Image from APiS UK Propolis is a resin-like compound honeybees collect to coat their hives. New research suggests that this compound may increase hair growth as observed in studies of mice. Although the researchers did not test propolis on balding mice, they did find faster hair growth in mice that had been shaved or waxed, which is somewhat promising. Source: Miyata S, Oda Y, Matsuo C, et al. Stimulatory Effect of Brazilian Propolis on Hair Growth through Proliferation of Keratinocytes in Mice.J. Agric. Food Chem. 2014.