I have read on here and other sites thyroid hormone needs a ferritin of around 70 to work properly however I have also seen people say it needs to mid range. The range given with my bloods is 15-250 so does this mean I need to be aiming for 120ish rather than 70?
Thanks!
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liaratsoni
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Iron deficiency is shown to significantly reduce T4 to T3 conversion, increase reverse T3 levels, and block the thermogenic (metabolism boosting) properties of thyroid hormone (238-242). Thus, iron deficiency, as indicated by an iron saturation below 25 or a ferritin below 70, will result in diminished intracellular T3 levels. Additionally, T4 should not be considered adequate thyroid replacement if iron deficiency is present.
However, a ferritin level below 70 does not confirm iron deficiency. I have quoted that to show that conversion of T4 to T3 will likely be impaired if ferritin is below 70, hence why you see it quoted on this forum that ferritin needs to be 70 for thyroid hormone to work properly.
I have read in one article that females who brought their ferritin level above 100 saw their persistent hypothyroid symptoms relieved, and another article suggests that a level of 100-130 is good for females
I always use the rule of thumb that we should be aiming for a level of ferritin which is 50% of the way through the range. It should be a safe level for just about everyone, male or female, pre- or post-menopausal, and it caters for different ranges too.
Having said that, some people might still need a level which is a bit higher (but still in range) if they have restless legs or similar problems which won't go away. (There are other possible causes for cramp, twitching, restless legs other than iron, but low iron is one of the commonest causes.)
And pre-menopausal women might need higher levels of ferritin too - see this paper :
It is important to realise that people shouldn't supplement iron solely on the basis of a low ferritin level - various problems can arise if done inappropriately :
The statement that ferritin needs to be around 70 'for thyroid hormone to work' is nonsense. Most of the world's population has ferritin levels well below 70 and no problem getting their thyroid hormone to work. If thyroid hormone didn't work your TSH would be astronomic as the hormone could not suppress the pituitary.
The 70 figure came from a study finanaced by a cosmetics company that markets 'iron shampoo' and related to hair quality, nothing to do with thyroid.
I notice that you have central hypothyroidism? TSH stimulates deiodinase (T4 to T3) conversion so if your TSH is lower than expected you may need some T3 medication.
Hypothyroidism can lead to low ferritin levels so if hypothyroidism is corrected you may see ferritiin rising at the same time.
I was on 75mcg t4 and 10mcg t3 and was feeling very bad so was upped to 15mcg t3 but got very unwell - after over a week of bad dizziness and anxiety I ended up with frequent periods of high heart rate and other horrible symptoms so had to reduce. Then I found couldn't even tolerate the 10mcg T3 anymore so currently I am on 5mcg and just about deal with that. Last blood tests showed Free T4: 13.8 (10-20)
and Free T3: 4.9 (3.5-6.5) taken after coming back on to 75mcg t4 and 10mcg t3. I also had a Vit D deficiency again and ferritin was 23 (15-250) with a haematocrit of 0.36 (0.37-47) so endo prescribed iron tablets. This last few weeks I have had a lot of anemic symptoms with awful lightheadedness every time I stand up and try to move around, shortness of breath etc. I did have a ferrtin of 89 - highest its been in my life and with no supplements or iron rich food - back in february when my t3 and t4 were 70% through range each and I was closest to recovered I have been. I assume ferritin has dropped as they dropped. I am hesitant to take iron tabs after reading about differences in iron and ferritin. I also currently have terrible anxiety, crushing tiredness in the morning and a higher than normal for me heart rate. I am planning to get bloods done end of this week because I wonder if lack of T4 is a problem here.
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