Sceletium:
Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in
Cognitively Healthy Subjects: Implications for Alzheimer's Dementia. - Evid Based Complement Alternat Med. 2014;2014:682014. doi: 10.1155/2014/682014. Epub 2014 Oct
19. Chiu S, Gericke N, Farina-Woodbury M, Badmaev V, Raheb H, Terpstra K, Antongiorgi J, Bureau Y, Cernovsky Z, Hou J, Sanchez V, Williams M, Copen J, Husni M, Goble L.
A toxicological safety assessment of a standardized extract of Sceletium tortuosum (Zembrin®) in rats. - Food Chem Toxicol. 2014 Dec;74:190-9. doi:
10.1016/j.fct.2014.09.017. Epub 2014 Oct 6. Murbach TS1, Hirka G2, Szakonyiné IP2, Gericke N3, Endres JR4.