Sodium laurylsulphate
A surfactant and foaming agent derived from lauryl alcohol. Not permitted as a food additive in the UK or EU.
Not currently permitted in UK or EU food. In laboratory studies, it disrupts the gut lining by opening tight junctions between intestinal cells, even at low concentrations.
What is it?
Sodium laurylsulphate (also called sodium dodecyl sulphate, SDS or SLS) is a synthetic anionic surfactant made from lauryl alcohol, itself derived from coconut or palm kernel oil, reacted with sulphur trioxide and neutralised with sodium hydroxide. It reduces surface tension between water and oils and is a powerful foaming agent.
What does it do?
As a surfactant, it lowers surface tension, allowing oil and water to mix. In food applications it acts as an emulsifier, whipping aid and foam stabiliser. It disrupts lipid membranes and solubilises proteins, which is why it is widely used in biochemistry laboratories to denature proteins for gel electrophoresis (SDS-PAGE). These same membrane-disrupting properties are responsible for its effects on biological tissues.
Where you will see it
E487 is not a permitted food additive in the UK or EU, so it should not appear in the ingredients list of any food sold under UK or EU law. In the United States, the FDA permits it in a narrow set of uses including certain dried egg products, marshmallow products, and dry beverage bases at tightly controlled levels. Outside food, it is widely used in toothpaste, shampoo, soap, and pharmaceutical tablet coatings. On a UK food label it would appear as 'E487' or 'sodium laurylsulphate'.
What the science says
Gut lining disruption in lab studies
Laboratory studies using human intestinal cell models (Caco-2 monolayers) show that SLS disrupts the tight junctions between cells at concentrations far below those that kill the cells outright. This increases the permeability of the gut lining, allowing molecules to pass through that would normally be kept out. Barrier function recovered after SLS was removed in these cell models. These are laboratory findings, not studies of people eating food containing SLS.
SLS caused concentration-dependent loss of intestinal barrier integrity in Caco-2 cell monolayers, increasing mannitol permeability at concentrations as low as 64-80 micrograms/mL without causing outright cell death, indicating tight junction disruption precedes cytotoxicity.
SLS reversibly opens cellular tight junctions and increases mucosal permeability; barrier integrity recovered when SLS was removed from cell cultures.
Oral mucosal irritation
SLS is the best-documented cause of recurrent aphthous ulcers (mouth ulcers) linked to toothpaste. Controlled trials found that SLS-free toothpaste significantly reduced the number of mouth ulcers in susceptible individuals. This is a direct mucosal irritant effect at the concentrations used in personal care products, not a food-dose effect.
SLS-free toothpaste significantly reduced aphthous ulcer frequency compared to SLS-containing toothpaste in randomised controlled trials of susceptible individuals.
A literature review found consistent evidence that SLS in toothpaste is associated with oral mucosal irritation and that epithelial desquamation is the proposed mechanism.
Regulatory non-authorisation in the UK and EU
Neither the UK Food Standards Agency nor the EU's Regulation 1333/2008 on food additives includes E487 on the list of permitted food additives. The E number exists in reference databases but the substance has no authorised food use in the UK or EU. Using it in food would be unlawful without a specific authorisation.
E487 does not appear on the UK FSA's approved additives and E numbers list.
Sodium lauryl sulfate is listed under 21 CFR 172.822 as a permitted direct food additive in the United States for limited uses including dried egg products, marshmallows and dry beverage bases, with maximum levels specified per category.
Where it stands with the regulators
Who should be careful
Because E487 is not permitted in UK or EU food, it should not be present in any UK food product. Anyone encountering 'E487' or 'sodium laurylsulphate' on a UK food label should treat this as a labelling anomaly and query it with the manufacturer or the FSA. People with a known sensitivity to SLS (for example, those who develop mouth ulcers from SLS-containing toothpaste) may wish to check ingredient lists on imported or non-EU products.
The honest read
The E number exists in databases, but this additive has no legal food use in the UK or EU. The concern is primarily regulatory: its absence from the permitted list means it should not be in UK food at all. The underlying science from laboratory studies raises questions about gut lining integrity at high concentrations, but these are cell-culture findings, not studies of dietary intake at food-relevant doses. The mucosal irritation link from toothpaste studies is the most robustly evidenced effect and involves concentrations far higher than any hypothetical food exposure. The gap between laboratory findings and real-world food risk is wide, but the regulatory position is clear: not authorised, not permitted.
Related additives
Common questions
Is E487 banned in the UK?
It is not listed as a permitted food additive on the UK FSA's approved additives list or under EU Regulation 1333/2008 (which the UK retained after Brexit). Without an authorisation, it cannot lawfully be used as a food additive in the UK. It is permitted in limited food applications in the United States.
Can E487 damage the gut lining?
Laboratory studies using human intestinal cell models show SLS can disrupt tight junctions between gut cells at low concentrations, increasing permeability. These findings come from cell cultures, not from studies of people eating foods containing SLS. The relevance to dietary exposure is uncertain. Because it is not a permitted UK food additive, the question of dietary gut exposure in the UK does not practically arise.
What foods contain E487?
No UK or EU food should legally contain E487. In the United States, it is permitted in a limited range of products including some dried egg products, marshmallows and dry beverage bases. It is more commonly found in toothpaste, shampoo, soap and pharmaceutical tablet coatings.
Is E487 vegan?
Sodium laurylsulphate is synthesised from lauryl alcohol, which is typically derived from coconut or palm kernel oil. The synthesis route is plant-derived, so it is generally considered vegan. However, the palm kernel oil origin raises separate sustainability concerns.
Sources
- UK FSA: Approved additives and E numbers
- US FDA eCFR 21 CFR 172.822: Sodium lauryl sulfate
- The Effect of Excipients on the Permeability of BCS Class III Compounds and Implications for Biowaivers (PubMed PMID 26286187)
- The Yin and Yang of Sodium Lauryl Sulfate Use for Oral and Periodontal Health: A Literature Review (PMC10506142)
- Healy CM et al. — Effect of low-dose aspirin and SLS-free toothpaste on recurrent aphthous ulcers, Journal of Oral Pathology and Medicine
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