T3 and iron supplements : Dear all, I’d be very... - Thyroid UK

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T3 and iron supplements


Dear all,

I’d be very grateful for some advice. I take T3 first thing in the morning and then at about 6pm (on an empty stomach). I saw my rheumy yesterday (I have Sjögrens/lupus overlap) and told her that my legs are really achy...they have been for ages. She said that this was sometimes caused by lack of iron (my blood tests always show anaemia)...so I am hopeful. However, somewhere in my very scatty memory, I remember reading thAt you shouldn’t take iron and T3 as it stops absorption. Can anyone advise? Also, which iron to take. Floradix?

Thank you in advance.

6 Replies

You are right re not taking iron/ferritin anywhere near any thyroid hormones whether T4 or T3 as it ‘wraps’ round the hormone( and any other drug and supplement too). If possible leave at least 2 if not 4 hours from iron. I found it difficult to take two doses of T4/T3 combo and T3 along with food, and folate, ferritin, b12 ( and B Complex, and vit D( tho now take this with K2 in drop form) so take my thyroid hormones in middle of the night now. I take iron tablets (Ferrous fumerate ‘Pure Nature’) with vit C daily, and alternate other supplements like magnesium ( another problem one) every other day. Has your GPs not given you iron, or checked why you have problems/ anaemia?

Thank you. My gp just flicks through blood tests and says ‘you’re anaemic’...and then says...so what can I do for you today!?! Not much help, but he does prescribe what my Endocrinologist and rheumatologist say. So I take T3 for hashis and Hydroxychloroquine for Sjögrens/lupus. I’m also on a clinical trial with biologics just now, and when I saw my rheumy yesterday and complained of aching, painful legs she said it can be a symptom of anaemia. It makes sense, so I thought I’d try some..but had remembered reading about not taking T3 and iron near each other. I will ensure 4 hours apart. Thank you!

Ok, sometimes think we would get along reasonably health wise if it wasn’t for doctors and pharmacists just supplied our needs! Good luck


Iron must be taken at least 4 hours away from any thyroid meds as it affects their absorption. Taking Vit C with iron aids it's absorption.

As for which iron to take, if you have been diagnosed with anaemia, it's up to your doctor to prescribe something and monitor you.

What are your latest tests - iron panel and full blood count?

Thank you. I will take with vitamin c...4 hours away from T3.


For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also extremely important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially with Hashimoto's. Essential to regularly retest vitamins.

What vitamin supplements do you currently take ?

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw). This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

If/when also on T3, make sure to take last dose 8-12 hours prior to test

Is this how you do your tests?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins


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 special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

As you have Hashimoto's are you on strictly gluten free diet?

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. Dairy is second most common.

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

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Ideally ask GP for coeliac blood test first or buy test online for under £20, just to rule it out first

Trying gluten free diet for 3-6 months. If no noticeable improvement then reintroduce gluten and see if symptoms get worse







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