It is only more potent in the sense that as a prodrug of Tenofovir, just like the existing Viread(TDF), TAF converts to Tenofovir mainly in the liver cells, therefore has less
side effects. But as Stef2011 stated, they reduced the dosage of TAF accordingly, so the same amount of Tenofovir is delivered to the liver cells as TDF. It would be really nice if they can do a proper dosage study of TAF/TDF specifically for HBV (and not use the same dosage for HIV/AIDS).