Thyroid UK
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Test Results

Hi, on 1st October I had some blood tests done and the results were as follows:

TSH 0.26 (0.4-5.5)

Free T4 18.3 (11.0-26.0)

Free T3 3.8 (3.0-6.0)

Ferritin 15 (10-291)

My GP was happy with my thyroid results although personally I think I would feel better if my free T3 was higher. She put me on ferrous fumarate for four weeks and my ferritin levels were tested again last week along with B12 and folate. She didn't test for vitamin D. My results were:

Ferritin 39 (10-291)

B12 616 (190-910)

Folate 13.9 (4.6-20.0)

I have seen a very slight improvement but I feel a long way from my usual self. MY GP expected more of an improvement even though she agreed the ferritin was at the lower end of normal. She's prescribed another month of ferrous fumarate and has said if I don't feel better after that she'll refer me to an end to make sure she hasn't missed anything with my thyroid. I've been taking a good compound B vitamin but could I benefit from B12 lozenges? I know my level isn't that bad but I've read optimal is around 800. I have no idea about folate levels so I don't know if they're below optimum or not. Any thoughts/recommendations would be appreciated.


2 Replies

Julie, take each tablet of ferrous fumarate with 500mg-1,000mg vitamin C to aid absorption and mitigate constipation. Ferritin is optimal at 70-90 so you'll probably need at least 4 months supplementing to improve that much. FF is available OTC if your GP stops prescribing.

Absorption of Levothyroxine and FT3 should improve when your ferritin is higher. Make sure to take Levothyroxine 4 hours away from ferrous fumarate.

B12 looks ok but it won't harm you if you supplement 500mcg-1,000mcg methylcobalamin sublingual lozenges, spray or patches. Folate looks fine.

Most of us need to supplement 2,000iu vitD3 daily Oct-Apr when ultraviolet levels are too low to stimulate vitD. Good levels of vitD also aid conversion of T4 to T3.


Thanks. I've been taking the vitamin C with the ferrous fumarate and will continue with both even if my doctor stops prescribing it. I'll try the B12 and D. I was taking vitamin D until I ran out recently but I'm pretty sure the dose wasn't as high as that so I'll make sure to take enough. Hopefully if I can get my ferritin level up my FT3 will improve as well. Thanks again.


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