Polysorbate 20
A synthetic emulsifier made from sorbitol and lauric acid, used to stop fat and water separating in processed foods.
Lab studies show polysorbate 20 disrupts the gut's protective lining at concentrations below what current regulations permit, and may trigger a low-grade inflammatory response in the gut. Research into long-term effects on gut health is ongoing.
What is it?
Polysorbate 20, also called polyoxyethylene (20) sorbitan monolaurate, is a synthetic surfactant. It is made by reacting sorbitol with lauric acid (a fatty acid from coconut or palm kernel oil) and then adding ethylene oxide. The '20' refers to the number of ethylene oxide units attached. It is in the same polysorbate family as E433 (polysorbate 80), which has a longer fatty acid chain.
What does it do?
It acts as an emulsifier by having both water-attracting and fat-attracting parts in one molecule. This lets it sit at the boundary between oil and water droplets, preventing them from separating. It is also a mild solubiliser, helping oil-soluble flavours and colours disperse evenly into water-based products. Its surface-active (surfactant) properties allow it to interact with cell membranes, which is central to the gut-lining concern.
Where you will see it
Found in ice cream, whipped cream products, flavoured milk drinks, chewing gum, confectionery coatings, bakery glazes, liquid dietary supplements, and some canned and bottled sauces. Also used in pharmaceutical tablet coatings and cosmetics (where it is not food-regulated). On UK labels it appears as 'polysorbate 20', 'E432', or 'polyoxyethylene (20) sorbitan monolaurate'.
What the science says
Gut barrier disruption at low concentrations
A 2023 laboratory study tested polysorbate 20 and polysorbate 80 directly on human gut epithelial cells. It found that both emulsifiers damaged the gut lining and triggered a pro-inflammatory response at concentrations 20 times lower than the amounts currently permitted in food. The disruption involved direct cell toxicity at higher doses and an inflammatory signalling response at lower doses. These are laboratory measurements, not human trial outcomes, so whether the same concentrations reach the gut lining intact in real eating patterns is not established.
Polysorbate 20 impaired gut epithelial barrier integrity and caused proinflammatory signalling at concentrations 20 times lower than current authorised food-use levels in laboratory cell models.
Effects on gut microbiome composition
Several studies have looked at whether dietary emulsifiers alter the balance of bacteria in the gut. Research on polysorbates and related emulsifiers has found shifts in microbial community composition and reductions in short-chain fatty acids, which gut bacteria produce and which help maintain the gut lining. Most of the strongest data applies to polysorbate 80 (E433), which is more widely studied; evidence specific to polysorbate 20 is more limited. A placebo-controlled randomised trial published in 2025 found that emulsifier intake affected microbial composition, with effects on short-chain fatty acid concentrations.
Dietary emulsifiers including polysorbates alter gut microbiota composition and reduce concentrations of short-chain fatty acids in human and in vitro models.
A randomised placebo-controlled trial found emulsifier supplementation affected microbial composition, with lower short-chain fatty acid concentrations in some emulsifier groups.
1,4-dioxane contamination risk in manufacture
The ethoxylation process used to make polysorbate 20 can leave trace amounts of 1,4-dioxane as a manufacturing by-product. 1,4-dioxane is classified as a possible human carcinogen (IARC Group 2B, Vol. 71, 1999), based on sufficient evidence in animals and inadequate evidence in humans; this classification has not been updated as of 2026. Regulatory limits for residual 1,4-dioxane in food-grade polysorbates are set under EU and UK law, and manufacturers are required to purify the final product to keep levels within those limits. The concern is about manufacturing quality control rather than polysorbate 20 itself.
1,4-dioxane, classified by IARC as a possible human carcinogen (Group 2B, IARC Monographs Vol. 71, 1999), can remain as a trace contaminant in polysorbates following the ethoxylation manufacturing step. The Group 2B classification remains current as of 2026.
Where it stands with the regulators
Who should be careful
People with inflammatory bowel conditions (Crohn's disease, ulcerative colitis) may want to monitor their intake of polysorbate emulsifiers given the gut-lining research, though human clinical evidence is limited. Anyone with a known sensitivity to polyethylene glycol (PEG) compounds or polysorbates should check labels for 'E432' or 'polysorbate 20'. There is no specific allergen declaration requirement under UK food law for polysorbate 20, so checking the ingredient list directly is the only way to identify it.
The honest read
Polysorbate 20 sits in a group of emulsifiers that have attracted genuine scientific scrutiny since around 2015, when animal studies linked related emulsifiers to gut inflammation and metabolic changes. The 2023 Ogulur study is the most direct evidence for polysorbate 20 specifically, showing gut lining disruption at concentrations lower than regulators currently permit, but that study used cell cultures, not people. Human randomised trials of emulsifier exposure are beginning to appear and show microbiome effects, though the clinical significance, meaning whether this translates to measurable disease risk in typical diets, is not yet established. The honest position is that the cell-level signal is real and consistent across multiple labs, the human evidence is still thin, and regulators have not yet acted on the 2023 data. This science is live.
Related additives
Common questions
Is E432 banned in the UK?
No. E432 is authorised for use in the UK under the retained EU additives framework and the UK FSA approved-additives list. It is also permitted across the EU under Regulation 1333/2008.
Is there real concern about polysorbate 20, or is it just internet noise?
There is a genuine scientific signal. A 2023 peer-reviewed study in the journal Allergy found polysorbate 20 damages the gut lining's protective barrier at concentrations below the levels permitted in food, in cell models. This is not the same as proof of harm in people eating normal diets, but it is not internet noise either. Research is ongoing and regulators have not yet updated their position in response to these findings.
What foods contain E432?
Ice cream, whipped cream, confectionery coatings, flavoured milk drinks, bakery glazes, some sauces, chewing gum, and liquid dietary supplements are the most common sources. It also appears in pharmaceutical tablet coatings and cosmetics, though those are not food-regulated. Look for 'polysorbate 20' or 'E432' in the ingredients list.
Is E432 vegan?
Polysorbate 20 is derived from sorbitol and lauric acid (typically from coconut or palm kernel oil), not from animal sources, so it is generally considered vegan. However, some strict vegans object to it because the manufacturing process uses ethylene oxide, and the palm kernel oil supply chain raises separate ethical concerns around land use. It is not an animal product under standard vegan definitions.
Sources
- UK FSA Regulated Products Register: E432 Polysorbate 20
- UK Food Standards Agency: Approved additives and E numbers
- Ogulur et al. (2023) - Mechanisms of gut epithelial barrier impairment caused by food emulsifiers polysorbate 20 and polysorbate 80, Allergy (Wiley)
- Effect of five dietary emulsifiers on inflammation, permeability, and the gut microbiome: a placebo-controlled randomized trial (2025), ScienceDirect
- Direct impact of commonly used dietary emulsifiers on human gut microbiota, PubMed Central
- IARC Monographs Volume 71 (1999): 1,4-Dioxane evaluation (Group 2B) - INCHEM/IARC
- Agents Classified by the IARC Monographs, Volumes 1-141 (confirms 1,4-dioxane Group 2B current)
- EU Regulation (EC) No 1333/2008 on food additives (Annex II, polysorbates E432-E436)
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