Linear Alkylbenzene Sulphonate (LAS)
Linear alkylbenzene sulphonate (LAS) is one of the most widely used synthetic detergent ingredients in the world; it is the main component in laundry and washing-up detergents that removes dirt and grease. In concentrated form it is a serious eye irritant, but in products it is present in diluted form. Unlike the older branched types, it biodegrades readily in the presence of oxygen.
Risk range
1 is the lowest and 10 the highest risk. The range depends on the amount used, whether the product is rinsed off and how it is used. The Temiz İçerik app uses the same ranges.
Hand washing-up and surface products are at the lower end because of brief contact; concentrated powder detergents and uses with a high risk of splashes in the eyes are at the upper end.
What is LAS and what is it used for?
LAS is an anionic surfactant made by sulphonating petroleum-derived straight-chain alkylbenzene and then neutralising it. One end of the molecule likes oil and the other likes water; this lets it wrap around greasy dirt on fabric or dishes so it can be washed away with water.
Because it is cheap, effective and works well in both hot and cold water, it has been the cornerstone of detergent formulas for decades. On labels it is often listed only under the heading “anionic surfactants”, together with a percentage range.
Which products contain it?
- Powder and liquid laundry detergents
- Hand washing-up liquids
- Multi-purpose surface and floor cleaners
- Industrial cleaning products
Under EU detergent legislation, ingredients on detergent labels are grouped by percentage range (for example “5–15% anionic surfactants”). LAS is usually the largest part of this group.
Is it harmful? The scientific assessment
Under the EU CLP classification, pure or concentrated LAS is labelled as harmful if swallowed (H302), causing skin irritation (H315) and causing serious eye damage (H318). These classifications are for the raw material; because LAS is diluted in household products, the finished product often carries only an eye irritation warning.
As for the skin, LAS can dissolve the skin's natural oils and cause dryness and irritation; washing up without gloves for long periods can contribute to the dry, cracked skin known as “dishpan hands”. LAS has no classification as a carcinogen or endocrine disruptor.
Environmentally, LAS replaced the branched alkylbenzene sulphonates that broke down poorly and caused foaming problems in rivers in the 1960s. Thanks to its straight-chain structure, it breaks down quickly in treatment plants and in the presence of oxygen. Although it is harmful to aquatic life in concentrated form, its levels in treated waste water are much lower.
Who should be careful?
- People with eczema or sensitive hands: Wearing gloves when washing up largely prevents irritation.
- Homes with children: Concentrated liquid detergents and pods cause serious irritation if they get into the eyes; keep them out of children's reach.
- If it gets into the eyes: Rinse with plenty of water for at least 15 minutes; if symptoms persist, get medical help. If swallowed, call your local poison control centre (in Türkiye: UZEM, 114).
What to do when you see it on a label
Used correctly, LAS is not an ingredient that calls for concern. Using detergent at the recommended dose protects both your skin and the environment; more detergent does not mean cleaner laundry, only more rinsing. For sensitive skin, rinsing laundry well is important. If you are looking for a plant-derived alternative, products made with milder surfactants such as coco-glucoside may be preferable; SLS, a similar anionic cleanser, is also used together with LAS in many products.
Frequently asked questions
Is LAS harmful to the skin?
Brief contact in diluted form causes no problems for most people; prolonged and frequent contact can dry and irritate the skin. Wearing gloves is the simplest precaution.
Does LAS break down in nature?
Yes. Thanks to its straight-chain structure, it biodegrades readily in the presence of oxygen and in treatment plants. This is largely why the foaming problem of the older branched types has been solved.
What does “anionic surfactant” on the label mean?
These are negatively charged cleaning agents that dissolve dirt. In detergents, LAS usually makes up most of this group.
Sources
Updated: 2026-10-11 · How we score
This page is for general information and is not personal medical advice. Warnings on the product label and the advice of a health professional always come first.