I've been taking Bluebonnet liquid methylcobalamin, 5000 mcg (2 doses a day) for quite awhile and did well with it, though it's a little pricey - $24 for a month's supply. A few months ago I found "Why Not Natural B12" on Amazon, 5000 mcg. liquid methlcobalamin (https://smile.amazon.com/Sublingual...04804062&sr=8-1&keywords=why not natural b-12) and it seems just as good as the Bluebonnet product, but is $20 instead of $24. The Why Not Natural 12 is in an alcohol base, unlike Bluebonnet, but I don't mind. FWIW, I did MB12 shots for quite awhile (3 x a week) several years ago with no noticeable effect, though I'm sure they did something., And then tried sublingual B12 and that did not seem to do anything either. It was when I went to the liquid form, 2 x a day (once was not enough), that I finally felt a bit of extra energy.