How long to see results from adding T3 to T4

So how long should it actually take to feel/see a difference when adding T3 to the T4? I started on T3 9 days ago. I am currently taking .137 Synthroid and 5mcg of T3 twice daily. I feel some what better, however, not experiencing the 'feel better' I thought I would. Have much more stamina since having my Synthorid upped in July to the .137. I can really tell that difference. Endo won't retest me until March! So if I read correctly from previous posts my TSH will rise? When I had it tested this last time it was at .525 and my T3 was at the bottom of the range. Just curious how this all works. Since if I am correct, I am taking the equivalent to .167 Synthroid?

10 Replies

  • Guysgrams, 10mcg T3 is equivalent to 30mcg Levothyroxine. It will take 4-6 weeks to feel the full impact of the 10mcg and as FT3 was bottom of range you may need an increase to 20mcg in a few weeks. Ideally levels are retested 6-8 weeks after a dose adjustment. I found symptoms lagged about 7 weeks behind good FT3 levels.


    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • Thanks, I know I should be tested in about 8 weeks but this endo stretches everything to at least 3 sometimes 4 months. :(

  • T3... Take it in the morning and you should feel a bit better by lunchtime. Its an active hormone, it doesn't store so really you should feel better straight away.

    10 mg is a teen teeny dose.... When i first took it, some 13 years ago, with no internet or doctor help, i reduced my t4 by 50 mg and started t3, once a day at 25.

    Thyroid meds dont speed you up noticibly or give some sort of epiphany.... All that happens, is that you feel normal. That's it... Just normal. If crap things happen you still feel rubbish and if you have a late night, you still feel tired....

    but normal, is just that.... You suddenly realise that you stayed awake all day, after a proper nights sleep.

    Xx g

  • Thanks, just wish I really knew what normal for me was. It has been a very long time. I will be thrilled when I can actually stay awake until 10 o'clock P.M. :)

  • In September I saw a consultant who prescribed T3 (20 daily divided into 2 doses - 10 at 7am and 10 at 1pm) as well as 100 thyroxine. Until then I had been on 100 thyroxine only. With the added T3 I didn't feel good so reduced my thyroxine to 75. My hair has started to really thin and fall out and especially at the front I can see my shiny scalp. Could it be that I need to reduce the thyroxine further down to 50. I had a blood test with the new endo last month and he said my results were very good. Any ideas on what I should do next as I don't see the endo again until January and by that time I wont have much hair left.

  • What level is your ferritin and how are you for zinc?

    Xx g

  • Ferritin 241.8 (range20 - 150) high result

    CRP 0.50 (normal <3.0)

    B12 - 497 (range 142 - 725)

    Serum folate 25.75 (range 10.4 - 42.4)

    Free T4 - 14.1 (range 12-22)

    TSH 0.08 (range 0.27 - 4.2)

    Free T3 - 5.3 (range 3.1 - 6.8)

    Don't know about zinc

  • Just replying as I also have started supplementing my thyroxine with T3, it has been 12 days now and I am definitely noticing changes albeit very subtle. It is hard to describe but daily chores have not required a supreme effort just to do them and are in fact getting done instead of being put off until tomorrow. These are teeny tiny things but I do feel less brain fogged and less worn out. I really hope it continues and even my husband has noticed that I seem less phased by how to get something done. I am pretty sure it is the T3 working, less dormouse in the teapot and probably a bit more mad hatter!


  • Yep, that sounds like its working.... :-)

  • Me too very subtle changes. I was noticing that yesterday when I was at the shopping mall. I thought to myself "I would've been worn out" afterwards four months ago!

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