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Suppose you’re one of the millions who heed the advice of dermatologists to protect your skin from cancer-causing UV rays. You dutifully spritz and slather on products whenever you venture outdoors.

And then you catch a glimpse of a report saying the ingredients in sunscreen could actually cause cancer. Suddenly, you’re wary of a product you thought was protecting you.

It’s a good idea to research claims and pay attention to the science behind products you use on your body and in your home. Here’s what the research says about the cancer risks of using sunscreen.

Spoiler: The cancer risk from not wearing sunscreen far exceeds any potential health risk from sunscreen ingredients.

There is no scientific evidence that using sunscreen causes cancer. Both the American Academy of Dermatology and the Canadian Dermatology Association recommend that people use sunscreens to protect themselves from exposure to UV rays, which cause 80-90 percent of skin cancers.

Two different kinds of sunscreen

The active ingredients in chemical sunscreens absorb UV rays so they don’t damage your skin. The active ingredients in physical sunscreens block UV rays.

Chemical ingredients seep into your skin and enter your bloodstream, but physical sunscreen ingredients don’t penetrate beyond the outer layer of your skin.

One of the reasons consumer advocates have raised concerns about chemical sunscreens is that the active ingredients can be found in blood, urine, and breast milk after a single use. That means the active ingredients are absorbed through your skin and throughout your body.

In 2019 and 2020, the Food and Drug Administration published two reports asking for more data on the effects of six chemical sunscreen ingredients commonly sold in the U.S.:

  • avobenzone
  • oxybenzone
  • octocrylene
  • homosalate
  • octisalate
  • octinoxate
  • ensulisole

All six of the chemicals were found in the bloodstream in concentrations much higher than the FDA recommends.

The FDA has also asked for more data on several sunscreen ingredients that are not usually sold in the U.S.:

  • cinoxate
  • dioxybenzone
  • meradimate
  • padimate O
  • sulisobenzone

Although the FDA asked for more data, the reports did not suggest that using sunscreens with these ingredients was dangerous. But because the studies show absorption into the body, the FDA wants more information about the effects the ingredients may have, if any.

Using sunscreen has several important health benefits.

Sunburn protection

If you apply the right amount of sunscreen with an SPF of 30 or higher, reapply it often, and don’t stay out in the sun too long, it should protect your skin from burning. Cream or lotion sunscreens typically offer more sunburn protection than sprays.

SPF Explained

The American Academy of Dermatology recommends using a sunscreen with an SPF of 30 or more if you’re going to be exposed to the sun.

A sunscreen with a high SPF will wear off in the same amount of times as a sunscreen with a lower SPF, so you’ll still need to reapply sunscreen often.

Aim for reapplication every two hours — more often if you’re swimming or sweating away your protection.

Here’s a complete guide to sunscreen use.

Skin cancer protection

The most important benefit of sunscreens is that they protect you from UV rays that can cause skin cancer. Skin cancers are the most common cancers in the U.S. Around 9,500 people are diagnosed with some form of skin cancer every day in the U.S., and two people die of skin cancer every single hour in this country.

Protection from skin damage

Health experts estimate that around 80 percent of facial aging comes from being exposed to the sun’s UV rays. The sun can cause dark spots, wrinkles, loss of firmness, sagging, and roughness over time. A broad-spectrum sunscreen can protect your skin from sun damage and accelerated aging.

Although there isn’t any evidence that sunscreens cause cancer, some studies have shown potential problems with certain ingredients in various sunscreen products.

Hormone disruption

Oxybenzone, one of the ingredients in the spotlight of the FDA reports, is classified as an endocrine-disrupting chemical. It has been shown to affect hormone levels in animal studies, but the evidence of hormone disruption in humans is conflicting. Some studies indicate that oxybenzone is associated with lower testosterone levels in young men, but there is no evidence that the testosterone drop is enough to affect male fertility.

It’s important to point out that sunscreen isn’t the only product that contains oxybenzone. It’s found in cosmetics and personal grooming products, too.

Kidney injury

At least one study measured the amount of processed oxybenzone in human urine samples. Researchers found that higher concentrations of oxybenzone were present in the urine of people who showed signs of kidney damage.

Birth weight changes

There is conflicting evidence that oxybenzone could contribute to a higher birth weight for some babies. Some studies show a higher birth weight in male babies whose mothers used oxybenzone products while they were pregnant. Other studies show no association between birth weight and oxybenzone use.

Allergic reaction

Some sunscreen ingredients cause allergic reactions. Common skin reactions include:

  • redness
  • hives
  • pain
  • rash or bumps
  • peeling
  • bleeding
  • puffiness or swelling

These ingredients are most often linked to allergic skin reactions:

  • oxybenzone
  • benzophenones
  • cinnamates
  • dibenzoylmethanes

Fragrances can also cause skin irritations or allergies.

Toxicity to coral reefs and marine ecosystems

Oxybenzone and octinoxate have recently been banned in Hawaii and Key West, Florida because they may harm marine life, including coral reefs. A 2020 research review said there wasn’t enough evidence to determine whether these two chemicals cause any harm in humans.

A word of caution: A 2019 study found that only 52 percent of sunscreens labeled “reef safe” are actually free of ingredients known to be toxic to marine life.

The way skin cancers look can vary according to the type of cancer: squamous cell, basal cell, or melanoma. You should get regular skin checks with a dermatologist, and be on the lookout for symptoms such as:

  • red patches that itch or bleed
  • crusty sores
  • shiny bumps
  • growths with raised borders and dents in the middle
  • wart-like growths that bleed or form crusts
  • any growth with an irregular or jagged border
  • asymmetrical moles or growths
  • moles or growths that contain varied colors
  • moles or growths that are changing
  • moles that grow larger than 6 millimeters

Follow the ABCDE rules for mole checks

CDC’s Division of Cancer Prevention and Control recommends that you do a monthly mole check to look for any suspicious, new, or different-looking moles.

Here are the ABCDE’s of mole checks to help you remember:

  • A for asymmetry. Is the mole or spot irregular in shape or have two parts that look very different from each other?
  • B for border. Is the border neat and clean or is it jagged or irregular?
  • C for color. Is the color uniform or is it blotchy or uneven?
  • D for diameter. Is the mole larger than a pea?
  • E for evolving. Is the mole changing in any way?

If you notice changes or have concerns, speak with your doctor or a dermatologist immediately.

Sunscreens manufactured and sold in the U.S. are regulated by the FDA. While the FDA doesn’t usually test individual products, they do require manufacturers to use ingredients that are safe for human use, and they require products to list their ingredients on the label. The label will also identify where the product was made. Sunscreens made outside the U.S. may contain ingredients the FDA has not approved or has banned.

If you’re concerned about the possible health effects of chemical ingredients that make their way into other body systems, you may feel safer using a physical (mineral) sunscreen with ingredients like titanium dioxide and zinc oxide.

Something to consider if you choose mineral sunscreens is nanoparticles. In the past, mineral sunscreens that contain zinc and titanium dioxide were thick and pasty. Newer formulations are made with nanoparticles, so they feel better on your skin. Manufacturers claim they block out more of the harmful UV rays, too.

While there have not been concerns about cancer risks to date, some health professionals have raised concerns because nanoparticles, which can damage your lungs if you breathe them in large enough amounts. For that reason, the Environmental Working Group warns against using powder or spray sunscreens that contain nanoparticles. Cream or lotion sunscreens containing nanoparticles are absorbed through the skin, but there isn’t any evidence so far that nanoparticles harm your health.

Nanotechnology in sunscreens is relatively new. For that reason, it’s hard to know how nanoparticles will affect your body. It’s also hard to predict the effects these sunscreens will have on ecosystems. More research is needed so researchers, manufacturers, regulators, and consumers understand what these particles mean for people and for marine life.

Some ingredients in sunscreens can be absorbed through your skin, which has raised concerns about the possibility of cancer risk. However, there is no evidence that any of the ingredients in sunscreen raise your risk of cancer.

Dermatologists in the U.S. and Canada recommend that you wear a sunscreen with an SPF of 30 or more when you’re in the sun. Sunscreen protects your skin from the harmful effects of the sun’s UV rays, one of which is skin cancer.