It is not the matcha itself that has been highlighted as potentially causing liver damage - it is the ECGC (Epigallocatechin Gallate) content. The European Food and Safety Authority provided an opinion on ECGC which warns that a dose of 800mg/day or above can lead to initial signs of liver damage. The matcha powder we use typically contains 2-3% EGCG (20-30mg per 2 capsule serving) and thus is well under the threshold for concern.