We get a lot of questions about sodium lauryl sulphate and ammonium lauryl sulphate so we've put together some information which will hopefully be useful to people researching the topic.
What makes SLS irritating?
Although sodium lauryl sulphate (SLS) and ammonium lauryl sulphate (ALS) have similar sounding names and are both classed as anionic surfactants, they have very different molecular structures. SLS is a comparatively simple molecule and is therefore quite small in size.
This gives it the ability to penetrate the outer layers of the skin, particularly when used in conditions which encourage the skin's pores to open, such as when in a warm bath or shower.
When SLS penetrates the outer layers of the skin in this way, it comes into contact with more delicate cells that are in the process of being formed in the dermis. It is here that the irritation associated with SLS manifests itself, resulting in reddening and erythema of the skin.
How is ALS different?
ALS, by contrast, is a far more complex molecule and is physically much larger. This means that it is practically impossible for ALS molecules to penetrate the outer layers of the skin and so reach the delicate underlying layers of cells. Due to this difference, ALS is regarded as being considerably less irritating than SLS – on a scale of 0 to 10, where the potential irritancy of water is 0 and that of SLS is 10, ALS scores around 4 – clearly far less irritating than SLS.
Green People only use ALS in those formulations based on organic floral waters. We have found from experience that using other surfactants with floral waters results in formulations that are not stable or effective in use.
SLS and ALS-free shampoos
If you still wish to avoid hair care products containing ALS, then you should choose one of our Daily Aloe, Moisturising, Irritated Scalp or Intensive Repair shampoos, all of which use different surfactants. Full ingredients lists are available on each product page.