Vitamin B12 supplements can be found in a range covering about 4 orders of magnitude. The RDA is 2.4 ug/day and the Costco daily multivitamin provides 6mcg, but

Vitamin B12 supplements can be found in a range covering about 4 orders of magnitude. The RDA is 2.4 ug/day and the Costco daily multivitamin provides 6mcg, but here is someone selling 10,000 ug supplements: https://www.hartzells.com/b-12-10000mcg-90960 https://www.hartzells.com/b-12-10000mcg-90960 It's easy to find any other order of magnitude between those if you like. A half-pound of beef liver would give you about 186 ug.