Not sure whether there is any research looking into this but until recently I have been using Teavigo Green Tea Extract 90% EGCG, 30 Veg Capsules by Swanson but these have been out of stock. I have started taking a different preparation (which has higher EGCG): https://www.british-supplements.net/products/clean-green-tea-extract-polyphenols-916mg-catechins-748mg-egcg-420mg
But I wondered whether there was anything particular about the TeaVigo preparation that made it better for accessing the brain?
Best wishes all,