If you are having issues with your adrenals, then caffeine intake needs to be limited based on the amount of trouble you are having with adrenal function. I have severe adrenal fatigue and was told not even decaf teas are allowed, and I slipped up once and found out why - WOW!
If you only have mild or no adrenal issues, then a small amount of caffeine or decaffeinated drinks are fine, and if you are using green tea for health reasons, this would be one time you would want to make an exception, if you don't have severe adrenal issues.
And a bonus if you have Babesia - green tea actually helps treat Babesia!
www.ncbi.nlm.nih.gov/pubmed/20025823