CRG -- I bought the B12 from AR-R and run 1000mg EW. Also bought their LiquiDex. It's a sublinqual (put it under your tongue). They recommended dosing is .25mg ED. I started taking it when I bumped my test dose up from 200mg EW to 400mg EW. By the end of two weeks my dick didn't work and I felt a bit crappy. I stopped taking it this week because it seems I tanked my E2 levels. I'll resume taking it if I get symptoms of my E2 going too high. Everyone aromatizes test at a different rate and you may not need an AI at all with the dose of test you're taking. It's good to have an AI on hand, though. If I go back to using it I'm only going to take it every 3rd day.