"This is the peer reviewed version of the following article: Chen X, Chen X, Brauer DS, et al. Sodium is not essential for high bioactivity of glasses. Int J Appl Glass Sci. 2017;00:1-10. 10.1111/ijag.12323 which has been published in final form at https://doi.org/10.1111/ijag.12323 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."