E-numbers / Preservatives / E217
also: Sodium propyl para-hydroxybenzoate · Sodium salt of propylparaben
A synthetic preservative from the paraben family, banned from food in the UK and EU since 2006 following reproductive concerns in animal studies.
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Parabens weakly mimic the hormone oestrogen.
Why it’s worth knowing. Parabens weakly mimic the hormone oestrogen. Propylparaben was withdrawn from UK and EU food use because regulators could not establish a level at which it had no effect on male reproductive organs in animal tests. It may still appear in imported foods and remains permitted in cosmetics and some medicines.
The sodium salt of propyl p-hydroxybenzoate, a synthetic ester of para-hydroxybenzoic acid. The sodium salt form is more water-soluble than propylparaben (E216) itself, which makes it easier to disperse in water-based food products. Both share the same active molecule once dissolved.
Inhibits the growth of moulds and yeasts by disrupting their cell membranes and interfering with enzyme function. Less effective against bacteria than against fungi. Used at low concentrations to extend shelf life by preventing microbial spoilage.
Historically used in bakery products, confectionery fillings, sugar-coated goods, and fruit-based preparations. It remains permitted in foods in the United States, where it still appears in tortillas, packaged baked goods, and cake icing. It is also permitted in cosmetics and pharmaceutical preparations across the UK and EU. On a label it appears as 'E217' or 'sodium propyl p-hydroxybenzoate'. Since it is banned from UK and EU food, you should not encounter it on a UK food label, but it may appear on imported products or parallel imports.
A 2002 study fed propylparaben to young male rats and found reduced sperm production and lower testosterone at the lowest dose tested, which was close to the previously acceptable daily intake. EFSA reviewed this finding and concluded there was no dose at which the additive clearly caused no harm to the male reproductive system, making it impossible to set a safe intake level.
Young male rats fed propylparaben showed dose-dependent reductions in daily sperm production and cauda epididymal sperm reserves. Serum testosterone also fell at the highest dose. Effects appeared at the lowest tested dose of approximately 10mg per kilogram of body weight per day.
EFSA's Scientific Panel on food additives reviewed the para-hydroxybenzoates and concluded it could not recommend a specific ADI for propylparaben because there was no clear no-observed-adverse-effect level for the male reproductive endpoint. This exclusion from the group ADI effectively made continued food authorisation untenable.
Two large, rigorously controlled studies published in 2013 tested propylparaben in juvenile male rats at doses up to 1000mg per kilogram per day and found no effects on sperm, reproductive organs, or testosterone. A 2017 scientific review argued that the original Oishi study had anomalous control values and that the EU ban was not well-founded by the totality of evidence. The EFSA ban, however, remains in place.
Oral administration of propylparaben for 8 weeks starting in juvenile male Wistar rats found no effects on reproductive organ weights, sperm count or motility, or hormone levels at any dose up to 1000mg per kilogram per day. NOAEL was set at 1000mg/kg/day.
A regulatory science review argued the Oishi 2002 control testosterone values were approximately four times higher than historical norms for the rat strain used, and that raw data were not available for audit. The review concluded the EU assessment was compromised and called for reassessment using auditable GLP data.
All parabens, including propylparaben, show weak oestrogen-like activity in cell-based laboratory tests. Propylparaben can bind to oestrogen receptors and stimulate oestrogen-responsive genes in human breast cancer cells, though at concentrations far higher than oestrogen itself. Whether this laboratory activity translates to meaningful effects in people at food-relevant exposures is not established.
Propylparaben stimulated expression of oestrogen-regulated genes and increased proliferation in MCF-7 human breast cancer cells at concentrations of 1 micromolar and above, through an oestrogen receptor-mediated mechanism confirmed by an anti-oestrogen blocking agent.
A review of parabens' endocrine toxicity found that parabens show weak oestrogenic activity in laboratory and animal test systems, that they can penetrate human skin intact without full breakdown, and that intact parabens have been detected in human tissues. The review concluded the potential human health risks warranted further scrutiny.
A 2004 study detected parabens including propylparaben intact inside breast tumour samples from 19 of 20 patients. The authors noted this was significant because parabens had previously been assumed to break down rapidly in the body. The study found an association, not a cause, and its authors were explicit that no causal link to cancer could be drawn.
Intact parabens were detected in tissue samples from 19 of 20 human breast tumours by high-pressure liquid chromatography and tandem mass spectrometry. The study could not identify either the route of entry or the source of the parabens, and no causal link to tumour formation was established.
A 2026 study tracked paraben levels in pregnant women's urine across pregnancy and then assessed their children's behaviour using standardised checklists at ages two, three, and four. Higher paraben mixture exposure was linked to higher scores for externalising behaviours, particularly at age two. The findings are observational: they show an association, not proof that parabens caused the behaviour differences.
In a prospective cohort study, prenatal exposure to a paraben mixture was associated with higher scores for externalising behaviours and oppositional defiant problems in children at ages 2 and 3. Propylparaben individually was associated with reduced withdrawn behaviour scores in males at age 2. Effects were strongest in male children and at younger ages.
The EU Scientific Committee on Consumer Safety reviewed all available evidence in 2021 and concluded that while some data suggested potential endocrine effects, the evidence was not sufficient to formally classify propylparaben as an endocrine-disrupting substance. It remains banned from food in the EU and UK regardless of this finding, because the food ban was triggered by the reproductive endpoint in the 2004 EFSA review.
The SCCS concluded in 2021 that the available data provided some indications of potential endocrine effects for propylparaben but that the current level of evidence was insufficient to regard it as an endocrine-disrupting substance or to derive a toxicological point of departure based on endocrine-disrupting properties.
Since E217 is not permitted in UK or EU food, you will not see it on UK food labels in normal circumstances. For imported foods from the United States or other countries where it remains permitted, look for 'propyl paraben', 'propylparaben', or 'sodium propyl p-hydroxybenzoate' in the ingredients list. People who are pregnant may wish to minimise overall paraben exposure given early observational evidence linking prenatal paraben levels to child behavioural outcomes, though this research is not yet conclusive.
The science around propylparaben is genuinely contested. The EU ban rests on a 2002 rat study whose control values have since been criticised as anomalous, and two larger, better-controlled studies found no reproductive harm at any dose tested. The EU food ban stands regardless. On endocrine disruption, lab tests show parabens can weakly activate oestrogen receptors, and parabens have been detected intact inside human breast tumour tissue, but no study has established that food-level exposure causes hormone-related harm in people. The 2021 EU Scientific Committee on Consumer Safety reviewed all available evidence on endocrine effects and concluded the data were insufficient to formally classify propylparaben as an endocrine disruptor. Observational studies in humans suggest possible links between prenatal paraben exposure and child behaviour, but these cannot distinguish cause from coincidence. The science is live and disputed, not settled in either direction.
Yes. E217 (sodium propylparaben) is not an authorised food additive in the UK or EU. It was removed from the EU permitted list in 2006 following EFSA's conclusion that it was not possible to set a safe daily intake level for the reproductive effects seen in animal tests. The UK retains this position. It remains permitted in cosmetics and some pharmaceutical products, but not in food.
The 2004 EFSA review concluded that the 2002 Oishi rat study showed effects at the lowest dose tested, meaning no safe level could be identified. Two later GLP-compliant studies (2013) found no reproductive harm at doses up to 100 times higher, and a 2017 scientific review challenged the methodology of the original study. EFSA has not formally re-evaluated propylparaben for food use since the ban; the precautionary withdrawal therefore remains in place despite the conflicting evidence.
No UK or EU food product is permitted to contain E217. It was historically used in bakery goods, confectionery fillings, and fruit-based food products. It is still found in some US food products including tortillas, packaged cakes, and icings. If you buy imported food from the United States or other non-EU/UK markets, check the ingredients list for 'propyl paraben', 'propylparaben', or 'sodium propyl p-hydroxybenzoate'.
Yes. Sodium propylparaben is a synthetic chemical and does not contain any animal-derived ingredients.
Last reviewed: 20 June 2026
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