Ingredient review
Nonyl Nonoxynol-100
INCI: Nonyl Nonoxynol-100
A synthetic emulsifier that helps mix oil and water, but may be drying or irritating for sensitive skin.
In plain English
Nonyl Nonoxynol-100 is a man-made ingredient that helps oil and water blend together in products like cleansers and shampoos. It works by reducing surface tension, which allows the product to spread easily and rinse away dirt and oil. While effective, it can be a bit harsh for very sensitive or dry skin because it can strip natural oils.
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-100 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-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
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 nonionic surfactant and emulsifier derived from ethylene oxide and nonylphenol. It is part of the alkylphenol ethoxylate family, commonly used in industrial and personal care products for its ability to lower surface tension.
How it works
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers and shampoos lift dirt, oil, and makeup from the skin and hair so they can be rinsed away easily.
Pros
Strong cleanser
Effectively removes excess oil, dirt, and makeup, making it useful in deep-cleansing formulas.
Good emulsifier
Helps create smooth, stable mixtures of oil and water, improving product feel and performance.
Cons and cautions
Potential irritation
Can strip the skin's natural oils, leading to dryness or irritation, especially for sensitive skin types.
Environmental concerns
Related alkylphenol ethoxylates have raised environmental persistence questions, though this specific variant is less studied.
Best for
- People with normal to oily skin looking for effective cleansing
- Those using rinse-off products like shampoos and body washes
Use caution if
- Individuals with very dry, sensitive, or compromised skin barriers
- Those seeking purely natural or biodegradable 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 sensitive skin, and environmental concerns exist for the broader chemical class.
Research notes
Limited direct studies on Nonyl Nonoxynol-100 in cosmetics. Broader research on alkylphenol ethoxylates indicates potential for skin irritation and environmental persistence, but longer-chain variants may be less concerning.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US and EU within concentration limits. Some related alkylphenol ethoxylates are restricted in the EU due to environmental concerns.
- Common uses
- Cleansers, Shampoos, Body washes, Emulsions
- Environmental note
- Nonylphenol ethoxylates have been scrutinized for potential environmental persistence and aquatic toxicity. Nonyl Nonoxynol-100 is a longer-chain variant, which may have different properties, but caution is warranted.
Good to know
- This ingredient is often found in industrial cleaners as well as personal care, so check the product type.
- It is not typically used in high concentrations in leave-on skincare.
Common questions
What is Nonyl Nonoxynol-100 in beauty products?
Nonyl Nonoxynol-100 is a man-made ingredient that helps oil and water blend together in products like cleansers and shampoos. It works by reducing surface tension, which allows the product to spread easily and rinse away dirt and oil. While effective, it can be a bit harsh for very sensitive or dry skin because it can strip natural oils.
What does Nonyl Nonoxynol-100 do in a beauty product?
It reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. This helps cleansers and shampoos lift dirt, oil, and makeup from the skin and hair so they can be rinsed away easily.
Is Nonyl Nonoxynol-100 safe for most people?
Generally considered safe for use in rinse-off cosmetics at typical concentrations. However, it can be drying or irritating for sensitive skin, and environmental concerns exist for the broader chemical class.
Who should be careful with Nonyl Nonoxynol-100?
Individuals with very dry, sensitive, or compromised skin barriers Those seeking purely natural or biodegradable 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.