@ccchang I don’t know. It depends on your dietary habits if you have any gastric or male absorption issues. I inject the B12 and in between I might take the B complex supplement. I also take HEME iron to go with my Bs which seems to really help the nerves. Don’t take the iron all the time because it builds up. The Bs Cantu, so you should be monitored by a doctor. And then you can ask them the question. Before any supplementation if you really want to get your moneys worth, you should have your labs done otherwise you could possibly be wasting your money.