Thyroid UK

ferritin dropping but b12 over range

hi everyone,

last year my ferritin level dropped to 5 and was put on ferrous sulphate 200mg 3 times daily, was on 50mcg levo (and still am) but my b12 was 1100plus. managed to get my ferritin up to 49 but coudn't tolerate the iron (have IBS as well) so GP advised stop iron and see what happens. Ferritin dropped steadily since then by ten points each three month blood test and now back down to 14 (tested last week) but surgery won't give iron as I am within normal range. blood last last time (3 months ago) showed tsh 0.84 and I felt fine but last 3-4 weeks sleeping all tme again with severe chest pains and breathing probs.

TSH gone up to 2.19 last week also, so guess I need more thyroxine now, but my b12 continues to be over 1000, should I be worried about this? I don't take b12 supplements, only adcal d3 in terms of vitamins.

7 Replies

I have just re-read your post and realise you've been on 50mcg since last year. This is a starting dose and it should have been increased around 6 weeks later and so on until you felt well. Usually 50mcg of levo is increased after 6 weeks and thereafter an increase until you feel well. Some GPs think once we reach a 'normal' level their job's done. It's not we need to feel healthy with no clinical symptoms.

Re B12 - Our body takes up whatever B12 it needs and excess is excreted. I note you don't take B12 supplements so someone may have another viewpoint.

This is a link re too low a dose of levo. Go down to the date June 8, 2001



I started at 25mcg and it was increased to 50. was borderline hypo when first started but cos I had high antibody levels GP started me on 25 and increased it to 50 when my TSH started to rise again even though still within range.

bit worried about the B12 though a I know high levels if you aren't taking suplements, can be indications of nasties like hepatitis and leukemia and there is a strong incidence of cancer in the family (lost both parents, aunt and cousin all in last few years to it and many other relatives in past)


Someone who is more knowledgeable than me will respond but this is an excerpt I have just read:

B12 Dangers

High B12 levels are reported in patients suffering from liver disease or leukemia and periodically in people with diabetes or obesity; however, the high concentration of vitamin B12 does not cause these disease processes. There are no adverse affects from taking high doses vitamin B12. Vitamin B12 is a water-soluble substance; therefore, the body will take what it needs and excrete the rest in the urine, according to the University of Michigan Health System and Guillermo Arroyave Ph.D.

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thanks for that, but I think I am worried because I am having consistently high levels of B12 WITHOUT taking supplements, I think that the quote above is mainly to reassure people taking supplements that there is little or no risk in overdosing as B12 won't CAUSE the diseases mentioned. Thank you anyway, though, I appreciate the time and effort you took to look it out for me :)


Ask your GP to be referred to a haematologist who will be able to reassure you. It is obviously worrying you.


Saw the GP today, He put me back back on ferrous sulphate (600mg daily) to get my ferritin back up and said even though it is within range it is only just in range and it may well be below my optimum range to be well and levo increased to 75mcg as symptoms back and tsh rising even though still within range. My GP is so lovely!

Spoke to him about b12 being so high, he reassured me that I had no markers for hepatitis and if I had it I would be feeling much worse than I am now, also blood tests showed all white blood cell levels okay which they would not be if I had anything like leukemia. Was checked for diabetes recently and that is fine too so all's well :)

He is going to do another liver test in three months to make sure and said he would keep an eye on the levels in future tests.

Thanks so much for your hepl--feeling reasssured now! :)


I am glad you have a good and caring doctor and hope with your rise in thyroid hormones you will soon be so much better.

I am glad he was reassuring about the high b12.


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