I might be late to the game on this, but apparently green tea extract, specifically EGCG has been linked to liver damage. Granted, it’s only a correlation, not necessarily causation. I took 1g per day for 3 months during my competition shred. My blood work ALT and AST were normal during this time, but I’m not going to take chances with it next time.
I only found out this week because of a Lifehacker article.