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Thyroid UK
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Query about ferritin and iron supplements

Dear all

Please can someone advise me on the following I have taken from my latest bloods (the same ones where my gp described a tsh of 14.63 as slightly raised)!

Serum ferritin - 31.2 (range 10 - 200)

Serum iron - 11.8 (range 11 - 30.00)

I'm guessing that although these are just within range that I should be supplementing?

Please can someon advise?

I am having folate and b12 tested next week because they forgot to request the this time!!!

Thank you in advance


9 Replies

Hi Lulu_65 I've just posted on your other thread suggesting those tests are done so well done on having them done already :)

Your ferritin is very low, it needs to be at least 70 for thyroid hormone to work, preferably 100+, and half way through range is best. You need an iron supplement. You can get Ferrous Fumarate or Ferrous Sulphate (Amazon, some pharmacies) and take 1 twice daily with 1000mg Vit C to aid absorption and help prevent constipation. Of you find that is harsh on your tummy or causes constipation you could try Iron Bisglycinate which is more gentle but more costly. Solgar Gentle Iron is one brand. Keep iron away from thyroid meds by four hours, and away from other supplements, as it affects absorption.

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Brilliant thanks again susie. I've got ferrous sulphate in my cupboard as have been anaemic on and off for years. I wasn't sure if ferritin and iron were the same or not ( lol!!!) I will start taking them straight away.

I will post my other results when I get them next week. I so appreciate your expertise.


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Personally I would avoid the sulphate and go for one of the others... I would expect you to be feeling quite tired with ferritin this low.

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Hi, why would you avoid ferrous sulphate? Is it due to tolerance? I never had a problem with it as been prescribed on and off for years. Or is it that the others are more effective?


If you've never had a prob with it, that's fine. It gives a lot of people constipation. Is all.

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Ferrous sulphate isn't considered to be as bioavailable as the other types of iron compounds, so while you would be taking in as much iron as if you took ferrous fumarate your body will absorb less.

This is one of the reasons the NHS has been prescribing ferrous fumarate instead. Ferrous sulphate use to be cheaper than ferrous fumarate about 3 years ago but they are now the same price.

If you been anaemic you know you can buy them off prescription from a pharmacy? Just use a pharmacy you don't get your thyroid meds from as you need to say to the pharmacist something like - "My doctor told me I am anaemic and to buy this." The pharmacist has to check why you need the supplements.

They cost about £3.75 off prescription.

Edit: Iron supplements give me either constipation or diahorrea regardless of type.


Gi there seaside Susie ☺ o know you are very knowledgeable and always help everyone heaps with your thorough advice. I want to very respectfully ask you why you say ferretin 100+? 70-90 is the range I use for women. As iron is an oxidiser and causes cellular damage. This is the range from functional / integrative medical practitioners. I just wondered if I have missed something regarding thyroid pts, or if our values need updating?

Hope you don't mind me asking.


Hi 108Optimist It depends on the range, we see a few different ranges on here, and apparently men should be higher in range than women.

It's always advised that for thyroid hormone to work ferritin needs to be 70, I've also seen quoted 80-90.

It's also frequently advised for ferritin to be half way through range, so that depends on what the range is.

My reply to Lulu_65 suggested at least 70 for thyroid hormone to work (as frequently advised) and 100+, I also said half way through range is best, which would be 105 with the range she quoted.

Obviously it's up to the individual to look into these things and make their own minds up (which I hope they do).

The practioner I consult told me that my ferritin level of 53 (20-150) was fine. I don't agree with her, 85 is half way through my range.

I also find that the 'figure of a minimum of 70 is needed' is confusing when the bottom end of the ranges differ. It would be helpful if there was a standard range for ferritin.

That's my take on it :)


Thank you Seaside Susie it's good to know how people get their heads around this ☺


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