If you add T3 then as your FT4 is 81% through range then lowering your dose of Levo by 25mcg is suggested. A week or so later start with T3, 5mcg to start and increase by 5mcg at a time, 10-15mcg might be enough. I wouldn't go over to all T3 without trying combination first.
If NHS endo you won't get Thybon or Cytomel on NHS prescription. Thybon tends to be private prescription.
On a different note, I have always felt sluggish, even in my younger days.
I was putting that to laziness but I do know that my sister was and still an active person. My thinking is that perhaps it's because I was unlucky and I inherited the DIO2 gene mutation and she didn't. It's a theory and I don't have evidence that she hasn't inherited. But I do know that I have the DIO2 gene mutation.
So, my question is, this sluggishness (before I started taking Levothyroxine), is it related to the T4 to T3 conversion issue?
I can see FT4 is high but I don’t know whether those numbers show good/bad/reasonable conversion. I l’ve read on here that taking T3 will naturally lower FT4 and I want to understand under which circumstances a reduction in levo is advised
In this case is it because FT4 is high and adding T3 may lower/suppress TSH and that a too low TSH with high FT4 is a bad idea?
I don’t know whether those numbers show good/bad/reasonable conversion.
Besides looking at percentage through range for FT4 and FT3 - in this case 81% and 48.65% respectively - there is another way to look at conversion, we can divide FT4 by FT3 when the units of measurement are the same.
It's said that good conversion takes place when the ratio is 4:1 or less. In this case we have
FT4: 20.1
FT3: 4.9
so 20.1 / 4.9 = 4.1
So not dire but not particularly good.
I l’ve read on here that taking T3 will naturally lower FT4 and I want to understand under which circumstances a reduction in levo is advised
In this case is it because FT4 is high and adding T3 may lower/suppress TSH and that a too low TSH with high FT4 is a bad idea?
It's not usually suggested adding T3 until TSH is below 1 and then the suggestion to lower dose of Levo is generally based on how high the FT4 is. In this case TSH is below 1 so we know conversion is as good as it gets, and with FT4 at this level then lowering dose of Levo is probably right. 25mcg might be too much, 12.5mcg might be better, but it's all a case of experimenting and seeing what's right for the individual and, of course, this takes time and gradual tweaking of dose of each hormone to find whatever levels of each suit.
The OP might be one who is fine with a lowish in range FT4 as long as FT3 is in the upper part of it's range (getting FT3 into the upper part shouldn't be too much of a problem as it's not far below half way so I wouldn't expect a high dose of T3 is needed in this case), but they may also be like me and need both FT4 and FT3 over half way through range, only time will tell. As always, there's no one size fits all.
SeasideSusie thank you, I understand now but one more question: why isn’t that conversion rate a good one
It's said that good conversion takes place when the ratio is 4:1 or less. In this case we haveFT4: 20.1FT3: 4.9so 20.1 / 4.9 = 4.1So not dire but not particularly good.
SeasideSusie thank you, I understand now but one more question: why isn’t that conversion rate a good one
Because it's said that good conversion takes place when the ratio is less than 4:1 (some say 3.5 : 1).
In this case it's 4.1 : 1 so as I said it's not dire but not as good as it could be. Take into account that the OP has decent nutrient levels, high FT4 and middling FT3, DIO2 gene variant, high cholesterol plus symptoms then trialling T3 seems to be a sensible thing to do.
I think we have to remember that as ever nothing is set in stone, we are all different but the one thing we have in common here is that we have wonky thyroids for whatever reason. Individuality must come into it and what's right for one isn't necessarily right for another - the ratio of 4.1 : 1 might be perfect some one, others may need it lower, so we have to find what's right for us by experimenting with gradual changes.
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