off and leave-on products.
Cons and cautions
PEG-related concerns
As a PEG compound, it may contain trace impurities like 1,4-dioxane from manufacturing, though reputable brands purify to safe levels.
Not natural
It is semi-synthetic and derived from ethylene oxide, which doesn't align with clean or natural beauty preferences.
Best for
- People using standard moisturizers and creams who want a stable, affordable formula
- Those with normal to combination skin looking for a reliable emulsifier
Use caution if
- Individuals with known sensitivity to PEG compounds
- Those seeking fully natural or organic skincare formulations
Usage tips
Safety summary
Ceteareth-100 is considered safe for use in cosmetics at typical concentrations. The main safety discussion centers on potential 1,4-dioxane contamination, which is regulated and minimized through purification. The Cosmetic Ingredient Review (CIR) panel has deemed similar PEG compounds safe as used.
Research notes
Research on Ceteareth-100 specifically is limited, but the broader class of PEG ethers has been reviewed by the CIR panel, concluding they are safe in cosmetic formulations when manufactured to purity standards. No significant skin sensitization or irritation has been reported at typical use levels.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission, with concentration limits generally not specified due to its safe history of use.
- Common uses
- Moisturizers, Cleansers, Lotions, Creams
- Environmental note
- Derived from plant-based fatty alcohols (coconut or palm oil) but involves synthetic processing. Palm oil sourcing may raise sustainability concerns unless certified sustainable.
Good to know
- The number '100' refers to the average number of ethylene oxide units added, which affects its water solubility and emulsifying strength.
- Ceteareth-100 is often used alongside cetearyl alcohol in commercial emulsifying waxes.
Common questions
What is Ceteareth-100 in beauty products?
Ceteareth-100 is a helper ingredient that keeps oil and water mixed together in your lotions and creams so they don't separate. It belongs to a family of ingredients called PEGs (polyethylene glycols), which are made by adding ethylene oxide to fatty alcohols from coconut or palm oil. While it's generally considered safe, some people prefer to avoid PEGs due to concerns about manufacturing impurities like 1,4-dioxane, though reputable brands purify their ingredients to remove these traces.
What does Ceteareth-100 do in a beauty product?
In a cosmetic formula, Ceteareth-100 sits at the boundary between oil and water droplets, reducing surface tension so they mix into a stable, creamy emulsion. This prevents your product from separating into watery and oily layers, giving it a smooth, uniform texture.
Is Ceteareth-100 safe for most people?
Ceteareth-100 is considered safe for use in cosmetics at typical concentrations. The main safety discussion centers on potential 1,4-dioxane contamination, which is regulated and minimized through purification. The Cosmetic Ingredient Review (CIR) panel has deemed similar PEG compounds safe as used.
Who should be careful with Ceteareth-100?
Individuals with known sensitivity to PEG compounds Those seeking fully natural or organic skincare 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.