Ingredient review

Ammonium Laureth-9 Sulfate

INCI: AMMONIUM LAURETH-9 SULFATE

A milder relative of SLS that effectively cleanses without stripping the skin as harshly.

beautyskincaresurfactant

In plain English

Ammonium Laureth-9 Sulfate is a cleansing ingredient that helps water mix with oil and dirt so they can be rinsed away. It is a gentler version of sodium lauryl sulfate (SLS) because it has extra ethoxylate groups that make it less irritating to the skin and scalp.

Quick decision guide

Useful, but context matters

Ammonium Laureth-9 Sulfate 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Ammonium Laureth-9 Sulfate.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A synthetic anionic surfactant derived from lauric acid, ethoxylated with 9 moles of ethylene oxide, then sulfated and neutralized with ammonium. It belongs to the alkyl ether sulfate family.

How it works

It reduces the surface tension between water and oil, allowing oils and dirt to be emulsified and washed away. The ethoxylate chain (9 EO) makes it milder than shorter-chain sulfates by reducing protein binding and irritation potential.

Pros

Gentler than SLS

The 9 ethoxylate groups reduce protein binding, making it less irritating to skin and scalp than sodium lauryl sulfate.

Effective foaming

Produces a rich, creamy lather that many users prefer for a satisfying cleansing experience.

Cons and cautions

Potential 1,4-dioxane trace

As an ethoxylated ingredient, it may contain trace amounts of 1,4-dioxane, a possible carcinogen, unless rigorously purified.

Still can be drying

While milder than SLS, it can still strip natural oils if used too frequently or on already dry skin.

Best for

  • People with normal to oily skin or hair
  • Those who want a sulfate cleanser but find SLS too harsh

Use caution if

  • Individuals with severely compromised skin barrier or known sensitivity to ethoxylated ingredients

Usage tips

Use in rinse-off products only; avoid leave-on formulations to minimize irritation risk.
Pair with moisturizing ingredients like glycerin or ceramides to offset any potential dryness.
If you have sensitive skin, patch test a new product containing this surfactant before full use.

Safety summary

Ammonium Laureth-9 Sulfate is considered safe for use in rinse-off cosmetics at typical concentrations. The main safety concern is trace 1,4-dioxane, which is minimized by good manufacturing practices. It is less irritating than SLS and suitable for most skin types.

Research notes

Studies show that increasing ethoxylation reduces skin irritation potential. The Cosmetic Ingredient Review (CIR) panel has reviewed alkyl ether sulfates and found them safe as used. No significant systemic toxicity is expected from topical rinse-off use.

Common label clues

Typical concentration
Typically 5–15% in rinse-off products
Regulatory status
Approved for use in cosmetics in the US (FDA), EU (CosIng), and many other regions. The EU restricts 1,4-dioxane to ≤10 ppm in finished products.
Common uses
Shampoos, Body washes, Facial cleansers, Liquid soaps
Environmental note
Biodegradability is moderate; ethoxylated surfactants can break down in wastewater treatment but may persist in some conditions.

Good to know

  • The number '9' refers to the average ethoxylation level; higher numbers generally mean milder surfactants.
  • Many personal care brands now voluntarily limit 1,4-dioxane levels to below 10 ppm.

Common questions

What is Ammonium Laureth-9 Sulfate in beauty products?

Ammonium Laureth-9 Sulfate is a cleansing ingredient that helps water mix with oil and dirt so they can be rinsed away. It is a gentler version of sodium lauryl sulfate (SLS) because it has extra ethoxylate groups that make it less irritating to the skin and scalp.

What does Ammonium Laureth-9 Sulfate do in a beauty product?

It reduces the surface tension between water and oil, allowing oils and dirt to be emulsified and washed away. The ethoxylate chain (9 EO) makes it milder than shorter-chain sulfates by reducing protein binding and irritation potential.

Is Ammonium Laureth-9 Sulfate safe for most people?

Ammonium Laureth-9 Sulfate is considered safe for use in rinse-off cosmetics at typical concentrations. The main safety concern is trace 1,4-dioxane, which is minimized by good manufacturing practices. It is less irritating than SLS and suitable for most skin types.

Who should be careful with Ammonium Laureth-9 Sulfate?

Individuals with severely compromised skin barrier or known sensitivity to ethoxylated ingredients

Research sources

Cosmetic Ingredient Review (CIR) – Safety Assessment of Alkyl Ether SulfatesOpenPubChem – Ammonium Laureth-9 SulfateOpenEuropean Chemicals Agency (ECHA) – 1,4-Dioxane InformationOpen

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.