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Thyroid UK
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Ferritin/b12/iron confusion

Hi, I have been following advice from this site and have been supplementing D3 with co factors, b12, zinc & selenium. I feel much better and my muscle aches have disappeared so thanks everyone.

The only thing is, I’m still very pale. Looking at my ferritin results, it has increased from 18 to 25 in a year, whereas my b12 has gone from 287 to >1500!? (Dr told me stop the b12 now )

My question is how can I increase my ferritin if I can’t take any b12? I take ferrous fumerate daily. (14mg) Thankyou.

16 Replies

Eating liver raised my ferritin as I couldn't tolerate any iron tablets, however low the dose. You can have up to 200g liver per week.


Which type of liver did you use SeasideSusie ?


I use lamb's liver, I get it from my local butcher because I know it is Welsh lamb (I live in Wales).

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Thank you SeasideSusie, always good to hear people saying what worked well for them. Oddly enough I bought some lambs liver a few months ago from a butchers and it is still in the freezer, I cut some up into small pieces and was taking it daily to try and raise my vitamin B12 levels, unfortunately some of it got a bit stuck together and my plan to eat it three times daily failed. You have just reminded me it is still in my freezer :) :)

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B12 does not increase ferritin

How much ferrous fumerate are you taking. Do you take it with 1000mcg vitamin C to improve absorption

Having low stomach acid and/or malabsorption is most likely

Did you find out if you have high thyroid antibodies as replies suggested in previous posts

High antibodies means you have Hashimoto's also called autoimmune thyroid disease

Essential to know

What dose of Levo are you on and most recent TSH, FT4 and FT3 results

Low ferritin suggests malabsorption due to either inadequate Levo and/or gluten intolerance

Hashimoto's affects the gut and leads to low stomach acid and then low vitamin levels

Low vitamin levels affect Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

Ask GP for coeliac blood test first

Persistent low vitamins with supplements suggests coeliac disease or gluten intolerance


Have you been taking a good vitamin B complex for low folate?

If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before any blood tests, as biotin can falsely affect test results



Ask GP to test thyroid antibodies

Private tests are available


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after. This gives highest TSH, lowest FT4 and most consistent results

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The ferrous fumerate says it’s 14mg (125% RDA) and I take it with an effervescent vit c &zinc drink from Tesco. I’m on 125mcg levothyroxin. I’ll try and attach my last bloods.


SeasideSusie is the expert in ferritin

I suspect you need a different better quality vitamin C and ferrous fumerate two or three times per day. Vitamin C with each dose

Eating liver once a week can help too, if you like it.

Strictly gluten free diet likely to help too as it helps heal gut


Ok, thanks for replying, I’ll have a look.


So is that self sourced non-prescription ferrous fumarate?

FF on prescription is usually 210mg and each tablet contains approx 65mg elemental iron. You can also buy it from Amazon and some pharmacies.

If you want to take FF and have no problems with it then you will need the higher dose ones.

However, with a level of 25 with a range of 15-200 I would be speaking to your GP and ask for a full blood count and iron panel to see if you have iron deficiency anaemia.

I was recently offered a prescription for FF with a level of 39 because I was able to tell the nurse practitioner that my level had dropped from 119. I didn't accept the prescription due to the problem I have with taking iron.

How much Vit C is in your effervescent tablets? It should be at least 500mg, preferably 1000mg, to aid absorption of iron. And to be honest with the list of ingredients it contains I would run a mile from it


Citric Acid, Ascorbic Acid, Acidity Regulator (Sodium Hydrogen Carbonate), Bulking Agent (Sorbitol), Polyethylene Glycol, Maltodextrin, Sweeteners (Aspartame*, Acesulfame K), Zinc Oxide, Flavouring, Acacia Gum, Colours (Beetroot Red, Riboflavin), *CONTAINS A SOURCE OF PHENYLALANINE"

Why not buy some Vit C powder and add to orange juice eg amazon.co.uk/NutriBiotic-As...

454 X 1000mg servings in that pack and no added ingredients whatsoever.

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Because it’s in range, I hadn’t been offered it on prescription but I will certainly ask the doctor next time and look for the vitamin c. Thankyou again for your time.


You can buy your own ferrous fumarate 210mg in boxes of 84, which is enough for one tablet, 3 times a day, for 28 days (3 is the maximum dose per day - you may need only 1, twice a day).

This is a very common brand, but you may get a different one - the brand is not important :


It can only be bought from pharmacies (not on the shelves, you have to ask) or it can be bought online. Expect to pay about £5 per box, although it may be a cheaper. If one pharmacy won't supply it go to a different one. If you are asked why you want it just say your iron is low.

Ferrous fumarate 210mg contains 69mg pure iron per pill.

Take 1000mg Vitamin C with each pill.

Make sure that you leave a gap of 4 hours between taking thyroid meds and iron. Iron pills will reduce absorbency of your thyroid pills if taken too close together.

If you want a proper, thorough test of iron, you can get this finger-prick test done privately without involving your doctor. Before testing iron, stop taking iron supplements for 5 - 7 days.


Optimal levels for iron can be found here :


If you want assistance to go through iron results post them in a new post with the reference ranges and ask for feedback.

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Thankyou, I hadn’t thought if eBay. If I can’t get a prescription, I’ll get those. Thankyou for your time.


Yes your B12 has gone over range only because you have been supplementing - and so the results are skewed. No point in testing once supplementing and this is mentioned in Guidelines that are on the GP's desk which have not been read :-( So again another possible saving for the NHS !

The test for B12 is measuring both bound and unbound B12 circulating in the blood - but only 20% is available to be transferred to the cells where it is needed. So nothing can measure what is there. There is no need to stop B12 - you may find your results quickly plummet. If you decide to follow the advice of your GP I suggest you have it tested again in 3/6 months.


Thankyou, I will continue with B12 as I did feel better on it, thanks for your time.

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You cannot overdose as it is water soluble - so maybe every other day ?



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