How long will it take T3 to work and how does it function?

[kendrewaddams]

My mum was recently prescribed T3. 5mcg, 3 times a day, along 175mcg Levo that she already takes.

I know the question is sort of impossible to answer, but how long will it take to see whether it's having a positive effect or not? Can anyone with experience shed some light?

Also, since T3 is very short acting, and wearing off after 5 hours, how does it function? Does it slowly build up in the system?

[SlowDragon Administrator]

It can take many months to tweak dose levothyroxine and T3

How long has she been taking?

Bloods should be retested 6-8 weeks after any dose change or brand change in levothyroxine or T3

What’s the timing of each 5mcg dose T3

All four vitamins need to be optimal too

See from previous posts you are working on these

Has she seen any improvement at all?

Which brand of levothyroxine is she currently taking

Are you making sure she gets same brand at each prescription

[greygoose]

So she was started on 15 mcg T3 straight off? That's a very high starter dose. Might make her feel worse before she feels better.

Normally, we say to start on 5 mcg T3 and increase by 5 every two weeks.

Also, since T3 is very short acting, and wearing off after 5 hours, how does it function? Does it slowly build up in the system?

Who told you that? That's rubbish. The half-life of T3 in the blood is about 24 hours. But, it doesn't do anything in the blood. It has to get into the cells to actually do anything - and that can take a while - but once it's in the cells, it stays there for about 3 days. And, all the time, you're taking more doses, so there's always some in the blood, trying to get into the cells, and some in the cells working it's magic.

Does it build up in the system? To a certain extent, yes. Not like T4, but it does a little.

[radd]

kendrewaddams,

Based on your Mums previous test result she had elevated thyroid antibodies, high CRP inflammation, elevated cortisol, low Vit D, iron that needed improving, and over-range FT4 level on 200mcg Levo.

All these factors could make the acceptance of T3 difficult, and the reduction of only 25mcg T4 with the addition of 15mcg T3 will make her further over-medicated. If your Mum feels shaky, has a racy heartbeat or anxiety you should stop the T3 & leave off for a few days.

Too high levels of thyroid hormones can be counterproductive as only work best when the right amount & ratio is hit upon. As your Mum was over-medicated on 200mcg Levo, and if she is wishing to medicate 15mcg T3, then Levo should be reduced to 125mcg, giving a total of about 170mcgT4.

To avoid too bumpier ride for your Mum start with a 5mcg or even 2.5mcg dose of T3 for a week or two before raising very slowly. Many members experience an inner heat and/or headache for a few days when first introducing T3. This is usual but anything more means the dose should be reduced and held for longer.

It may be that although she is hoping T3 may help with her symptoms, this may not happen until some of the above issues are addressed.

[kendrewaddams in reply to radd]

Thanks for the reply! The current course she is on was prescribed by <redacted doctor name>, who was recommended on the preferred Thyroid UK Drs list. The only thing he brought up with me was her Vitamin D, which has now been resolved with supplementation.

[helvella Administrator Thyroid UK in reply to kendrewaddams]

The doctor's name has been edited out in order to conform to guidelines:

28. Do not post information about specific endocrinologists or doctors on the main board without their permission as this may result in unwanted attention from certain areas of the medical profession. If you wish to discuss a particular endocrinologist or doctor, you may mention his/her name and location, providing that you ask for comments by private message only.