E-numbers / Preservatives / E218
also: Methyl para-hydroxybenzoate · Methyl paraben · Methyl p-hydroxybenzoate
A synthetic preservative from the paraben family, added to stop mould, yeast and bacteria growing in certain processed foods.
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Methylparaben weakly mimics oestrogen and is classed as an endocrine-disrupting chemical.
1
of the 43,325 UK supermarket foods we checked declare E218 in their ingredients
That is under 0.1%, counted by its code or its name.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. Methylparaben weakly mimics oestrogen and is classed as an endocrine-disrupting chemical. Prenatal exposure has been linked to altered thyroid hormones in mothers, lower birthweight, preterm birth, and doubled odds of an ADHD diagnosis in children. Animal and lab studies show it can stimulate breast tumour growth and disrupt the thyroid system.
Methylparaben (methyl p-hydroxybenzoate) is the methyl ester of para-hydroxybenzoic acid. It is manufactured synthetically from p-hydroxybenzoic acid and methanol, yielding a white crystalline powder. Para-hydroxybenzoic acid occurs naturally in some plants, but the food-grade compound is industrially synthesised.
Methylparaben disrupts the cell membranes of bacteria, moulds and yeasts, preventing them from reproducing. It works across a wide pH range, which makes it practical in acidic foods such as pate jelly coatings and sweet confectionery. It is often used alongside other parabens or preservatives to extend its antimicrobial range.
UK-permitted food uses are narrow: jelly coatings on meat products such as pate (up to 1g/kg), non-chocolate confectionery (up to 300mg/kg), dried-meat product surface treatments, and liquid dietary food supplements (up to 2g/kg). On a UK ingredient label it appears as E218 or as methyl p-hydroxybenzoate.
Methylparaben binds to and activates oestrogen receptors, though far more weakly than natural oestrogen. Animal studies confirm this is mediated through the oestrogen receptor: blocking the receptor with drugs removes the effect. In rats, doses close to the regulator-set acceptable daily intake produced measurable increases in uterine weight and activated oestrogen-responsive genes.
Methylparaben and ethylparaben produced significant uterine-weight increases in immature female rats at doses close to the regulator-set acceptable daily intake, with oestrogen-responsive gene upregulation confirmed to be receptor-mediated.
Parabens show weak oestrogen-like activity in laboratory and animal tests and are classed as endocrine-disrupting chemicals with both oestrogenic and antiandrogenic potential.
Methylparaben has been found to alter the structure and function of the thyroid gland in animal experiments, including at doses described by researchers as within the range considered safe by current regulation. The changes include reduced follicular tissue area and disrupted expression of genes controlling thyroid hormone production. In a prospective Canadian pregnancy cohort, higher methylparaben detected in meconium was linked to decreased maternal thyroid hormones and raised hypothyroxinemia risk.
Subacute methylparaben exposure in male rats produced significant thyroid structural changes (reduced follicular and colloid area) and disrupted gene expression for hormone biosynthesis, with the authors noting effects at doses within currently legislated limits.
Prenatal methylparaben detected in meconium was associated with decreased maternal TSH (24%), reduced total T3 (16%), and a 2.5-fold increase in hypothyroxinemia risk in a prospective cohort of 394 pregnancies.
Two prospective cohort studies have found associations between higher prenatal methylparaben exposure and adverse child outcomes. One study of 345 Canadian mother-child pairs found prenatal exposure more than doubled the odds of an ADHD diagnosis at age 6-7. A separate study found associations between gestational paraben exposure and increased externalising behaviour in toddlers at ages 2-4. These are observational studies, so they identify associations, not proven causes.
Prenatal methylparaben detected in meconium was associated with more than doubled odds of ADHD at ages 6-7 (OR 2.33, 95% CI 1.45-3.76), as well as nearly fivefold increased preterm birth risk and reduced birthweight in 345 Canadian children.
In individual paraben analyses of a prospective pregnancy cohort, gestational methyl, ethyl and propyl paraben exposure was associated with increased externalising behaviours in children at ages 2, 3, and 4 years, assessed by the Child Behavior Checklist.
Laboratory and animal studies show methylparaben can stimulate the growth of oestrogen-receptor-positive breast tumours. A 2016 study found that exposure to methylparaben at physiological doses increased tumour size in mouse models, and enhanced the activity of cancer stem-cell markers. A 2023 study found increased tumour volume and pulmonary metastases in paraben-exposed mice. These are animal and lab findings; no human trial has directly tested this relationship.
Methylparaben at physiological levels stimulated tumour-initiating cell activity in oestrogen-receptor-positive breast cancer models via stem-cell markers (NANOG, OCT4), partially independent of the classical oestrogen receptor pathway.
Chronic paraben exposure at doses within the FDA acceptable daily intake increased mammary tumour volume and produced a 28-91% increase in pulmonary metastases in mouse models.
EFSA's AFC Panel set a group acceptable daily intake of 0-10mg per kilogram of body weight per day for methyl and ethyl parabens in 2004, confirmed at the same level in subsequent reviews. This ADI was retained despite emerging evidence, because dietary exposure from food use was judged to be well below the limit. Researchers have since challenged whether this ADI adequately accounts for combined food-plus-cosmetics exposure and effects at low doses. RIVM (the Dutch equivalent of Public Health England) concluded in 2017 that the endocrine-disrupting potential of methylparaben in humans remains unclear.
EFSA's AFC Panel set a group ADI of 0-10mg/kg body weight per day for methylparaben and ethylparaben, excluding propylparaben due to reproductive concerns; this followed a 1994 temporary ADI at the same level.
RIVM concluded that whether methyl-, ethyl- and propylparaben disrupt hormones in animals or humans cannot be determined from available data, and that aggregate exposure from multiple products is a residual concern.
People who are pregnant or planning pregnancy may wish to limit unnecessary exposure given the observational evidence linking prenatal paraben levels to altered thyroid hormones, preterm birth and ADHD risk in children. Anyone with a known paraben contact allergy (rare but documented) should check labels for E218 or methyl p-hydroxybenzoate. The permitted food categories are narrow, so avoidance in everyday shopping is straightforward: check the ingredients list on pate, jelly-coated processed meats, non-chocolate confectionery and liquid supplements.
Methylparaben has been in food use for decades and its dietary exposure from permitted categories is low compared with the regulator-set ADI. However, that ADI was designed around food intake alone; most people also absorb parabens daily through cosmetics, toiletries and pharmaceuticals, and regulators have not formally set a combined-route ceiling. Independent assessors including RIVM have said the endocrine-disrupting potential of methylparaben in humans remains genuinely unclear. Newer animal studies have found thyroid and breast-tumour effects at doses within or close to current approved limits. Prospective human cohort data have linked prenatal exposure to ADHD and child behaviour signals, though these are observational associations and cannot confirm cause. The science is active, not settled.
No. E218 is approved for use in the UK under the FSA authorised additives list and retained EU Regulation 1333/2008. It is permitted in a small number of specific food categories: jelly coatings on meat products such as pate, non-chocolate confectionery, dried-meat surface treatments, and liquid dietary food supplements.
Laboratory and animal studies show methylparaben binds oestrogen receptors and can alter thyroid function. A Dutch national health review in 2017 concluded the evidence in humans is still unclear. Observational pregnancy studies have linked prenatal exposure to altered maternal thyroid hormones and adverse child outcomes including ADHD, but these studies cannot establish cause. Regulators have retained the current ADI while the science continues to develop.
UK regulation restricts E218 to a narrow list: pate and similar products with a jelly coating, non-chocolate confectionery, dried-meat products (surface only), and liquid dietary food supplements. It is not permitted in everyday ambient grocery categories. Look for E218 or methyl p-hydroxybenzoate on the ingredients label.
Methylparaben used in food is manufactured synthetically from p-hydroxybenzoic acid and methanol, with no animal-derived inputs in the final product. It is generally considered vegan, though strict vegans may wish to verify their manufacturer's sourcing of the p-hydroxybenzoic acid starting material.
Last reviewed: 20 June 2026
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