A zinc oxide powder is described, which, when used in a dispersion at a concentration of at least 50 wt% of zinc oxide, produces a transparent composition having a total visible transmittance through a path length of 20 microns at 550nm of at least one of at least 70%, at least 75%, at least 80% or at least 85%. The powder has a number average zinc oxide aggregate size of at least 0.8 microns, at least 1 micron, at least 2 microns or at least 3 microns. Use of the zinc oxide powder reduces the risk of transdermal penetration.
