According to a new study, sunlight continues to damage people’s skin and increase the risk of cancer for hours after exposure.

Scientists at Yale University discovered it was the supposedly protective pigment melanin that was causing the damage.

The research team says the findings may lead to better sunscreens that can prevent the extra damage.

When UV radiation pummels our skin cells, it can cause mutations in the DNA.

Melanin, the pigment behind a tan or natural skin tone, is the body’s defense as it absorbs the radiation.

What scientists did not know previously was what happens to all the energy that the melanin has absorbed.

The Yale team showed, in the journal Science, that the high-energy version of melanin supercharges a series of chemical reactions.

A cocktail of superoxides and peroxynitrites culminate in a “very high-energy molecule breaking apart and releasing the energy that was holding it together”, said lead researcher Prof. Douglas Brash.

In laboratory tests, the whole damage in skin was still taking place four hours after UV exposure was stopped.

“Half or more of this kind of DNA damage is not happening on the beach, it’s on the car on the way home,” Prof. Douglas Brash said.

The team hopes they can develop a sunscreen that combines the usual protection with absorbing any energy from the melanin.