. 2014 Dec 24;9:241–272. doi: 10.2147/DDDT.S71106
© 2015 Zhang et al. This work is published by Dove Medical Press Limited, and licensed under Creative Commons Attribution – Non Commercial (unported, v3.0) License
The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.
Figure 1.
Chemical structures of caffeine and melatonin.