Could low ferritin be causing headache or is it a reaction to NDT?

3months ago my GP prescribed iron after I showed her my private blood test which had my ferritin was below range at 7.

2months ago I switched to NDT (Thai Thiroyd) from Levothyroxine 100mcg (but undermedicated). I am now up to 2 grains.

I had suffered from regular headaches, extremely heavy periods, fatigue etc all of which started to improve and I hadn't had a headache for over 2 months until this week and I've had this one for 2 days now and feel too tired to do anything.

My iron ran out about 2weeks ago & my GP has not yet renewed my prescription so I'm taking some I bought but it isn't nearly as strong. Question is am I reacting to lack of iron or the NDT?

I wonder if anyone else has had experience of this?

18 Replies

  • Headaches are a classic symptom of low iron, ask your gp for another ferritin test to see if you have managed to get it up into the 80s. Bet you haven't.

  • Yes I shall although it wasn't my go that did the test despite the fact I had gone with lots of symptoms. I suspect that's why she hasn't given me the repeat prescription I asked for.

  • What type and dosage of iron supplement were you prescribed? All iron supplements prescribed by doctors on the NHS can be bought in pharmacies if you know what to ask for and where to ask for it.

    If you don't hang on to iron very well your low iron symptoms can return very quickly if you stop supplementing before getting your levels up to optimal - and even then levels can drop like a stone if you are unlucky.

  • It was ferrous sulphate 200mg twice a day but I haven't found that dose anywhere. If I don't get a new prescription I'll try a pharmacy .

  • I bought ferrous sulphate 200mg a few days ago from Boots. I had to ask for it from behind the counter and was quizzed as to why I needed it.

  • Try Lloyds or Tesco pharmacies - you will have to ask. I get my ferrous fumarate from there. I first started taking it with a prescription, but now I don't bother I just get it myself.

    I ask for ferrous fumarate 210mg, in a box of 84, which is enough for 28 days when taking 1 tablet, three times a day which is the maximum dose.

    For info on what doctors prescribe, see this link :

  • Do you know the difference between fumarate and sulphate?

  • They are different iron salts which are both prescribed by the NHS for the purposes of fixing iron deficiency. Sulphate is grim stuff that is the cheapest iron supplement the NHS prescribes. Fumarate is also a bit of a problem with regard to tolerance, but is slightly better tolerated than sulphate by most people - there are some exceptions who prefer sulphate to fumarate. There is little difference with regard to iron content.

  • Is there anything other than Sulphate & Fumarate? what is the best type of iron to take - I haven't been able to glean much from my online research yet?

  • The best type of iron to take is the one that you can tolerate which also raises your iron levels. There isn't one that works for everyone, sorry.

    That link I gave you earlier mentions ferrous gluconate. I've never tried it. It has much less iron in than sulphate and fumarate, but if people can't tolerate anything else then they just have to do the best they can.

  • Remember to leave a good gap between thyroid hormones and iron. This is an excerpt:

    Iron supplements (FEOSOL, SLOW FE) have been shown to reduce the effect of levothyroxine in some people, although the effect is highly variable from one person to another. Other iron preparations may also have similar effects. Again, we advise taking the levothyroxine four to six hours before or after the iron.

    Also within the link is 'other' things which can affect the uptake.

  • Oh yes I had forgotten that (so many things to remember regarding timing), but it doesn't mention NDT I wonder if it is also true for that or just the synthetic T4 meds?

  • I believe it refers to all thyroid hormones, whether T3, T4, NDT.

  • Will iron infusions stop Levo working?

  • You would have to ask an Endocrinologist/haematologist and hopefully he'd know. They should also be monitoring your blood levels I think for thyroid hormones.

  • I hope you're feeling better. I too switched from 100 levo to ndt , taking 2.5 grains. I suffer extremely heavy periods which haven't really improved and i have always got bad headaches that can last a couple of days near my period which I think could be a dip in my iron levels- they aren't great. I also get the occasional heart palpitation too. Or I wonder if it's hormonal , I doubt it's the Ndt.

  • If you've switched to NDT, you increase every two weeks till you have relief of symptoms. I think 1/4 at a time is sufficient. Slow and gradual is always best.

  • So I started taking iron supplements again a couple of days ago and upped the dose (though not to 200mg because I'm using a liquid form that has other vitamins in & I'd have to overdose to get to 200) but today the headache has gone and I'm feeling more alert. The Surgery rang and asked me to come & see the doctor because I'd need more blood tests for another prescription. I'll make sure I'm off the iron for 5 days before too.

    @Sidtrivett I would suggest getting your Ferritin checked because you sound exactly like me. I always thought my headaches were hormonal because they would happen every month around my period - but this past 2 months for the first time in about 20yrs I've had a light/normal period and no headaches (until this one when I'd stopped the iron) - that is enough evidence for me that it was the likely cause.

    Just think how much pain and suffering I could have avoided not too mention the numerous ibuprofen I took! I had been tested for anaemia several times and was always told I wasn't but I never saw the results and don't know if that included ferritin. I've also been vegetarian for 30yrs.

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