Blue light has been shown to trigger discoloration in the skin in those with skin types that have a tendency to tan. Studies have shown that the likelihood of triggering discoloration in the skin is higher in those with skin types III or higher. These skin types tend to tan easier than they burn. There is some evidence that blue light may trigger the development of free radicals in the skin. The concern is that these free radicals can damage the DNA of cells. If this occurs the potential for premature aging of the skin can occur.
Broad spectrum sunblocks and products containing niacinamide have been shown to prevent this type of discoloration. Some studies have shown a benefit to products that use iron oxide as an active ingredient to protect against blue light.
Broad spectrum sunscreens containing Zinc or Titanium are reasonable. These can block the ability of blue light to reach the skin and trigger any damage or increase in pigmentation.