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Thyroid UK
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Blood test

Would it be ok to take my Levothyroxine at 10 o'clock at night and get my blood test done round 11 o'clock next day as I take it in the morning but would like to try it at bedtime and take my T3 in day time and off course I would take it after my blood test is done , I am still working out my correct dosage as I can't take the levo and T3 close or I feel so ill and wouldn't like to miss my dosage at the moment ,

7 Replies

It is recommended to have approx 24hours between last dose of levo and blood test so you should miss 10 p.m dose and you can take it after your blood test and can continue with this dose on the same day at the same time as usual. You can take T3 anytime during the day as long as you haven't eaten for about 2 hours or 2.5 hours if it has been a fatty meal and allow about 1 hour after T3 before you eat. Food can interfere with the uptake.


I dint know you had to wait as long with food when taking the T3 as someone put on here that you can take near food unlike the levo that you have to wait regarding food


Maybe they wont get the full benefit of the hormones that they would have. An excerpt:-

By taking T3 with meals, a patient reduces the amount of T3 that will enter her blood. Some food constituents, such as calcium, bind thyroid hormone in the GI tract. This effectively limits the amount of T3 that absorbs into the blood, the rise of the blood T3 level, and the brief exposure of the heart to higher concentrations of T3. But there is a problem with this approach.

The patient who takes T3 (or T4) with meals won’t have anywhere near an accurate idea of how much T3 enters her blood. Different meals will contain different amounts of T3-binding substances that will reduce the amount of T3 that enters the blood. One meal may contain a small amount of T3-binding substances; another may contain a large amount. As a result, the amount of T3 that enters the blood after meals is likely to vary a lot. Accordingly, the degree to which T3 drives the patient’s metabolism any day is also likely to vary widely.


Taking T3 with meals, then, blurs the relationship a patient and her doctor may look for between her dose of T3 and her metabolic status. The proper solution is simply to reduce the amount of T3 the patient takes on an empty stomach. With this approach, the relationship between a particular dose of T3 and metabolic status will be far clearer.

1 like

Thanks so much for info as will try this as not feeling at all well


I am using Perrigo T3 ,a and wonder if anyone else has tried this brand ,


Sometimes it takes us a while to find a dose or combination which makes us feel much better so don't be too worried at present. Unfortunately it's not a quick fix that some doctors believe. For the patients who are feeling unwell, every day is too long.


I saw a consultant endo at Hull last August. He told me that I should have left at least 24 hours without any thyroid meds before having a blood test. I'd left it only 16 hours and was told this was not enough time to get the meds out of my system. Apparently that is what they are looking for with the blood results.

Prior to this, I'd always been told not to take meds on day of blood test.


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