Advice on taking T3 and Levo before a blood test - Thyroid UK

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Advice on taking T3 and Levo before a blood test

pamelashep profile image

Hi can anyone give me advice on what time to take my T3 and Levo before a blood test.

Since adding T3 to my Levo my TSH has dropped to 0.02 and my dr is not over happy about this, so she is testing me every two months to see if there is any change with the TSH.

I have been stopping the T3 and Levo for 5 to 7 days before my blood hoping to keep the TSH around the 0.02 mark as any lower and she will stop the Levo.

I feel well on 100mcg of Levo and half a tablet of Cynomel T3 which is 12.5

Has anyone any ideas. Thanks

11 Replies

And yet another ignorant doctor! Did she prescribe the T3? If so, she should know that when you take T3 your TSH drops to practically nothing. That's what happens. And, it happens for a reason: because you no longer have any need of TSH. It serves no useful purpose when you are taking T3.

pamelashep profile image
pamelashep in reply to greygoose

No she didn't prescribe the T3 that's the problem and she accepts reluctantly that I'm taking it and that it lowers the T3 but keeps calling me for a blood test. So just wondered if you had any advice on the time a take it before a blood test.

Thanks for replying grey goose, most kind

greygoose profile image
greygoose in reply to pamelashep

Normally one leaves 8 to 12 hours between the last dose of T3 and the blood draw. But, that is to make sure that the FT3 result reflects the normal circulating level of T3. But, it won't have any effect on the TSH.

The TSH rises slowly, and is unpredictable. There's not even any guarantee that it will rise even if you stop T3 completely. What you are doing is dangerous. And, your doctor is ignorant. The two together are lethal. You're not helping your progress by keep stopping the T3 to allow the TSH to rise. Your body has become used to having it, And will suffer without it. And you're not helping educate your doctor by doing so. She has got to learn that the TSH is not important, and she should not be dosing by it. It's an impossible situation. I don't know what to tell you, sorry.

pamelashep profile image
pamelashep in reply to greygoose

Yes I agree, it's impossible. She says she understands the T3 but by taking the T3 I have stopped the natural process by taking the T3. But I felt rubbish before hence the T3 which was prescribed by a dr, but as she put it not by her.

We are told repeatedly to take responsibility for our health and when we do, it's wrong isn't it. Thanks Pam

greygoose profile image
greygoose in reply to pamelashep

What 'natural process'? You have hypothyroidism, there aren't any 'natural processes' anymore. Presumably you started T3 because you didn't convert very well, so what 'natural process' is she talking about? I don't think she knows anything about thyroid. And, you could argue that taking levo is stopping a 'natural process'. I think she's just making it up as she goes along to hide her ignorance.

SlowDragon profile image

If you are stopping Levothyroxine and T3 you're

A) getting inaccurate test results

B) may be actually making a TSH go lower

When we mess about with dose TSH can get confused and drop even lower

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

If/when also on T3, make sure to take last 5mcg dose 8-12 hours prior to test, even if this means adjusting time or splitting of dose day before test

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

When were vitamin levels last tested

What vitamin supplements do you currently take?

About a year ago, with Blue horizon. Think most things were fine then will have to find my copy of the test and come back to you. But thanks for replying. Pam

Ah didn't realise that. Thought it might come up a bit. The TSH I mean by stopping it for a few days before the test, as that's the issue. Low TSH. Although it's the T3 causing it. Pam

SlowDragon profile image
SlowDragonAdministrator in reply to pamelashep

In theory stopping replacement thyroid hormones should cause TSH to rise

In practice it just seems to cause terrible upset, lower vitamins and upset cortisol levels

You might find if you left it several weeks TSH might rise.....but likely to become very unwell and not necessarily rise TSH hardly at all

Interesting. Maybe that's why I feel bad when I do it then. It certainly takes longer to pick up level wise than it does to drop down. Didn't realise it would interfere with the cortisol. Thanks for advice

SlowDragon profile image

Previous Vitamin test results here

Vitamin D likely too low

GP will only prescribe to bring vitamin D up to 50nmol. Aiming to improve by self supplementing to at least 80nmol and around 100nmol may be better .

Once you Improve level, very likely you will need on going maintenance dose to keep it there.

Retesting twice yearly via

Vitamin D mouth spray by Better You is good as avoids poor gut function.

It's trial and error what dose each person needs. Frequently with Hashimoto's we need higher dose than average

Local CCG guidelines

Government recommends everyone supplement October to April

B12 and folate on the low side. Supplementing a good quality daily vitamin B complex, one with folate in not folic acid may be beneficial.

B vitamins best taken in the morning after breakfast

Igennus Super B complex are nice small tablets. Often only need one tablet per day, not two. Certainly only start with one tablet per day after breakfast. Retesting levels in 6-8 weeks

Or Thorne Basic B or jarrow B-right are other options that contain folate, but both are large capsules

If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 7 days before any blood tests, as biotin can falsely affect test results

Low B12 symptoms

If vitamin D is low, B vitamins may be too. As explained by Dr Gominack

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