Every morning I do roughly what you do. Brush my teeth, wash my face, put on sunscreen. None of it feels like a chemistry experiment.
I've spent years on the other side of that routine — three of them making the raw ingredients that end up in products exactly like these. I won't pretend the science is settled where it isn't. But I've read the literature that sits behind your bathroom shelf, and one recent paper has been dominating the conversation.
Here is what the review actually says, translated into plain language, and what it means for the person standing at the bathroom sink.
The paper and the picture it paints
The paper is called The Dark Side of Beauty, published in 2024 by Abdullah M. Alnuqaydan in Frontiers in Public Health. It is a review — the author gathered a large body of existing toxicological studies and synthesized them into a single map of the industry.
He writes that the current state of cosmetic safety is deeply flawed, heavily under-regulated, and putting public health at risk.
The picture is a worried one: he explicitly connects long-term use of synthetic, chemical-based cosmetics to respiratory conditions, neurological disorders, endocrine disruption, and cancer. This is not a call for mild caution.
What the review says is in the bottle
When the paper breaks down ingredients of concern, it doesn't point to exotic or rare chemicals. It points to the ordinary machinery of the products we use every day.
Keep shampoo from growing mould, help fragrance linger. The review argues they can bind to hormone receptors, primarily mimicking estrogen, potentially disrupting reproduction and thyroid function.
1,4-dioxane forms as a manufacturing byproduct in liquid soaps and shampoos, not added on purpose. Formaldehyde-releasing preservatives in some hair products and nail polishes are classed as known human carcinogens.
Sometimes present to enhance shine or brightening. The author warns these can pass through skin into the bloodstream, and long-term low-dose exposure may alter cellular function.
Shrinking ingredients to microscopic scale makes sunscreens less chalky, creams absorb faster. The review cautions particles this small may pierce skin and trigger cellular changes science doesn't yet fully understand.
The daily pile-up
The idea the author returns to most is what he calls the mixture effect. Almost every safety test looks at a single ingredient, alone, at a measured dose. That is not how anyone uses cosmetics — shampoo, conditioner, deodorant, toothpaste, sunscreen, moisturiser, every day, for decades.
He writes that these individually approved chemicals can act synergistically, interacting to become more toxic, or more carcinogenic, than any of them would be alone.
This cumulative, daily exposure is, in his account, a reality that current safety testing largely ignores.
The regulatory blind spot
You might assume a product cannot reach the shelf unless a government agency has proved it safe. The review challenges that assumption, with its clearest example drawn from the United States, where the cosmetic industry operates largely on self-regulation and the FDA does not require pre-market approval for cosmetic products.
of companies, the author estimates, prioritise profit and marketability over thorough safety evaluation
of products, on his reading, undergo rigorous pre-market carcinogenicity testing
What the author asks of us
Papers like this are uncomfortable because they remove the assumption that someone else is entirely handling our safety. The author is not telling you to empty your bathroom cabinet into the bin today.
His conclusion is a call for change at the level of regulation: mandatory, strict pre-market testing, and in particular testing of how chemical mixtures behave together rather than one compound at a time. Until that happens, he argues, more of the burden of safety sits with the consumer than most people realise.
In practice: reading ingredient labels with a more critical eye, asking brands for transparency, and understanding that the products we use daily carry a health question the author believes we are only beginning to map.
This review is one voice in a much larger scientific conversation. It doesn't settle the question of cosmetic safety, nor does it claim to. Instead, it gathers existing evidence and argues that current approaches to testing and regulation may leave important gaps. Other researchers will agree with some of its conclusions, challenge others, and build new evidence over time. That is how science moves forward, not through a single paper, but through many studies that gradually sharpen our understanding. Our role at The Ingredient Lab is simply to make that conversation easier to follow.
Source
– Alnuqaydan, A.M. (2024). The dark side of beauty: an in-depth analysis of the health hazards and toxicological impact of synthetic cosmetics and personal care products. Frontiers in Public Health, 12, 1439027. DOI: 10.3389/fpubh.2024.1439027
This is a translation of one review, not medical advice. We reach no verdict on any brand and name none. The Ingredient Lab takes no advertising and holds no affiliate links. Spotted something we've got wrong? science@theingredientlab.org