Thyroid UK
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T3 please advise me? Meaning of results + what next?

Please could you tell me more about T3 especially this:  if I reduce my dose of Levothyroxine, will T3 go up or down?   My thinking is that if my body fails to convert synthetic T4 to T3 then lowering the dose might mean my body produces more natural thyroxine.  Or could it be the other way round, that my body needs an even higher dose of Levo because little is converted?  

(I'm on 75 mcg of Levo weekdays, 50 mcg at weekends).

Latest results Feb 2016 are:

T4 18.3 (range 10 - 24.5)

T3 3.9 (range 3.8 - 6.7), "normal"

TSH 0.07 "slightly suppressed". (Range I think is 0.05 - 5 or 7)

Ferritin 15 (range 12 - 300)

(now taking prescribed Ferrous Fumarate) and

Ferritin has risen to 34.

In December 2015:

B12 = 438 (range 180 - 1000), being vegan I supplement though stopped before the test

Vitamin D 50.9 (range over 30-40)

Folate 20+ (range 4+)

Calcium 2.26 ("good")

Inflammation "none"

History is that I became hypothyroid between the ages of 12 and 15 though unrecognised until I was about 45, once diagnosed GP easily traced it back from symptoms.

My results go up and down more than I can show for lack of test results, but if you would please look at Jan 2014 to June 15 you'll see what happens, and I don't feel much different on Levothyroxine. Still suffer from weakness, fatigue (diagnosed as CFS but I don't think so), low mood, low energy, always cold, very poor memory and general brain function and more of the usual symptoms though oddly the reverse of constipation even while taking prescribed iron.

Previous results though I'm sorry I only have 'normal' sometimes and no ranges, I didn't know the value of figures until coming onto this site.


"TFT down to 6.8" guess this means TSH

Before 2011

"TFT 7.3" I guess this meant TSH

Feb 2011

"TFT 9.1" - LATER told "TFT 1.9" so I guess this meant TSH 1.9

B12 "high"

April 2011

"TFT 1.5"

D3 at bottom of range

Nov/Dec 2011

TFTs all "normal" (on Levo)

B12 868

Jan/Feb 2014

T4 21.1 (range 10 - 24.5 I presume)

TSH less than 0.05

GP recommended pregesterone, which does seem to help.

October 2014 (apparently the GP wrote in my notes she though I was not taking the Levo!)

TSH 15.9

June 2015

TSH 1.0

August 2015

TSH 2.7

Thank-you for sharing your knowledge and experience.

7 Replies

Your body needs T3 because you just aren't converting. Lowering your T4 would not make your gland produce mord hormone. If it were capable of doing that, you wouldn't need to take the Levo. In order for you to convert enough T4 to T3, you would need to take a very, very high dose. And that just isn't a good idea. You need T3. IMHO

1 like

Many thanks Greygoose, now can you tell me please how you know I am not converting because my GP says the results are fine.


Because your FT4 is up over mid-range, and your FT3 is scrapping along the bottom. 

If you were converting correctly, your FT3 would be higher than your FT4 in their respective ranges.

If your doctor thinks your results are 'fine', with an FT3 like that, then he is spectacularly ignorant! You are very hypo, but I expect he is only looking at the TSH, and possibly a glace at the FT4, but has no idea what the FT3 indicates. He doesn't know that it is low FT3 that makes you hypo, not a high THS. High TSH is the result, not the cause.


You are never going to feel well until you get that FT3 level Up.

You would need to take a very high dose of levo which could make you feel awful.

You really need to start adding in some T3.

1 like

I had a similar set of results to you on 75mcg levo, and felt pretty rubbish.  GP at the time wanted me to reduce my dose because of TSH, I tried it and felt even worse.  So they referred me to an endo, and I went onto 20mcg of T3 only, which wasn't enough. Then I added in 25mcg levo and felt a lot better, but still some room for improvement.  My endo now actually wants me to reduce the levo to every other day because my TSH is slightly low, but I'm currently resisting as I know it'll make me feel worse and I'm only just about ok!

Anyway, in all that waffle, what I'm saying is that you may well benefit from some T3 with your levo - I wouldn't necessarily recommend a wholesale change to T3 only though without trying a combination, as in my experience it's a bit of a rocky road.

1 like

Many thanks Mountaingoat83, how did you get referred to an endo, my GP says that my results are fine so there's no need for a referral.  Is your endo anywhere near Gloucestershire?


I wasn't having any periods and told my GP I wanted a baby, so that got things moving.  No I'm in south yorkshire, but to be honest I wouldn't recommend my endo as it's been pretty hard work.  

Perhaps you could present your GP with some of the evidence showing that people feel better when their FT3 is higher in range?


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