Thyroid UK
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Vitamins and minerals

Given my symptoms should I be on more dose of my prescription supplements please? As well as thyroid medication I have been taking 1 200mg ferrous fumarate tablet since 2013, vitamin D3 800iu since 2013 and 5mg folic acid since November last year.

Ferritin 19 (15 - 150)

Folate 2.31 (2.5 - 19.5)

Vitamin B12 208 (190 - 900)

Total 25 OH vitamin D 44.2 (>75 adequate)

Symptoms are things like not concentrating very well, hard stools, heavy periods, dry skin, pins and needles, breathlessness, headaches, fatigue, muscle cramps, muscle twitching and joint pain. Feedback is appreciated. Thank you in advance.

6 Replies

Hi Amber995

I'm no expert, certainly not in the medical field, so this is only my personal opinion.

I would suggest you post on the HU PAS forum with your above results as you will be able to get some more experienced help there. Click on 'My Communities' at the top of this page to find the PAS forum

In the meantime, I would say that your B12 levels is low, although within range; Folate is low, and often is associated with low B12; Ferritin is quite low in the range, in spite of you taking iron supplement; Vit D is also too low, best to be higher than 75-80.

So, I feel you need to do some research yourself and talk to your GP. Hopefully, he will either do further tests or maybe start treating your low B12 but, unfortunately, GPs seem to feel treatment is not necessary at this level - a rather mistaken GP :(

Please don't self-treat until you/GP have exhausted all investigations, otherwise any investigations will be skewed and make diagnosis very difficult.

Good luck. Hope you feel better soon

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Ferritin 19 (15 - 150) - taking 1 x ferrous fumarate since 2013. The reason that your ferritin is abominably low even after taking an iron supplement for 4 years is because you have not been prescribed enough. The usual dose for low ferritin is 2 x daily. However, have you been taking your iron tablet with 1000mg Vit C to aid absorption (it helps prevent constipation too). In case you don't know you should take iron 4 hours away from thyroid meds and two hours away from other medication and supplements.

If not already done, I would ask your GP to do a full iron panel, full blood count and haemoglobin to see if you have anaemia.

From the Patient Information Leaflet for ferrous fumarate:

"The usual dose to treat Iron deficiency anaemia is one tablet two to three times a day.

The dose for prevention of anaemia is one tablet once or twice a day.


Your doctor will advise you on how long you should take the tablets.


*You should not take the tablets for more than six months.* "

Check the Patient Information Leaflet in your box, it should say the same. Point this out to your GP and emphasise that it should not be taken for more than six months and see what he says.

Ferritin needs to be at least 70 for thyroid hormone to work properly, recommended is half way through it's range and for females best is 100-130.


Folate 2.31 (2.5 - 19.5) - taking 5mg folic acid

Vitamin B12 208 (190 - 900)

Your folate is under range and B12 very low. Pop over to the Pernicious Anaemia Society forum here on Health Unlocked and see what they advise.

Folate is recommended to be at least half way through it's range, and B12 at the very top of it's range, even 900-1000.


Total 25 OH vitamin D 44.2 (>75 adequate) - taking 800iu D3 since 2013. The reason your Vit D level is still inadequate four years after commencing supplementation is because 800iu is a maintenance dose for someone with an already reasonable​ level, it won't raise a low level. The recommended level is 100-150nmol/L.

Just buy some 5000iu softgels like these and take 5000iu daily for 3 months then retest. When you've reached the recommended level you can reduce the dose to 5000iu alternate days, maybe less in the summer. Retest once or twice a year to keep within the recommended range. Private fingerprick blood spot tests can be done with City Assays for £28.

When taking D3 there are important cofactors needed -

D3 aids absorption of calcium from food and K2-MK7 directs the calcium to bones and teeth where it is needed and away from arteries and soft tissues where it can get deposited and cause problems. D3 and K2 are fat soluble so should be taken with the fattiest meal of the day, D3 four hours away from thyroid meds.

Magnesium comes in different forms, check to see which would suit you best and as it's calming it's best taken in the evening, four hours away from thyroid meds

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Thanks for reply, I have found vitamin C tablets make my stomach heavy when I took them with iron so I stopped taking the vitamin C tablets. Iron has been on and off my repeat prescription for all this time.


Amber995 Have you tried a different form of Vit C? Was it the ascorbic acid form you used? There are other, more gentle forms. Look for sodium ascorbate or calcium ascorbate. There are powdered forms which might be better than tablets as there are no fillers. Iron will be much better absorbed with Vit C.

Also, start eating liver once a week, I did that to raise my ferritin as I couldn't tolerate iron supplements, and still eat it now to maintain my level.

Once your level reaches the correct level (mentioned above) then maintaining it is vital. Stopping the supplement altogether and your level will plummet, requiring supplementation to bring it back up again. Yo-yoing like that is no good for us. Get the level up and maintain it either with a low dose of a gentle iron supplement or, the very best way, eat liver regularly.

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Thanks it was ascorbic acid from Holland and Barrett, fizzy tablets. I dissolved them in water then crushed the iron tablet into the mixture before drinking it in one go.


Well, H&B own brand supplements are best avoided as they contain plenty of rubbish that can cause reactions.

If you get a powder then there are no additional ingredients and you can just dissolve in a little orange juice (or your preference) and it makes a pleasant little drink.

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