Suncream may actually block the body's natural defence against harmful UV rays, a surprising new study has found.
Scientists from Brown University have discovered that human skin contains sensors that detect radiation from the sun.
These light receptors - which are also found in the retina of the eye - immediately prompt the release of melanin, the body's own form of sun protection.
This is likely to provide rapid protection against UV damage, long before the skin starts to tan.
Researchers now believe that full sunscreen blockage is not necessarily good in sun creams because they block certain wavelengths of light needed to trigger the body's natural defences.
Elena Oancea, lead researcher at the university in Providence, Rhode Island, said: “There was no prior evidence that those receptors can function in skin.”
“Our work shows that a dedicated UV receptor allows skin cells to immediately detect and respond to UV light.”
She added: “This protective capacity should be taken into consideration in the design and use of broad-spectrum sunscreens.”
