Benzene in sunscreens: two different stories that are being confused

Since 2021, benzene has periodically returned to the headlines: first in hand sanitizers, then sunscreens, then dry shampoos and spray deodorants, and more recently acne treatments. It is classified as carcinogenic to humans and associated with leukemia, so the concern is legitimate. The way it is reported, much less so.

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First story: the 2021 sunscreens

A U.S. independent laboratory analyzed nearly three hundred batches of sunscreens and after-sun products from dozens of different companies and found detectable benzene in about a quarter of the samples, in some cases above the limit of 2 parts per million that the U.S. authority considers conditionally tolerable. Recalls followed, some very extensive, particularly involving aerosol products.

The decisive point is that none of those companies had added benzene to the formula. The benzene came from outside: largely from aerosol propellants, such as isobutane and propane, which can carry it along if they are not purified sufficiently. The same mechanism explained the subsequent findings in dry shampoos and spray antiperspirants—in other words, other products in aerosol cans.

There is also a second, less widely reported and more technical route: some raw materials can be produced using benzene as a process solvent and retain traces of it. In the following years, the U.S. authority worked on this by requesting the reformulation of products that used those ingredients.

So: the issue was not what was listed in the INCI, but the quality of the supply chain and batch testing. It is a serious and solvable problem, and it does not concern sun protection as such.

Second story: benzoyl peroxide

Here, the mechanism is completely different, and it needs to be explained clearly because it is why the issue has returned to the spotlight.

Benzoyl peroxide has been one of the most widely used active ingredients against acne for almost a century. The problem is that it can degrade, generating benzene, and the reaction is accelerated by heat. This is not contamination entering from outside: it is the chemistry of the active ingredient itself.

In March 2025, the U.S. authority published the results of its own tests on 95 acne products: more than 90% contained no detectable benzene or only extremely low levels, while six products showed elevated levels and were recalled at the point of sale, along with a seventh reported by the manufacturer itself.

Two points that often disappeared from social media summaries. First: the authority stated that, even with daily use for decades, the risk of developing cancer because of the benzene found in those products remains very low. Second: third-party tests had reported much more widespread contamination, and the agency noted that unvalidated analytical methods can produce results that do not reflect the actual contamination.

This does not mean that the independent laboratories were wrong: it means that measuring benzene is difficult and that the number depends on the method. And it is a lesson worth remembering whenever you read an analytical result about a cosmetic product.

«In the first case, something entered the product. In the second, the product transformed. They are two different defects and require two different responses.»

The most useful finding

A study published in JAMA Dermatology in 2025 showed that benzene formation in products containing benzoyl peroxide increases with high-temperature processing and can be reduced by modifying the formulation, for example by adding antioxidants such as BHT.

In practice, and this applies to those reading, not to those who formulate:

1. Heat is the variable. A product left in the car in summer, on the beach under the sun, or on the bathroom windowsill is not in the conditions for which it was tested.
2. Expiration really matters. In this category, it is not a formality: degradation is progressive.
3. Format matters. Most sunscreen recalls involved aerosol cans, where the propellant is the source of the problem.

The third is why we have never put a sunscreen in an aerosol can in the range, and chose a single-dose format that you use up and take with you instead of leaving it in the car:

What Europe says, which is the part that concerns you

The two incidents originated in the United States, and that changes things because the regulatory framework is not the same.

Benzene is prohibited as an ingredient in cosmetics in Europe: it is included in the list of prohibited substances under Regulation 1223/2009. The presence of unintentional traces is regulated separately and permitted only if technically unavoidable and if the product remains safe: in other words, it must be justified and assessed; it cannot simply be accepted.

There is also a difference that has been little explained in Italy. Benzoyl peroxide is not permitted in European cosmetics for treating the skin: here, anti-acne products containing it are medicines, with the pharmaceutical quality, batch traceability, and distribution channel that follow. So the American news about over-the-counter products concerned a category that, in Italy, is sold in pharmacies and is subject to different rules.

If you have mild blemishes and are looking for a cosmetic approach, one exists and it does not involve that active ingredient:

If the acne is genuine, inflammatory, with nodules or scarring, cosmetics are not the answer and the right place is the dermatologist's office. These are two situations that can be confused in the mirror but distinguished quickly at the counter: pharmacies and parapharmacies that distribute LeLang also have the practical ability to verify batches and expiry dates, which is exactly what is needed on this issue.

The collateral damage that is underestimated

In the summer of 2021, I heard more than one person say they would avoid sunscreen to avoid the risk of benzene. That is the worst possible outcome of accurate news communicated badly.

Because the comparison must be between two risks, not between a risk and zero. On the one hand, contamination present in some batches, largely linked to aerosols, measured in parts per million and for which the US authority itself estimated a very low risk. On the other, unprotected ultraviolet exposure, whose link to skin cancer and photoaging has not been in question for decades.

There is no symmetry between the two things. And this is the same pattern as the chemophobia I wrote about in the summer: a well-told risk is more frightening than the actual risk.

How I handle it, in four lines

• I don't buy sunscreen in aerosol cans, and if I do, I don't leave them in the heat.
• I follow expiry dates and the period after opening, especially for sunscreens and anti-acne products.
• I prefer a channel that can tell me which batch the product I'm buying comes from.
• I apply sunscreen every day, and this is not a choice between two risks: it is the only item on the list with a proven effect.

What I really think

That independent laboratories have done something useful, that recalls are a sign of a system that works rather than one that is collapsing, and that the cosmetics industry has a duty to monitor its raw materials with ever-increasing rigor.

And that, in this case, public communication caused more damage than the benzene. Because putting a trace contaminant in some batches on the same footing as giving up photoprotection means pushing people toward the worst choice for a reason that sounded scientific.

The way to respond to a quality problem is not to stop protecting yourself. It is to demand better-made products.