... Fourteen studies compared a zinc-containing product to other available treatments for acne vulgaris (Bojar, Eady, Jones, Cunliffe, & Holland, 1994;Chu, Huber, & Plott, 1997;Cunliffe, Burke, Dodman, & Gould, 1979;Cunliffe et al., 2005;Dreno et al., 2001;Feucht, Allen, Chalker, & Smith, 1980;Habbema, Koopmans, Menke, Doornweerd, & De Boulle, 1989;Langner, Sheehan-Dare, & Layton, 2007;Micha€ elsson, 1980;Micha€ elsson, Juhlin, & Ljunghall, 1977;Papageorgiou & Chu, 2000;Schachner, Pestana, & Kittles, 1990;Sharquie, Noaimi, & Al-Salih, 2008) (Table 3), out of which only four were controlled (Feucht et al., 1980;Micha€ elsson, 1980;Papageorgiou & Chu, 2000). Ten studies compared a zinc-containing compound to an antibiotic. ...