In tests on mice, scientists placed a microneedle patch infused with a mix of minoxidil and steviosides on the rodents' bald back every day for a month and found it triggered new hair growth across 67.5 percent of their back by the experiment's end. Mice who had the standard two percent minoxidil solution, without steviosides, sprayed onto their backs every day for the same period saw regrowth over just 25 percent of the bald area.