Thyroid UK
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Latest bloods: Free T3 okay?

Latest batch of bloods done on Monday, results back lightening fast:

TSH: 0.12 (0.35-5.5)

FT4: 15.9 (10-19.8)

FT3: 4.1 (3.5-5.5)

As I now take my T3 at bedtime (taking it in the morning with my bupropion made my feel slightly hyper, I'd not taken any for approximately 36 hours before the draw. Am I to conclude that the FT3 level is fine?

Before taking bupropion I was taking my T3 in the morning and the bloodwork suggested that I could stand to take a bit more. Would there be any merit in taking 10mcg at bedtime, rather than 5mcg? Do I still get any benefit from taking it at night rather than during the day?

6 Replies

Your blood tests look good but the most important question is 'How do you Feel'. That is the guideline we should aim for.

Before the blood tests and levo was introduced we were given NDT upon clinical symptoms and increased until they went and we felt well.

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If you feel you need more T3, it is less than half way up the range, so you could stand a bit more. No point if it makes you feel worse.


hose, it's sufficient to leave 24 hours between thyroid meds and blood draw. You have a false low FT3 measurement by leaving 36 hours. There's probably more benefit in taking T3 at night as it will mimic natural circadian rhythms where T3 is highest around 2-3am.


The trouble is, if you take your T3 at night and the blood draw is in the morning then you either leave 12 or 36 hours between dose and blood. False high or false low...


hose, T3 is out of your serum after six hours so 12 hours is plenty. You can take the T3 a few hours earlier if you have a crack of dawn blood draw.

If you take T4 at night too, I would leave 36 hours.


Magic. Cheers, Clutter.


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