London – Scientists have developed a drug that mimics sunlight to make the skin tan, with no damaging UV radiation involved.
The drug tricks the skin into producing the brown form of the pigment melanin in tests on skin samples and mice.
Evidence suggests it will work even on redheads, who normally just burn in the sun.
The team at Massachusetts General Hospital hope their discovery could prevent skin cancer and even slow the appearance of ageing.
UV light makes the skin tan by causing damage.
This kicks off a chain of chemical reactions in the skin that ultimately leads to dark melanin – the body’s natural sunblock – being made.
The drug is rubbed into the skin to skip the damage and kick-start the process of making melanin.
Dr David Fisher, one of the researchers, told the BBC News website: “It has a potent darkening effect.
“Under the microscope it’s the real melanin, it really is activating the production of pigment in a UV-independent fashion.”
It is a markedly different approach to fake tan, which “paints” the skin without the protection from melanin, sun beds, which expose the skin to UV light or pills that claim to boost melanin production but still need UV light.
But the team is not motivated by making a new cosmetic.
Dr Fisher said the lack of progress in skin cancer – the most common type of cancer – was a “very significant frustration”.
He added: “Our real goal is a novel strategy for protecting skin from UV radiation and cancer.
Tests, detailed in the journal Cell Reports, have shown the melanin produced by the drug was able to block harmful UV rays.