Ingredient review
Steareth-15
INCI: STEARETH-15
Steareth-15 is a reliable emulsifier that helps create smooth, stable creams and lotions, but it is synthetic and may not appeal to those seeking natural ingredients.
In plain English
Steareth-15 is a man-made ingredient that helps oil and water mix together in your skincare products. Think of it as a peacekeeper that stops your lotion from separating into oily and watery layers. It is made from a fatty alcohol (stearyl alcohol) combined with ethylene oxide, a process that creates a gentle, water-soluble emulsifier. You will find it in many creams, cleansers, and moisturizers where it also helps spread the product evenly on your 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
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Steareth-15 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-15.
- 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-15 is a polyethylene glycol (PEG) ether of stearyl alcohol, containing an average of 15 ethylene oxide units. It belongs to the steareth family of emulsifiers, which are widely used in cosmetics for their ability to stabilize oil-in-water emulsions.
How it works
In a cosmetic formula, Steareth-15 sits at the boundary between oil and water droplets, reducing surface tension so they can blend into a stable, uniform cream or lotion. It also helps other ingredients spread smoothly and can act as a mild cleansing agent in rinse-off products.
Pros
Effective emulsifier
Steareth-15 reliably blends oil and water, preventing separation and giving your creams a smooth, uniform texture.
Low irritation potential
It is considered gentle on skin and is unlikely to cause stinging or redness, making it suitable for most skin types.
Cons and cautions
Synthetic origin
As a PEG compound, it is manufactured from petrochemicals, which may not align with natural or minimalist skincare preferences.
Potential trace impurities
During production, trace amounts of 1,4-dioxane (a possible contaminant) can form, though reputable manufacturers purify to safe levels.
Best for
- People who use conventional creams and lotions and want a stable, consistent texture
- Those with normal to dry skin looking for a gentle emulsifier
Use caution if
- Individuals who strictly avoid synthetic or PEG-based ingredients in their skincare routine
Usage tips
Safety summary
Steareth-15 is considered safe for cosmetic use at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but industry standards and regulations keep levels very low. It is not a known irritant or sensitizer for most people.
Research notes
The Cosmetic Ingredient Review (CIR) panel has evaluated steareth ingredients and found them safe as used. Studies indicate low acute toxicity and no significant skin irritation or sensitization. Research on PEG compounds generally supports their safety when properly purified.
Common label clues
- Typical concentration
- 1–5% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (CosIng) with no concentration restrictions, though manufacturers are expected to minimize impurities like 1,4-dioxane.
- Common uses
- Moisturizers, Cleansers, Lotions, Creams
- Environmental note
- Steareth-15 is synthetic and not biodegradable in all conditions; its production involves ethylene oxide, which has environmental considerations.
Good to know
- Steareth-15 is part of a larger family of steareth emulsifiers (e.g., Steareth-2, Steareth-20) with varying water solubility.
- It is often listed near the middle of an ingredient label, indicating moderate concentration.
Common questions
What is Steareth-15 in beauty products?
Steareth-15 is a man-made ingredient that helps oil and water mix together in your skincare products. Think of it as a peacekeeper that stops your lotion from separating into oily and watery layers. It is made from a fatty alcohol (stearyl alcohol) combined with ethylene oxide, a process that creates a gentle, water-soluble emulsifier. You will find it in many creams, cleansers, and moisturizers where it also helps spread the product evenly on your skin.
What does Steareth-15 do in a beauty product?
In a cosmetic formula, Steareth-15 sits at the boundary between oil and water droplets, reducing surface tension so they can blend into a stable, uniform cream or lotion. It also helps other ingredients spread smoothly and can act as a mild cleansing agent in rinse-off products.
Is Steareth-15 safe for most people?
Steareth-15 is considered safe for cosmetic use at typical concentrations. The main concern is potential contamination with 1,4-dioxane, but industry standards and regulations keep levels very low. It is not a known irritant or sensitizer for most people.
Who should be careful with Steareth-15?
Individuals who strictly avoid synthetic or PEG-based ingredients in their skincare routine
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.