Dear all, it seems to me, herbal methionine (better to call it "herbal extract") can replace only methylation part of methionine-betaine methylation cycle. It is possible to do via activation enzymes taking part in both methylation cycle and folate cycle (it is connected to methionine cycle), using a key metabolite tetrahydrofolate (THF). So it's clear why herbal extract doesn't contain methionine ...