Foggyme and others. Please could you confirm what is the correct dosage of ferrous fumarate and folic acid should be to ensure the optimum effect of the B12 injections? As posted previously, my ferritin was 7.5 ug/L [10.0 - 291.0] and my serum folate level was 10.85 ug/L [> 5.38] with the 5mg of folic acid which I take weekly. I know that you said that the ferritin should ideally be around 80ug/L and folate should be in the top third of the reference range, but I'm not sure how much iron and folic acid supplements to take to achieve this. Also, I've read in other posts that Vitamin D supplements should come with K2 supplements - is this correct? If so, how much for Vitamin D deficiency. I am going for a follow-up appointment to the GP on Wednesday, so all advice gratefully received, as ever! Thanks.