The active ingredients of commonly used sunscreens end up in the bloodstream at much higher levels than current U.S. guidelines from health regulators and warrant further safety studies, according to a small study conducted by U.S. Food and Drug Administration researchers and published on Monday.
The over-the-counter products originally marketed to prevent sunburn with little regulation are widely used to block radiation from the sun that can cause skin cancer, the most common malignancy in the United States.
The study of 23 volunteers tested four sunscreens, including sprays, lotion and cream, applied to 75 percent of the body four times a day over four days, with blood tests to determine the maximum levels of certain chemicals absorbed into the bloodstream conducted over seven days.