Ingredient review
Steareth-3
INCI: STEARETH-3
Steareth-3 is a gentle emulsifier that helps mix water and oil, making creams and lotions smooth and stable.
In plain English
Steareth-3 is a semi-synthetic ingredient made from stearyl alcohol (a fatty alcohol from plant oils) and ethylene oxide. It acts as a bridge between water and oil, allowing them to blend into a stable cream or lotion. In skincare, it helps create a smooth, spreadable texture without leaving a greasy feel. It is considered very mild and unlikely to clog pores or irritate skin.
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
Steareth-3 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 Steareth-3.
- 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
Steareth-3 is an ethoxylated fatty alcohol, meaning it is a stearyl alcohol molecule that has been reacted with about 3 units of ethylene oxide. This process makes it water-friendly while keeping its oil-loving properties, so it can help mix oil and water in a formula.
How it works
In a cosmetic product, Steareth-3 sits at the boundary between oil droplets and water, lowering the surface tension so they stay mixed. This prevents the product from separating into layers and gives it a uniform, creamy consistency. It also helps other ingredients spread evenly on the skin.
Pros
Gentle on skin
Steareth-3 has a very low irritation risk, making it suitable for sensitive skin types and daily use.
Improves product feel
It helps creams and lotions feel smooth and non-greasy, improving the overall user experience.
Cons and cautions
Potential trace impurity
The ethoxylation process can create trace amounts of 1,4-dioxane, a possible carcinogen, though reputable manufacturers purify to safe levels.
Sustainability concerns
Steareth-3 is often derived from palm oil, which can be linked to deforestation unless certified sustainable.
Best for
- People with normal to dry skin
- Anyone using cream-based moisturizers or lotions
Use caution if
- Those with known sensitivity to ethoxylated ingredients (rare)
Usage tips
Safety summary
Steareth-3 is considered safe for use in cosmetics at typical concentrations. The main concern is trace 1,4-dioxane, but levels are tightly regulated and generally below harmful thresholds. It is non-irritating and non-comedogenic for most people.
Research notes
Studies on ethoxylated fatty alcohols show low acute toxicity and skin irritation. The Cosmetic Ingredient Review (CIR) panel has deemed steareth-3 safe as used in rinse-off and leave-on products. No significant human sensitization data is available, but it is widely used without notable adverse reports.
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 concentration of 1,4-dioxane is regulated to be below 10 ppm in the US and 1 ppm in the EU.
- Common uses
- Moisturizers, Cleansers, Hair conditioners
- Environmental note
- Steareth-3 is biodegradable, but its production from palm oil can contribute to deforestation. Look for RSPO-certified palm oil or plant-based alternatives.
Good to know
- Steareth-3 is often used alongside other emulsifiers like Steareth-21 for better stability.
- It is not a preservative; products containing it still need a proper preservation system.
Common questions
What is Steareth-3 in beauty products?
Steareth-3 is a semi-synthetic ingredient made from stearyl alcohol (a fatty alcohol from plant oils) and ethylene oxide. It acts as a bridge between water and oil, allowing them to blend into a stable cream or lotion. In skincare, it helps create a smooth, spreadable texture without leaving a greasy feel. It is considered very mild and unlikely to clog pores or irritate skin.
What does Steareth-3 do in a beauty product?
In a cosmetic product, Steareth-3 sits at the boundary between oil droplets and water, lowering the surface tension so they stay mixed. This prevents the product from separating into layers and gives it a uniform, creamy consistency. It also helps other ingredients spread evenly on the skin.
Is Steareth-3 safe for most people?
Steareth-3 is considered safe for use in cosmetics at typical concentrations. The main concern is trace 1,4-dioxane, but levels are tightly regulated and generally below harmful thresholds. It is non-irritating and non-comedogenic for most people.
Who should be careful with Steareth-3?
Those with known sensitivity to ethoxylated ingredients (rare)
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.