Ingredient review
Ceteareth-5 Phosphate
INCI: Ceteareth-5 Phosphate
A gentle, phosphate-based emulsifier that helps blend water and oil without stripping the skin, making it a good choice for sensitive skin formulations.
In plain English
Ceteareth-5 Phosphate is a mild cleansing and mixing ingredient used in skincare to help water and oil combine into a smooth cream or lotion. It's made from fatty alcohols (from plant or synthetic sources) and phosphoric acid, and it's designed to be gentle on the skin, so it won't leave your face feeling tight or dry after washing.
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-5 Phosphate 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-5 Phosphate.
- 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-5 Phosphate is a semi-synthetic surfactant and emulsifier. It belongs to the phosphate ester family, which are known for being milder than traditional sulfates. It is created by reacting cetearyl alcohol (a blend of fatty alcohols) with phosphoric acid and ethylene oxide, resulting in a molecule that can help mix oil and water.
How it works
In a cosmetic product, Ceteareth-5 Phosphate sits at the boundary between oil and water droplets, reducing surface tension so they blend into a stable emulsion. This allows creams and lotions to have a smooth, uniform texture. As a surfactant, it also helps lift dirt and oil from the skin's surface, but because it's a phosphate ester, it is much less likely to strip the skin's natural moisture barrier compared to harsher cleansers like sodium lauryl sulfate.
Pros
Very gentle on skin
Unlike harsh sulfates, Ceteareth-5 Phosphate cleanses without stripping the skin's natural oils, making it ideal for daily use on sensitive or dry skin.
Versatile emulsifier
It helps create smooth, stable creams and lotions that don't separate, improving product texture and shelf life.
Cons and cautions
Potential trace contaminant
The manufacturing process (ethoxylation) can produce trace amounts of 1,4-dioxane, a possible carcinogen. However, reputable brands purify their ingredients to keep levels well below safety limits.
Sustainability concerns
Ceteareth-5 Phosphate is often derived from palm oil, which can be linked to deforestation. Look for brands that use certified sustainable palm oil or plant-based alternatives.
Best for
- People with dry or sensitive skin looking for a mild cleanser
- Anyone using cream or lotion formulations that need a stable, non-irritating emulsifier
Use caution if
- Individuals with known allergies to phosphate esters (rare)
- Those seeking completely natural or plant-only ingredients (it is semi-synthetic)
Usage tips
Safety summary
Ceteareth-5 Phosphate is considered safe for use in cosmetics at typical concentrations. The main concern is trace 1,4-dioxane from manufacturing, but reputable suppliers purify the ingredient to meet safety standards. It has low irritation and comedogenic potential.
Research notes
Research on phosphate ester surfactants, including Ceteareth-5 Phosphate, indicates they are mild and well-tolerated. The Cosmetic Ingredient Review (CIR) has assessed similar ingredients and found them safe. No specific large-scale human studies on this exact ingredient were found, but its safety profile is supported by its chemical class and regulatory approvals.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the EU, US, and many other regions. The Cosmetic Ingredient Review (CIR) panel has reviewed related phosphate esters and found them safe at typical concentrations.
- Common uses
- Cleansers, Lotions, Creams, Makeup removers
- Environmental note
- The environmental impact depends on sourcing. If derived from palm oil, look for RSPO-certified sustainable palm oil. The ethoxylation process also has an energy footprint, but the ingredient itself is biodegradable.
Good to know
- Ceteareth-5 Phosphate is often listed near the middle or end of an ingredient list because it is used in small amounts.
- It is considered a 'phosphate ester' surfactant, which is a class known for being milder than sulfates.
Common questions
What is Ceteareth-5 Phosphate in beauty products?
Ceteareth-5 Phosphate is a mild cleansing and mixing ingredient used in skincare to help water and oil combine into a smooth cream or lotion. It's made from fatty alcohols (from plant or synthetic sources) and phosphoric acid, and it's designed to be gentle on the skin, so it won't leave your face feeling tight or dry after washing.
What does Ceteareth-5 Phosphate do in a beauty product?
In a cosmetic product, Ceteareth-5 Phosphate sits at the boundary between oil and water droplets, reducing surface tension so they blend into a stable emulsion. This allows creams and lotions to have a smooth, uniform texture. As a surfactant, it also helps lift dirt and oil from the skin's surface, but because it's a phosphate ester, it is much less likely to strip the skin's natural moisture barrier compared to harsher cleansers like sodium lauryl sulfate.
Is Ceteareth-5 Phosphate safe for most people?
Ceteareth-5 Phosphate is considered safe for use in cosmetics at typical concentrations. The main concern is trace 1,4-dioxane from manufacturing, but reputable suppliers purify the ingredient to meet safety standards. It has low irritation and comedogenic potential.
Who should be careful with Ceteareth-5 Phosphate?
Individuals with known allergies to phosphate esters (rare) Those seeking completely natural or plant-only ingredients (it is semi-synthetic)
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.