The amount of kids and teenagers who use alternative supplements doubled between 2003 and 2014.
That's according to a new study in JAMA Pediatrics.
The most common supplements kids take are multivitamins and supplements for immunity.
Some children are taking Vitamin C, Omega-3 fatty acids and sleep aids, like melatonin.
Experts warn these alternative products can have serious side effects and may not be regulated by the FDA.