But you have to take very high doses before you'll see any positive effects. Researchers have been testing the healing powers of the vitamin at levels of between 50,000 and 200,000 IUs—and the recommended daily allowance is just 400 IUs.
People given the highest doses were seeing skin inflammation reduce dramatically after just 48 hours, and they also had less skin redness, say researchers at the Case Western Reserve University.
The vitamin triggers activity in the genes that helps repair skin damage, and those with the highest blood levels of the vitamin seemed to have the greatest protection as well as the fastest healing.
This suggests that people who have gradually increased their exposure to the sun could have the greatest natural protection against burning.
"Vitamin D helps promote protective barriers in the skin by rapidly reducing inflammation. What we did not expect was that at a certain dose, vitamin D not only was capable of suppressing inflammation, it was also activating skin repair," said researcher Kurt Lu.
The researchers tested various levels of vitamin D on a group of 20 volunteers, who had been put under a UV lamp until their arm was red. After an hour, they were given varying doses of the vitamin, ranging from 50,000 to 200,000 IUs, and were checked every day for three days to see if the skin was healing.
The research team is next going to test high-dose vitamin therapy on burn patients.