T3 only therapy after total thyroidectomy?

[Gardenofeden]

I apoligize if this question was asked already but after a total thyroidectomy, one MUST take BOTH t4 and t3 meds correct?...not just t3 only?

Many thx☺

[cjrsquared]

No not true. After my TT I was put on liothyronine only before having radio active iodine 3 months later. The oncologist explained that t3 was the active hormone and if you have sufficient your body didn't require t4 to convert to t3. Many people on this forum do well with t3 only, others a combination of t4 and t3, either synthetic or as NDT and yet others on t4 only. The problem is finding the optimum replacement for you as what works for one may not suit another.

There are a lot of knowledgeable people on this forum, I'm sure if you pose other questions members will be able to help you on your journey. Goodluck.

[Clutter]

Gardenofeden,

No. I was prescribed Liothyronine (T3) inbetween thyroidectomy and RAI because T3 has a shorter half life than Levothyroxine and I would only need to be off T3 for 2 weeks prior to RAI. I was switched to Levothyroxine after RAI.

[Gardenofeden in reply to Clutter]

Oh yes!

Prior to radioactive iodine i can totally understand but what i meant was for lifelong treatment after the total thyroidectomy.

Sorry i should have been more clear😕

[Gardenofeden]

I just thought that because a normal healthy human thyroid gland produces mainly t4, that after a TT you *must* take a replacement of T4...and some t3 if need be.

Thx

[helvella Administrator Thyroid UK]

It isn't clear to me why a total thyroidectomy would require a different approach to T4/T3 combinations than, for example, someone born without a thyroid, or another person who has virtually no detectable thyroid tissue due to autoimmune disease.

The need for T4 has long been an important but unclear area. The usual theory seems to be that T4 has no effect of its own but only when converted into T3. This has been questioned, for example:

Thyroxine and tri-iodothyronine differently affect uncoupling protein-1 content and antioxidant enzyme activities in rat interscapular brown adipose tissue.

Full text available by following link on this page:

ncbi.nlm.nih.gov/pubmed/125...

I am amazed how well some people seem to be on T3-only. Entirely support anyone who finds T3-only works for them, but am always concerned that it might not be the optimum.

[Hypomom]

I have read many articles which state that the CNS only has receptors for t4 to convert to t3.

The brain and spinal cord do not accept direct t3, it must be in the form of t4 originally, as there are no direct t3 receptors only t4 receptors.