Glycerin is a thick colourless, odourless liquid which has been suggested to be a hyper hydrating agent (49). The main reason for this is that it can increase blood osmolality which augments the retention of water (50). It has been suggested to lower heart rate and prolong exercise (51), however research is still sparse on this ingredient further studies are needed in order to fully understand the capabilities of glycerin.
49 – WAGNER, D. (1999). Hyperhydrating with glycerol: implications for athletic performance. Journal of the American Dietetic Association, 99(2), 207-212.
50 – Robergs, R. A., & Griffin, S. E. (1998). Glycerol. Sports Medicine, 26(3), 145-167.
51 – Montner, P., Stark, D. M., Riedesel, M. L., Murata, G., Robergs, R., Timms, M., & Chick, T. W. (1996). Pre-exercise glycerol hydration improves cycling endurance time. International Journal of Sports Medicine, 17(01), 27-33.