The claim: Sunscreens can increase the risk of melanoma, which in its malignant form is deadly skin cancer.
The facts: Is it possible that a product meant to protect against skin cancer might actually cause it?
Several studies have investigated claims that zinc oxide and other compounds in some sunscreens might have harmful effects.
Some laboratory studies show that zinc oxide and titanium oxide – compounds that block ultraviolet rays – can also create free radicals in the presence of sunlight, leading to cell damage.
Others point to research showing a general rise in melanoma cases over the years, particularly in people who use sunscreen
However, for these compounds to cause harm, they must penetrate skin cells and research by health officials in Australia, which has one of the highest rates of skin cancer in the world, found that this does not happen.
"The weight of current evidence is that they remain on the surface of the skin and in the outer dead layer (stratum corneum) of the skin,” one report said.
In other studies researchers followed thousands of people, looking for connections between melanoma and sunscreen. They found no evidence of greater risk.
They also noted that people who sunbathe often or have greater sun sensitivity are more likely to use sunscreen possible explaining the associations in earlier studies.
The bottom line: Studies suggest zinc oxide and other compounds in sunscreen do not damage cells or increase melanoma risk.
- The New York Times