Is sunscreen safe, and does it prevent skin cancer? What the evidence shows

A long-running trial found daily sunscreen cut skin cancers, while FDA research showed some ingredients get into the blood. Here is what each finding means, and what the FDA changed in 2026.

A person sitting on sand rubbing sunscreen into their leg.

Summary

In an Australian trial of 1,621 adults, daily sunscreen users had half as many melanomas over the following decade.
The same trial found regular sunscreen use prevents squamous cell skin cancer long term.
An FDA study found six common sunscreen chemicals reach the blood, above a level that triggers more safety testing.
The study's authors said the blood levels are not a reason to give up sunscreen.
In September 2026 the FDA removed two older ingredients, PABA and trolamine salicylate, from its approved list.

Sunscreen gets two very different kinds of headlines. One says it prevents skin cancer; the other says its chemicals soak into the bloodstream. Both are based on real research, and they answer different questions.

The strongest trial evidence shows that regular sunscreen use prevents some skin cancers, including melanoma, the most dangerous kind. Research by the US Food and Drug Administration (FDA) shows some ingredients are absorbed into the blood, which is why it has asked for more safety data. Absorption is not the same as harm, and in 2026 the FDA acted on the ingredients it judged unsafe.

What skin cancer is

MedlinePlus explains that the two most common types are basal cell cancer and squamous cell cancer, and that melanoma is more dangerous but less common. Skin cancer is more common in people who spend a lot of time in the sun or have been sunburned, have light-colored skin, hair and eyes, or have a family history of it.

Ultraviolet light from the sun damages skin cells over time, which is why sun protection has been the focus of prevention. Sunscreen is one part of that, alongside shade, clothing and limiting time in strong sun.

Does sunscreen prevent skin cancer?

The clearest test is a randomized trial in Nambour, a town in subtropical Queensland, Australia. In 1992, 1,621 randomly selected residents aged 25 to 75 were assigned to daily sunscreen on the head and arms or to use it as they chose, until 1996.

The researchers kept following them, and reported the results in the Journal of Clinical Oncology. Ten years after trial cessation, 11 new primary melanomas had been identified in the daily sunscreen group, and 22 had been identified in the discretionary group. The overall difference was right at the edge of what could be chance, but the reduction in invasive melanomas, the kind that spread, was larger: 3 against 11. The trial’s background also notes that regular sunscreen use prevents cutaneous squamous cell carcinoma long term.

Is sunscreen absorbed into the body?

In 2019 the FDA ran its own trial. Forty-eight healthy adults applied one of four sunscreen products, lotions and sprays, to 75% of their body, once on the first day and four times a day on the next three days, far more than most people use. The researchers took 34 blood samples from each person over 21 days.

All six common chemical filters tested, including avobenzone and oxybenzone, got into the blood. Geometric mean maximum plasma concentrations of all 6 active ingredients were greater than 0.5 ng/mL, a level the FDA uses to decide whether a sunscreen ingredient needs further safety studies, and this happened after a single application. The most common side effect was a rash.

What the sunscreen absorption finding means

The absorption study measured blood levels, not health effects. Its authors stated directly that these findings do not indicate that individuals should refrain from the use of sunscreen. The threshold it crossed is a trigger for more testing, not a danger line.

The FDA has taken the same position. It notes that there is evidence that at least some sunscreen active ingredients are absorbed through the skin and enter the body, and that it needs to find out whether that exposure carries any safety risk. The FDA has requested data from industry to confirm the safety of sunscreen active ingredients.

What the FDA changed about sunscreen in 2026

The FDA’s review has led to changes. On September 10, 2026, FDA issued a final administrative order removing the active ingredients aminobenzoic acid (PABA) and trolamine salicylate from its list of permitted sunscreen ingredients, after finding their risks outweigh their benefits. Both are older ingredients that are rarely used today.

Earlier in the year it went the other way, adding a new filter, bemotrizinol, to the list. Mineral filters, zinc oxide and titanium dioxide, remain on the FDA’s list of permitted active ingredients and were not part of the absorption study.

What the sunscreen research cannot tell us

The Nambour trial is one trial, in one very sunny place, using 1990s sunscreen, with a small number of melanomas; its main melanoma result was borderline. Trials of this size and length are hard to repeat, which is why it remains the key evidence.

The absorption study was small, used deliberately heavy application and could not show whether the measured blood levels affect health. Long-term safety data for many chemical filters are still being gathered, which is what the FDA’s data requests are for.

What the sunscreen evidence adds up to

The trial evidence supports sunscreen as protection against skin cancer, including melanoma, and the absorption findings are a reason for more safety testing rather than evidence of harm. The FDA has removed two ingredients it judged unsafe and asked for more data on others.

The FDA’s own sun safety tips are to limit time in the sun, especially between the hours of 10 a.m. and 2 p.m., and to use broad spectrum sunscreen with an SPF of 15 or higher, reapplied at least every two hours, alongside clothing and shade.