CRA considers that a dietary supplement is not zero-rated
Subject to a long list of exclusions, the ETA zero-rates “supplies of food or beverages for human consumption (including … ingredients to be mixed with or used in the preparation of such food or beverages).” CRA considers that dietary supplements which are consumed for their therapeutic or preventative effects do not so qualify, so that a liquid product along such lines which was to be mixed with water and ingested was not zero-rated.
Neal Armstrong. Summary of 29 March 2017 Ruling 183173 under ETA Sched. VI, Pt II, s. 1.