Ingredient review
Nonyl Nonoxynol-11 Phosphate
INCI: Nonyl Nonoxynol-11 Phosphate
A synthetic emulsifier that helps mix oil and water, but may be drying or irritating for sensitive skin.
In plain English
Nonyl Nonoxynol-11 Phosphate is a man-made ingredient that helps oil and water blend together in products like cleansers and shampoos. It works by reducing surface tension, allowing the product to spread easily and rinse off cleanly. Because it's a surfactant, it can strip natural oils from the skin, which might leave some people feeling dry or irritated.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Nonyl Nonoxynol-11 Phosphate can be useful, but watch for some irritation potential.
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 Nonyl Nonoxynol-11 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
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
A synthetic phosphate ester surfactant derived from nonoxynol, a type of nonionic surfactant. It is commonly used as an emulsifier and cleansing agent in personal care products.
How it works
It lowers the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers remove dirt, oil, and makeup from the skin and hair, and helps rinse them away with water.
Pros
Effective cleanser
Removes excess oil, dirt, and makeup efficiently, making it useful for oily skin types.
Stable emulsions
Helps keep oil and water mixed, so products maintain a consistent texture and don't separate.
Cons and cautions
Potential dryness
As a surfactant, it can strip the skin's natural oils, leading to tightness or flakiness, especially for dry skin.
Irritation risk
May cause stinging or redness in sensitive skin, particularly in high concentrations or leave-on products.
Best for
- People with oily or combination skin
- Those using rinse-off products like cleansers and shampoos
Use caution if
- People with very dry or sensitive skin
- Those seeking entirely natural or plant-based ingredients
Usage tips
Safety summary
Generally considered safe for use in rinse-off cosmetics at typical concentrations. However, it can be drying or irritating for some individuals, especially those with sensitive or compromised skin. Avoid contact with eyes.
Research notes
Limited peer-reviewed studies specifically on Nonyl Nonoxynol-11 Phosphate in cosmetics. Related nonoxynol surfactants have been studied for skin irritation and environmental persistence. The Cosmetic Ingredient Review (CIR) has evaluated similar nonoxynol compounds and found them safe for rinse-off use at low concentrations.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US and EU within regulated concentration limits. Not classified as a restricted ingredient by the FDA or EU CosIng database.
- Common uses
- Cleansers, Shampoos, Body washes, Emulsions
- Environmental note
- Nonoxynol derivatives can be slow to biodegrade and may have aquatic toxicity concerns. However, rinse-off use reduces environmental impact compared to industrial applications.
Good to know
- Nonyl Nonoxynol-11 Phosphate is part of the nonoxynol family, which includes ingredients sometimes used in industrial applications, but cosmetic-grade versions are purified for safety.
- It is not a common ingredient in modern 'gentle' or 'natural' skincare lines.
Common questions
What is Nonyl Nonoxynol-11 Phosphate in beauty products?
Nonyl Nonoxynol-11 Phosphate is a man-made ingredient that helps oil and water blend together in products like cleansers and shampoos. It works by reducing surface tension, allowing the product to spread easily and rinse off cleanly. Because it's a surfactant, it can strip natural oils from the skin, which might leave some people feeling dry or irritated.
What does Nonyl Nonoxynol-11 Phosphate do in a beauty product?
It lowers the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers remove dirt, oil, and makeup from the skin and hair, and helps rinse them away with water.
Is Nonyl Nonoxynol-11 Phosphate safe for most people?
Generally considered safe for use in rinse-off cosmetics at typical concentrations. However, it can be drying or irritating for some individuals, especially those with sensitive or compromised skin. Avoid contact with eyes.
Who should be careful with Nonyl Nonoxynol-11 Phosphate?
People with very dry or sensitive skin Those seeking entirely natural or plant-based 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.