My B12 levels were 198pg/ml so I started supplementing with 5000mcg daily. Next test showed levels had risen to 2000pg/ml so I cut back to 5000mcg once a week. Next test showed levels at 799pg/ml, which I understand is about right, so I continued at the same dose.
3 months later I notice that the aches and pains which had definitely improved, are now back with a vengeance, so it looks as though my levels are sliding downwards again.
How do you work out what is an adequate maintenance dose without getting tested every month? GP won't test again.