Chemicals in Cosmetics: What to Know
- , by SANUSq Research team
- 7 min reading time
We scrutinise food labels, but rarely the ingredient lists on our shampoos, lotions and lipsticks. Some cosmetic ingredients are worth knowing about — here's a clear-eyed look, separating genuine concerns from the myths.
Cosmetics and personal-care products contain many synthetic ingredients, and some have raised legitimate health questions. It's worth being accurate, though: regulators like the EU and FDA do assess many of these, most are low-risk at the levels used, and the evidence varies a lot from ingredient to ingredient. A notable regulatory difference is real — the EU has banned or restricted well over a thousand cosmetic ingredients, while the US FDA has more limited pre-market authority over cosmetics — which is a fair reason to read labels rather than a reason to panic. Headlines about toxic chemicals in cosmetics tend to flatten that variation, treating a well-documented irritant and a suspected carcinogen as if they were the same thing. Here are the harmful ingredients in makeup and personal care most worth understanding.
Parabens in cosmetics: dangers, real and rumoured
Parabens are preservatives that stop microbial growth. They have weak oestrogen-like activity, which is why they've been scrutinised in relation to breast cancer.
One study detected parabens in samples of human breast tumour tissue (Darbre et al., 2004) — but it's important to note the study had no comparison with normal tissue, so detecting parabens does not show they cause cancer, and no causal link has been established.
Much of the online alarm about parabens traces back to that single detection study, and it is worth knowing what it did and did not measure before drawing conclusions from it.
The honest position: parabens are worth being aware of, and paraben-free options are easy to find if you prefer them, but the "parabens cause breast cancer" claim goes well beyond what the evidence supports.
Phthalates
Used as plasticisers and to carry fragrance, phthalates are endocrine-active in laboratory studies and some have been restricted in cosmetics for that reason. Human health effects at typical cosmetic exposures are still being studied. They're a reasonable ingredient to limit — particularly for pregnant women and young children — without treating them as an established serious hazard.
Triclosan
An antibacterial agent the FDA removed from consumer soaps, partly over concerns about antibiotic resistance and limited evidence of benefit. It persists in some toothpastes and other products, and the EU restricts it. Reducing exposure is sensible.
Lead (in some lipsticks)
Lead can occur as a trace contaminant in some lipsticks. Since there's no known safe level of lead, this is a genuine — if small — concern, and regulators monitor it. Choosing reputable brands and being mindful of products used by children is reasonable.
Fragrance
"Fragrance" or "parfum" on a label can represent a mix of many undisclosed ingredients, protected as trade secrets. For most people they're harmless, but they're a common cause of allergic reactions, skin irritation and headaches, and can be problematic for people with asthma or sensitivities — which is why fragrance-free options exist.
Formaldehyde and formaldehyde-releasers
This is one of the clearer concerns.
Formaldehyde is classified by the International Agency for Research on Cancer as a Group 1 carcinogen, and it can also cause skin and respiratory irritation (IARC).
Some cosmetics contain "formaldehyde-releasing" preservatives (such as DMDM hydantoin, diazolidinyl urea and quaternium-15) that release small amounts over time. Those prone to skin reactions in particular may want to avoid them.
SLS/SLES — and a myth worth correcting
Sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES) are foaming agents. Contrary to a persistent internet claim, SLS is not a proven carcinogen — it's a skin and eye irritant, which is a different (and much less alarming) thing. The genuine issue is that SLES can be contaminated during manufacturing with 1,4-dioxane, which IARC classes as a possible human carcinogen; responsible manufacturers reduce this through purification.
Mineral oil
Cosmetic-grade mineral oil is highly refined and regarded as safe by regulators; the contamination concerns you may read about relate to unrefined industrial grades, not the cosmetic grade used in skincare. It can feel occlusive and doesn't suit everyone's skin, but it isn't the toxin it's sometimes made out to be.
What "natural" and "clean" mean on a label
Very little, is the short answer, and it is worth knowing before paying a premium for either.
Neither "natural" nor "clean" has a settled legal definition in cosmetics, so a manufacturer can apply them fairly freely. "Chemical-free" is emptier still, since water is a chemical and so is every ingredient in every product ever made. Certified organic labels do mean something, because a certifying body sets and checks the standard, but the standard concerns sourcing and processing rather than whether an ingredient will suit your skin.
It is also worth retiring the assumption that plant-derived automatically means gentler. Essential oils and botanical extracts are among the more common causes of contact allergy in cosmetics, precisely because they are complex mixtures of active compounds. Fragrance allergens frequently come from plants.
The more useful habit than label-reading is patch testing. If you are trying something new, particularly with sensitive or reactive skin, apply a small amount to an inconspicuous patch for a few days before using it properly. A reaction to a specific ingredient is far more likely to affect you personally than any of the population-level concerns described above.
How to reduce your exposure sensibly
You don't need to fear your bathroom shelf. If you'd like to cut back on the ingredients above: read labels and favour shorter ingredient lists, choose fragrance-free or certified options where it matters to you, and use online ingredient databases to look up specific products. Whole-body health basics — a good diet, not smoking, sun sense — matter far more to your long-term health than any single cosmetic ingredient.
Frequently asked questions
Do parabens in cosmetics really cause cancer?
No causal link has been established. Parabens have weak oestrogen-like activity and have been detected in breast tissue, but detection isn't proof of harm, and regulatory reviews consider them safe at the low levels used. Paraben-free products are widely available if you prefer them.
Which cosmetic ingredients are genuinely worth avoiding?
The clearer concerns are formaldehyde-releasing preservatives (formaldehyde is a known carcinogen), trace lead, and 1,4-dioxane contamination in some SLES products. Fragrance is worth avoiding if you're prone to allergies. Many other ingredients are low-risk at normal exposures.
Is SLS in shampoo dangerous?
SLS is an irritant, not a proven carcinogen — the "SLS causes cancer" claim is a myth. It can dry or irritate skin and eyes, so people with sensitive skin may prefer to avoid it, but it isn't the serious hazard it's often portrayed as.
Are natural or "clean" cosmetics always safer?
Not automatically — "natural" isn't a regulated term, and some natural ingredients cause allergies too. The most reliable approach is reading ingredient lists, choosing products suited to your skin, and not assuming a marketing label guarantees safety.
References
- Darbre PD, Aljarrah A, Miller WR, et al. Concentrations of parabens in human breast tumours. J Appl Toxicol. 2004;24(1):5–13. PMID 14745841
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The team at SANUSq.
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The health information in this article is provided for educational purposes only. Consult your healthcare professional before making any medical decisions.
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