Encyclopedia · surfactant
Ammonium laureth sulfate
The ammonium-salt version of SLES, an ethoxylated sulfate cleanser that is gentler than lauryl sulfates and can carry a trace by-product called 1,4-dioxane.
What it is
Ammonium laureth sulfate (ALES) is ethoxylated, sulfated lauryl alcohol neutralized with ammonia. The Cosmetic Ingredient Review assessed it together with SLES, most recently in an amended 2010 report on salts of sulfated ethoxylated alcohols (Robinson 2010). Dermatology reviews list the laureth sulfates (sodium, ammonium, triethanolamine) as good cleansers with good foam that suit normal-to-dry hair better than the lauryl sulfates (D'Souza 2015).
How it works
It cleans by the anionic mechanism described for sodium laureth sulfate. Ethoxylation adds mildness compared with lauryl sulfates (Thompson 2023). See how shampoo works.
What the studies show
- Sodium and ammonium laureth sulfate caused no adverse responses in toxicology testing apart from irritation. They are safe when formulated to be non-irritating (Robinson 2010).
- A dermatology review describes laureth sulfates as good cleansing and foam agents suited to normal-to-dry hair (D'Souza 2015).
- US FDA notes ingredients with "-eth-" may carry the ethoxylation by-product 1,4-dioxane, and that levels have fallen over decades (FDA).
How it's used in studies
We found no clinical hair studies specific to ALES. It is used as a primary surfactant in the same way as SLES.
Side effects and safety
- Irritation potential is similar to SLES, and the CIR did not find it to be a sensitizer (Robinson 2010).
- 1,4-dioxane is a possible trace contaminant, as for SLES. New York State caps personal care products, including shampoo, at 1 ppm from the end of 2023.
- It is a permitted cosmetic ingredient in the US, EU and UK.
Bottom line
Choose or avoid ALES on the same basis as SLES: an effective, moderately gentle cleanser for most scalps, less ideal for very sensitive scalps or dry, coily or freshly coloured hair. No ALES-specific hair data exist.
Studies 4
Robinson VC et al. Final report of the amended safety assessment of sodium laureth sulfate and related salts of sulfated ethoxylated alcohols. Int J Toxicol. 2010
Result: Sodium and ammonium laureth sulfate caused no adverse responses in toxicology testing other than irritation; dermal and eye irritants but not sensitizers; safe when formulated to be non-irritating.
Read the study ↗D'Souza P, Rathi SK. Shampoo and Conditioners: What a Dermatologist Should Know? Indian J Dermatol. 2015
Result: Dermatology review of shampoo and conditioner ingredients: foam does not equal cleaning, non-ionics are the mildest and weakest cleansers, and saponin-based natural cleansers lather but clean poorly.
Read the study ↗US Food and Drug Administration. 1,4-Dioxane in Cosmetics: A Manufacturing Byproduct. Content current as of 2022-03-03
Result: Average 1,4-dioxane in surveyed cosmetics fell from 50 ppm (1981) to 19 ppm (1997); in 2008 about 80% of products had none detected (limit 1 ppm), maximum 11.6 ppm. Ingredients with -eth-, PEG or polyoxyethylene in the name can carry it; FDA has set no federal limit.
Read the study ↗Thompson CJ, Ainger N, Starck P, Mykhaylyk OO, Ryan AJ. Shampoo Science: A Review of the Physiochemical Processes behind the Function of a Shampoo. Macromol Chem Phys. 2023
Result: Reviews how surfactants lift soil from hair (roll-up, emulsification, solubilization), why shampoos pair a primary anionic with an amphoteric co-surfactant, and states that foaming does not affect cleaning. Two authors were from Unilever R&D.
Read the study ↗Related
- Sodium laureth sulfateThe workhorse cleanser of mainstream shampoos, SLS with a short ethylene-oxide chain added, which keeps most of the cleaning and foam and is gentler, with a trace by-product called 1,4-dioxane.
- Ammonium lauryl sulfateThe ammonium-salt twin of SLS, a strong cleanser with essentially the same cleaning power and irritation profile.
- Sodium lauryl sulfateA cheap, strong cleanser and foamer that removes oil very well but is the most irritating common shampoo surfactant, so dermatologists use it as their standard test irritant.
- Cocamidopropyl betaineThe most common helper surfactant in shampoo, which makes sulfate cleansers gentler, thicker and foamier, and a rare cause of scalp allergy that usually comes from manufacturing impurities.
- How shampoo worksShampoo is water plus a blend of cleansing molecules that lift oil off your scalp and hair, and the blend matters far more than any single label word.