What is Ammonium Lauryl Sulphate?

What is Ammonium Lauryl Sulphate?

Ammonium lauryl sulphate, also known as ALS is a commonly used fat based molecule. It is usually made from coconut or palm kernel oil. The fat molecules in the oil are broken down and then reacted to produce something called a ‘surfactant’ – a compound that is often used in detergents, emulsifiers (stabiliser), foaming agent and dispersant.

It is often  found in hygiene products like cleansers, shampoos and soaps and is popular due to it wide variety of uses and its relatively cheap cost.

While related, ammonium lauryl sulphate is not the same as ammonium laureth sulphate (ALES) which works in a similar manner but has additional ‘ether’ groups in the fatty end of the molecule.


How does it work?

The key part of this molecule is the ‘lauryl sulphate’ section. The lauryl sulphate part has one fatty end and one charged end which lets it work as an adapter between oil and water which would otherwise repel each other and refuse to mix. In the same way that washing up liquid can help water wash grease off a frying pan, detergents in cleansers and soaps can remove make up and oily debris on the face by grabbing it with their fatty end and then getting pulled away by water grabbing their charged end.

In both shampoos and toothpaste, ALS can be responsible for the foaming and lather produced during use as it forms a thin film that traps air into bubbles.



The most common side effect when using products containing ammonium lauryl sulphate is skin irritation. In the same way that the detergent pulls oily debris off your skin, it can also pull of the skin’s necessary oils and upset the barrier they provide. This can lead to dry, flaky and irritated skin as water can escape faster without the oil layer intact. Skin irritation caused by them can be worse in people with certain skin conditions like eczema.


Interactions with other medicines:

ALS is not thought to interact with any medicines.


Other names

Monododecyl ester ammonium salt, Ammonium dodecyl sulfate, Ammonium lauryl sulfate