Resvera-Flo is the only natural grape-source resveratrol and ellagic acid supplement available. All other resveratrol is from the root of Japanese knotweed. Resvera-Flo is made from purple muscadine berry and wild, raw northern American grape. This is the original muscadine berry/grape concentrate, complete with all of the powerful flavonoids extracted from the skin. Resvera-Flo provides 2 mg of highly rare ellagic acid and 132 micrograms of resveratrol per serving.