1 cc a day for 7-10 days. The reason is you want to get your liver filled with it then it should hold what it needs and product more as it needs it.
Once a week should do nothing at all, so I am not sure if you are doing any good at all needleboy. The info I have comes from a Dr. friend of mine that gets me some b-12 here and there to make sure my body is stocked on it.....