What dose of Levothyroxine with T3?

What dose of Levothyroxine with T3?

I'm going to start taking T3 hopefully in the next few days when it arrives. I was diagnosed hypothyroid 16 years ago and I've been on different doses of Levo since. I've been recommended to take T3 with Levo. However, I'm wondering if I should drop my current dose of Levo from 75mcg to 50mcg and then start off with 5mcg of T3 or stick with the 75mcg? How would you work this out? I'm getting very anxious just thinking about it in case something goes wrong. I'd appreciate any advice. Thanks.

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8 Replies

  • Serendipitious You need your current FT4 and FT3 results from the same blood draw to see where your levels lie which can guide you how to dose.

  • SeasideSusie The most recent results I have unfortunately don't contain Free T3 as they are from my GP:

    January 2017 (75mcg)

    TSH 2.86mIU/L (0.34 - 5.6)

    Free T4 11.70 pmol/L (7.5 - 21.1)

    November 2016 (75mcg)

    TSH 1.75 mU/L (0.27 - 4.2)

    Free T4 17.4 pmol/L (12 - 22)

    Free T3 2.7 (L) pmol/L (3.1 - 6.8)

    I'll add a photo of the Genova Thyroid 24 Hour Urine test I did in December 2016 but this was when I took a few capsules of Adrenavive iii and reduced Levo to 50mcg for a few days.

    Dr P said I should drop Levo to 50mcg but Prof C said there's no need so I'm very confused now.

  • Serendipitious,

    You are under medicated on Levothyroxine (T4) so you shouldn't reduce dose when you add T3. I would start with a quarter tablet (6.25mcg) taken with your T4. If you don't have any adverse symptoms you can increase dose and take a second 6.25mcg dose at bedtime. I would stick with 12.5mcg T3 for 8 weeks and order a private thyroid test including FT3 before increasing further.

  • Free T3 is a must when using T3.

    On your current results I wouldn't reduce your levo as your FT4 is rather low in it's range. Add a quarter of a tablet of T3 which will be 5mcg or 6.25mcg depending on brand, most self source T3 is 25mcg tablets. See how you go and add another quarter after 2-3 weeks if you feel you need to.

  • Does T3 decrease TSH? Is T4 only raised by Levothyroxine? Will adding T3 affect Free T4?

  • My understanding is T3 can lower TSH and it may also lower FT4. As Levo is T4 then taking Levo will raise FT4. T3 can't raise T4 (if that was behind your question :) ).

  • Yes it was about whether T3 can increase Free T4. I was trying to understand what the criteria was for lowering Levo. I used to be on 100mcg and was on that dose for a few years but my current GP took the liberty of reducing it to 75mcg around March 2016 and since then my health has become a lot worse. I never feel well and I'm frequently anxious and stressed especially when facing a change 😩.

  • Serendipitious T4 (our own or Levo when we are taking it) has to be converted to T3 which is the active hormone that all our cells need.

    T3 cannot convert to T4.

    If you take synthetic T3 then normally you don't need so much T4 (or Levo).

    T3 is approx 4 times as 'potent' as T4. So 25mcg T3 roughly equals 100mcg Levo, or 6.25mcg T3 roughly equals 25mcg Levo.

    So if you had high in range FT4, say 21 (12-22) then adding 6.25mcg synthetic T3 is like adding an extra 25mcg Levo and you would be over medicated on that. So in this example you would try reducing your Levo by 25mcg if you added 6.25mcg T3.

    In your case your FT4 is very low in range 11.70 (7.5-21.1) there's no need to reduce your Levo when adding T3.

    Of course, that's a generalisation and we have to see what happens and tweak Levo and T3 until we find a combination that suits us as individuals.

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