Polyethylene glycol
A synthetic polymer used as a coating and binding agent in food supplement tablets and capsules, and as a carrier in tabletop sweetener powders.
What is it?
Polyethylene glycol (PEG) is a synthetic polymer made by joining repeating ethylene oxide units. Different grades are distinguished by molecular weight, with food-grade PEG typically falling in the 300 to 4000 range. It is a waxy or viscous substance at room temperature, water-soluble, and chemically inert under normal food conditions.
What does it do?
In food supplement tablets and capsules, PEG acts as a film-forming plasticiser: it helps bind or coat the tablet, making it easier to swallow and protecting the active ingredient. In tabletop sweetener powders and tablets it serves as a carrier or flow agent, helping the product keep its shape and pour cleanly. It does not provide flavour, colour, or nutrition.
Where you will see it
Almost exclusively in food supplement tablets and capsules, where it forms part of the coating or binding system. It also appears in some tabletop sweetener tablet and powder products as a flow aid. On a UK label it appears as 'polyethylene glycol' or 'E1521'.
What the science says
Exposure is narrow and well below established intake limits
E1521 is only authorised in two narrow food categories, so most people encounter it only through food supplement tablets or tabletop sweetener products, not through everyday food. EFSA's 2018 refined exposure assessment estimated the highest mean daily intake at roughly 3.5mg per kilogram of body weight in children, and the 95th percentile at about 6.1mg/kg bw/day in elderly consumers. Both figures sit within or below the group acceptable daily intake set by earlier scientific committees. EFSA noted the estimates very likely overstate real intake because actual market data showed only around 2% of food supplements on sale contained PEG at all.
Refined dietary exposure estimates for E1521 from food supplement and tabletop sweetener use fall within the range of existing group ADIs, and EFSA concluded the estimates very likely overestimate real exposure given low actual market prevalence.
The Scientific Committee on Food (SCF) established a group ADI of 5mg/kg bw/day for PEG 300-4000; JECFA set a group ADI of 10mg/kg bw/day for PEG 200-10000.
Toxicology: poorly absorbed, largely excreted unchanged
PEG is poorly absorbed from the gut. Higher-molecular-weight grades pass through the digestive tract largely intact and are excreted in faeces; lower-molecular-weight fractions are absorbed to a greater degree but are rapidly cleared by the kidneys. This low bioavailability is central to its use as a laxative medicine at much higher doses than food additive exposure, and is also why food-additive-level intake raises no significant absorption-related concern. No carcinogenicity, genotoxicity, or reproductive toxicity has been established at food-relevant exposure levels in the scientific literature reviewed by EFSA.
Higher-molecular-weight PEG grades (1000 and above) are poorly absorbed from the gastrointestinal tract and excreted primarily in faeces; lower grades show greater but still limited absorption with renal clearance.
Where it stands with the regulators
Who should be careful
People who need to avoid PEG for medical reasons (for example those with a confirmed PEG allergy, which is rare but documented in the context of laxative medicines) should check supplement and sweetener tablets for 'polyethylene glycol' or 'E1521' on the label.
The honest read
E1521 has one of the most restricted uses of any UK-authorised additive: it is only permitted in supplement tablets and capsules, and in tabletop sweetener formats, not in ordinary food. The amounts present in these products are small, and EFSA's review of actual market data found that fewer than one in fifty food supplements on sale contained PEG at all. The relevant scientific committees have reviewed the evidence and set group intake limits; measured exposure from food uses falls well below those limits. PEG is also widely used in pharmaceutical products at far higher doses, which gives regulators a large body of human exposure data. There is no established carcinogenicity, genotoxicity, or endocrine-disruption signal at food-relevant intakes in the reviewed literature.
Related additives
Common questions
Is E1521 banned in the UK?
No. E1521 is authorised in the UK under the assimilated EU Regulation 1333/2008, with its GB status confirmed on 31 December 2020. It is permitted in food supplement tablets and capsules, and in tabletop sweetener powders and tablets.
Is E1521 the same as the laxative PEG?
It is the same substance, but doses are very different. Laxative medicines (such as Movicol) use PEG at grams-per-dose level to draw water into the bowel. As a food additive it appears in supplement tablet coatings at trace amounts, giving exposures measured in milligrams rather than grams.
What foods contain E1521?
Practically only food supplement tablets and capsules (where it forms part of the coating or binding system) and some tabletop sweetener powder and tablet products. It does not appear in mainstream food or drink products.
Is E1521 vegan?
Yes. Polyethylene glycol is a synthetic polymer derived from petrochemical feedstocks and contains no animal-derived ingredients.
Sources
- UK FSA Regulated Products: E1521 Polyethylene Glycol
- Refined exposure assessment of polyethylene glycol (E 1521) from its use as a food additive - EFSA Journal 2018
- Refined exposure assessment of polyethylene glycol (E 1521) - PMC/NCBI
- EU Food Additives Information Portal: Polyethylene Glycol
- UK FSA Approved Additives and E Numbers
See this on every food you scan
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
Get NutraSafe on the App Store