‘Far from being a rock or island … it turns out that the best metaphor to describe the human body is ‘sponge’. We’re permeable,” write Rick Smith and Bruce Lourie in their book Slow Death By Rubber Duck: The Secret Danger of Everyday Things. While the permeability of our cells is key to being alive, it also means we absorb more potentially harmful substances than we realise.
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Studies have found a number of chemical residues in human breast milk, urine and water systems. Many of them are endocrine disruptors, which can interfere with the body’s natural hormones. “They can mimic, block or otherwise disrupt normal hormone function, leading to adverse health effects,” says Dr Shanna Swan, professor of environmental medicine and reproductive health at the Icahn School of Medicine at Mount Sinai, New York. We (often unknowingly) ingest, inhale or otherwise absorb them, and while toxicity depends on dosage, the reality is that a lot of us are exposed to them daily.
So what to do about it? There are apps that will give you information about the ingredients in products, such as Yuka, Think Dirty and EWG’s Healthy Living, but there are some key “nasties” worth knowing about. Because science is always evolving, navigating these issues can be tricky – even for the experts. That’s why many specialists recommend looking at your overall lifestyle and habits, rather than fixating on individual substances in isolation. The list that follows is far from exhaustive, but it highlights 15 ingredients that science suggests may pose risks to our health.
Illustration: Ben Wiseman/The Guardian
Cosmetics
Phthalates
This group of chemicals is found in fragrances, plastic (including children’s toys) and other cosmetics and personal care products – such as hairspray and nail polish. Some phthalates are deemed endocrine disruptors “linked to preterm birth, fertility issues, early puberty and some cancers”, says Alexa Friedman, a senior scientist at non-profit health organisation Environmental Working Group. Swan adds that they can lower testosterone levels and increase our oestrogenic response, in turn affecting sperm, egg health and fertility, and increasing the risk of miscarriage and birth defects. While some are considered safer than others at low doses, many are still linked with negative health concerns and/or are currently under-researched.
To reduce exposure, avoid vague “fragrance” labels and ingredients ending in “phthalate”, such as dibutyl phthalate or diethyl phthalate. Brands such as Ilia, Westman Atelier, Refy, Merit Beauty, Weleda, Olaplex, Charlotte Tilbury and Paula’s Choice avoid using them, but if in doubt check the EWG’s Skin Deep cosmetics database to learn exactly what’s in every formula you use.
Parabens
Used as preservatives in makeup, skincare, haircare and some processed food, parabens extend shelf life and prevent microbial growth. Long-chain parabens, such as propylparaben, butylparaben and isobutylparaben, are endocrine disruptors that mimic oestrogen and “may contribute to hormonal imbalances, reproductive harm, asthma, allergies, obesity and possibly hormone-sensitive cancers later in life”, says Dr Federica Amati, head nutritionist at Zoe, the personalised nutrition app.
Though some argue low doses are safe, many brands now offer paraben-free options. Look to Drunk Elephant, The Ordinary, Paula’s Choice, Tata Harper and Living Proof, as well as most CeraVe and La Roche-Posay formulas too.
Fragrance
They may smell good, but many fragrance chemicals are phthalates or volatile compounds that release gas into the air. Often not fully disclosed on labels, they can trigger allergies and disrupt hormones, says Amati. One example, Lilial (butylphenyl methylpropional) was widely used in cosmetics until it was banned in the UK and EU in 2022. “Beware of ingredient lists that use the words ‘fragrance’ or ‘parfum’ as they can hide phthalates and other chemicals,” advises Amati. Opt for fragrance-free skincare (Avène and Dermatica do great formulas, while Bioderma’s Sensibio and La Roche-Posay’s Toleriane lines are also good options) and haircare (such as Philip Kingsley’s No Scent No Colour shampoo) and again, always read the label.
Formaldehyde or formaldehyde-releasers
“Used in nail and hair products as preservatives, formaldehyde is a known carcinogen and can cause respiratory irritation and skin allergies, while formaldehyde-releasing preservatives are associated with adverse skin reactions,” says Friedman. Black and Latino women, who often use hair relaxers, face higher exposure and potentially health risks over time.
For safer haircare options, try formaldehyde-free keratin treatments from brands such as Kerasilk and Cezanne. Nail strengtheners – at home or in salon – often contain formaldehyde, so check before use, although BIAB and CND Shellac are formaldehyde-free. As well as formaldehyde itself, watch out for ingredients such as DMDM hydantoin, diazolidinyl urea, quaternium-15 and sodium hydroxymethylglycinate, which can also be found in self-tanners, makeup products such as blush, mascara, concealer and foundation, shampoo and conditioner, and skincare formulas too.
Oxybenzone
Oxybenzone, a chemical filter in some sunscreens, is an endocrine disruptor and harmful to coral reefs. Cosmetic biochemist Nausheen Qureshi explains that it is absorbed by the skin and converts UVA rays to prevent damage – its intended function – but there are nonetheless concerns about (and ongoing research into) its impact on our health. It may potentially affect our thyroid and reproductive hormones, and affect kidney and immune system function. Friedman recommends looking for EWG-verified sunscreens, which avoid harmful ingredients such as oxybenzone, but brands such as Medik8 offer effective and safe options too. Mineral sunscreens that utilise zinc oxide or titanium dioxide are a good alternative because they sit on the skin and reflect UV light (without absorption) instead.
Food
Artificial sweeteners
“Artificial sweeteners, like sucralose and saccharin, can disrupt gut microbiota and impair glucose metabolism, potentially leading to metabolic disorders like diabetes,” says Amati. These low-calorie sugar substitutes are often found in products that are labelled “diet” or “sugar-free”. Studies also link intake with increased risk of cardiovascular disease and unnecessary appetite stimulation. When buying supermarket products, be wary of low-sugar marketing claims and prioritise eating whole foods (raspberries are a great high-fibre, low-sugar snack) over processed foods and diet drinks. Swap fizzy beverages (which are often full of artificial sweeteners) for Dalston’s Soda or Momo’s raw and unfiltered kombucha, which is also great for gut health.
High-fructose corn syrup
High-fructose corn syrup (HFCS) is a sweetener commonly found in processed foods, fizzy drinks, sweets, sauces, breakfast cereals, baked goods and even certain yoghurts and flavoured dairy products in the UK, and especially in the US. It is inflammatory, “disrupts the metabolism and contributes to insulin resistance, blood sugar instability, obesity and type 2 diabetes,” says Rhian Stephenson, nutritionist, naturopath and founder of Artah, which sells supplements and nutrition programmes. “It also offers little nutritional value and negatively affects energy levels, hormones and metabolic health.”
In the UK, HFCS may appear on labels as glucose-fructose syrup or isoglucose, but elsewhere it goes by other names, such as maize syrup. Stephenson advises reading full ingredient lists, “not just the front label, because marketing claims – such as ‘natural’ or ‘low fat’ – can be misleading,” she says. “In fact, they are usually a warning sign.” For some extra assistance, Amati recommends the Zoe processed food risk scale, a science-backed tool that offers guidance on what’s in processed foods. Ultimately, cooking whole foods at home is the best way to avoid HFCS and similar additives.
Emulsifiers
Widely used to improve the texture and shelf life of packaged foods, emulsifiers have “been shown (in animal studies) to cause gut inflammation and glucose intolerance, and many worsen intestinal diseases like ulcerative colitis”, says Amati. It is found in products such as ice-cream, mayonnaise, chocolate, packaged bread and oat milk (common examples include polysorbate 80, carboxymethyl cellulose or CMC and carrageenan). Emulsifier-free supermarket buys include Jason’s Sourdough (which also doesn’t contain sweeteners), Plenish’s Oat Milk, Yeo Valley’s Organic Vanilla Ice-Cream and Kallo’s Belgian Milk Chocolate Organic Rice Cake Thins. While currently deemed safe in small amounts, emulsifiers are worth watching as research in humans evolves.
Nitrites
Whether it’s bacon, salami or hotdogs, most processed meats are preserved using nitrites. These can form carcinogenic nitrosamines in the body, and have been scientifically linked to an increased risk of colorectal cancer, rates of which are rising globally. The World Health Organization advises limiting intake, and to be particularly wary of heating them above 130C, which is when nitrosamines can form – and have been linked to stomach and bowel cancer.
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Artificial food dyes
Artificial food dyes are added to food and drink to create specific colours. While the most concerning culprits – red 3 (E127) and red 40 (E129) – are no longer widely used in the UK, some are, including ponceau 4R (E124), sunset yellow (E110), quinoline yellow (E104), carmoisine (E122) and tartrazine (E102), but hold Food Standards Agency warnings. They are still considered safe overall, but are linked to “neuroinflammation [potentially leading to diseases such as Alzheimer’s and Parkinson’s], hormone disruption and behavioural issues such as hyperactivity and attention difficulties, especially in sensitive individuals like children,” says Stephenson. “There are concerns about their impact on developing brains and nervous systems.”
You’ll find them in some fizzy drinks, sweets, canned fruit, jellies, mushy peas, ready meals and products imported from the US, including various sweets. Most food companies in the UK now avoid them. However, if they are used, it is a legal requirement that the products carry a warning (“may have an adverse effect on activity and attention in children”), so check the label.
Trans fats
Trans fats – especially those that are artificially made – raise LDL (bad) and lower HDL (good) cholesterols, and are linked to chronic inflammation and heart disease. They can also “disrupt hormone balance, impair insulin sensitivity, and affect everything from mood and metabolism to fertility and menstrual health,” says Stephenson. Found in ultraprocessed foods, such as frozen pizza, chips, doughnuts, cakes and margarine, they also contribute to the unhealthy visceral fat that builds up around key organs such as the liver and intestines, which raises inflammation and increases the risk of a number of diseases. If “partially hydrogenated oil” is listed on the label, take it as an immediate red flag, while interesterified fats, hydrogenated vegetable oil and shortening (a type of fat used to create crumbly pastry) are other warning signs, says Stephenson.
Illustration: Ben Wiseman/The Guardian
Kitchen
Pfas
Own a Teflon pan? Then you will have encountered Pfas (per- and polyfluoroalkyl substances), a family of “forever chemicals” that are in some non-stick coatings. They are also used for water- or smudge-resistance in cosmetics, textiles and outdoor clothing. “Pfas degrade incredibly slowly,” explains Jonatan Kleimark, head of corporate sustainability at ChemSec. This allows them to build up in the body and the environment, which is worrying as they are carcinogenic and can disrupt our hormones, reduce immune function and cause reproductive issues.
To avoid them, swap non-stick pans for carbon, ceramic or stainless steel: brands such as Our Place and Le Creuset offer highly Instagrammed, Pfas-free pots and pans. Many brands now make it clear that their products are Pfas-free, so keep an eye out. In makeup and skincare, beware of ingredients that feature “fluor” somewhere in their name (see: perfluorooctanesulfonic acid), especially if they are in long-wear or waterproof products as these are often Pfas, says Kleimark.
BPA
An industrial chemical used to make rigid plastics, bisphenol A (or BPA) is a “well-studied endocrine disruptor associated with hormone-sensitive diseases (such as endometriosis, polycystic ovary syndrome, ovarian, breast, prostate and thyroid cancers and postpartum depression) and metabolic disorders,” says Amati. It also affects cognitive function and raises risk of obesity. Like Pfas, it accumulates in the body over time, increasing long-term disease risk. Research in 2020 found BPA in the urine of 92% of adults in 11 European countries.
Though Tupperware is BPA-free, the substance is still found in many plastic containers, refillable drinks bottles and tin can linings. (The EU banned it in food-contact materials in 2025, but the UK has not done the same.) To avoid it, switch to glass containers (VonShef and Pyrex are good options), buy BPA-free water bottles, such as Ocean Bottle, and look for a “BPA-free” label on cans. If the can’s recycling code is 3 or 7 (see the green triangle), chances are it contains a BPA lining.
Triclosan
There are a number of ingredients in cleaning products that can affect human health. Triclosan, an antimicrobial agent that’s linked to oxidative stress, hormone disruption and genotoxicity (the ability to damage our genes), is worth avoiding. Brands such as Dr Bronner, Method and Ecover offer triclosan-free formulas.
VOCs
Volatile organic compounds (VOCs), found in ingredients such as denatured alcohol (meths) and some fragrances, are linked to cancer and respiratory issues. Choose fragrance-free cleaning products, such as those from Purdy & Figg, Kit & Kin and Bio-D, which avoid triclosan, parabens and other concerning chemicals, as well as formulas such as M&S’s Sensitive Multi-Surface Cleaner and The Lab Co’s Fragrance Free Washing Up Liquid.
