The average person applies 10-15 cosmetic products to their skin every day — from moisturiser and sunscreen to shampoo and deodorant. Most ingredients in these products are safe. But some have attracted regulatory scrutiny, published safety concerns, or outright bans in certain markets.
Here are 10 ingredients commonly found in UK skincare and cosmetic products that are worth understanding. We've focused on what the evidence actually says — not internet scare stories.
1. Formaldehyde and Formaldehyde Releasers
Risk level: High · Found in: some nail polishes, hair straightening treatments, shampoos
Formaldehyde is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC). While formaldehyde itself is rarely listed on ingredient labels today, several preservatives slowly release it over time: DMDM hydantoin, quaternium-15, imidazolidinyl urea, and diazolidinyl urea.
The EU restricts formaldehyde in cosmetics to 0.1% (except in nail hardeners at 5%), and products exceeding 0.05% must carry a warning label. If you see any of these formaldehyde-releasing preservatives on a label (learn how to read cosmetic labels), the product will release small amounts of formaldehyde throughout its shelf life.
2. Oxybenzone (Benzophenone-3)
Risk level: High · Found in: chemical sunscreens, lip balms with SPF
Oxybenzone is a UV filter that absorbs into the bloodstream — an FDA study detected it in blood within 2 hours of application at concentrations exceeding the FDA's safety threshold. It has been detected in breast milk and amniotic fluid. Research has shown weak endocrine-disrupting activity, and it is harmful to coral reefs — Hawaii and Palau have banned sunscreens containing it.
Safer UV filter alternatives include zinc oxide and titanium dioxide (mineral sunscreens), which sit on the skin surface rather than being absorbed.
3. Parabens (Methyl, Propyl, Butyl, Isobutylparaben)
Risk level: Medium · Found in: moisturisers, shampoos, makeup, deodorants
Parabens are preservatives that mimic oestrogen in laboratory studies. Butylparaben and propylparaben show stronger oestrogenic activity than methylparaben. The EU has restricted butyl and propylparaben concentrations and banned them entirely in products for children under 3 (nappy area). Many UK brands have voluntarily reformulated to be paraben-free as part of the clean beauty movement.
The scientific picture is nuanced: methylparaben at permitted concentrations is generally considered safe by European regulators. The concern increases with propyl and butylparaben, particularly during pregnancy.
4. Fragrance / Parfum
Risk level: Medium · Found in: almost everything — moisturisers, body wash, deodorant, laundry products
The word "Parfum" or "Fragrance" on a label can represent a blend of dozens to hundreds of individual chemicals. Under EU and UK law, manufacturers only need to disclose 26 specific fragrance allergens if they exceed certain concentrations — everything else can be hidden under the umbrella term. Fragrance is one of the top five causes of contact dermatitis globally.
If you have sensitive skin, "fragrance-free" is different from "unscented" — unscented products may still contain masking fragrances.
5. Sodium Lauryl Sulfate (SLS)
Risk level: Medium · Found in: shampoos, body wash, toothpaste, facial cleansers
SLS is a surfactant — it creates the foam and lather in cleansing products. It is not a carcinogen despite persistent online claims. However, it is a known skin and eye irritant that strips natural oils from the skin. For people with eczema, rosacea, or sensitive skin, SLS can worsen symptoms. Sodium laureth sulfate (SLES) is a milder alternative, though it can be contaminated with 1,4-dioxane during manufacturing.
6. BHT (Butylated Hydroxytoluene)
Risk level: High · Found in: lip products, moisturisers, sunscreens, hair products
BHT is a synthetic antioxidant that prevents oils from going rancid. It is permitted in the EU at restricted concentrations but has been flagged as a possible endocrine disruptor. Some studies have found it can cause skin sensitisation at higher concentrations. Many brands have switched to tocopherol (vitamin E) as a natural alternative.
7. Coal Tar
Risk level: High · Found in: anti-dandruff shampoos, psoriasis treatments
Coal tar is classified as a known human carcinogen by IARC. It is banned in EU cosmetics but still permitted in the UK in certain medicated products. If you use coal tar shampoo for dandruff, consider alternatives containing zinc pyrithione, ketoconazole, or salicylic acid — all of which are effective without the carcinogen classification.
8. Phthalates (Dibutyl Phthalate / DBP)
Risk level: High · Found in: nail polishes, some fragrances
DBP is a plasticiser banned in EU cosmetics due to strong evidence of endocrine disruption and reproductive harm. It is still permitted in some non-EU markets. Check nail polishes for "3-free" or "5-free" labels — these indicate the product is free from the most concerning nail polish chemicals including DBP, toluene, and formaldehyde.
9. Methylisothiazolinone (MIT) and CMIT
Risk level: High · Found in: wet wipes, shampoos, liquid soaps, makeup removers
MIT was widely adopted as a "safer" alternative to parabens — but it turned out to be one of the most potent skin sensitisers in cosmetics. The EU banned MIT in leave-on products in 2016 and restricted it in rinse-off products. If you developed a skin allergy to a product in the 2010s, there is a reasonable chance MIT was the culprit.
10. Chemical UV Filters (Octinoxate, Homosalate, Octocrylene)
Risk level: Medium · Found in: sunscreens, moisturisers with SPF, foundations with SPF
Several chemical UV filters have come under scrutiny: octinoxate (ethylhexyl methoxycinnamate) penetrates skin and has shown weak hormonal activity; homosalate has been recommended for lower maximum concentrations by the EU Scientific Committee; octocrylene can degrade into benzophenone over time.
Mineral sunscreens using zinc oxide or titanium dioxide remain the gold standard for safety — they reflect UV rather than absorbing it, and do not penetrate the skin significantly.
How to Use This Information
Don't panic about your current products — the dose makes the poison, and all these ingredients are used at regulated concentrations. Instead:
- Scan products with IngredScan to see which ingredients are in your cosmetics and their risk ratings
- Prioritise changes for products that stay on your skin longest (moisturisers, sunscreens) over rinse-off products (shampoo, body wash)
- During pregnancy, pay particular attention to retinol, salicylic acid (at high concentrations), parabens, and chemical UV filters
- For sensitive skin, look for fragrance-free, SLS-free formulations
Remember: "natural" does not automatically mean safe, and "synthetic" does not automatically mean harmful. The evidence for each ingredient should be assessed individually.