High Cortisol blood test: I got my blood cortisol... - Thyroid UK

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High Cortisol blood test

Redporti profile image

I got my blood cortisol test results tonight. I did it at 8.15am. It was 983 (113-456). In March it was 907. Since the March test I have added T3 to my levo. I’m now on 40mcg of T3 in three split doses. I’m also on 50mcg of levo that I take at night.

I am waiting for the results of a cortisol saliva test I did the day before the blood test. Should I be worried that it’s so high?

11 Replies

T3 will increase your cortisol. I know this as it happened with me. My cortisol was under range. I started T3 as I’m a poor converter from T4 Levothyroxine. Within a few weeks after starting T3 my cortisol shot up to a high point in the range and has stayed there.

What’s your heart rate like with cortisol that high.

Redporti profile image
Redporti in reply to McPammy

My heart rate at rest is about 60 - 67 & moving around 76. I don’t have any palpitations & my blood pressure this morning was 106/69.

SlowDragon profile image
SlowDragonAdministrator

2 months ago you were on 20mcg T3

Now you are on double that ...that's a large increase over a short time

Blood should be retested 6-8 weeks after each 5mcg dose increase in T3

What are your latest thyroid results

Redporti profile image
Redporti in reply to SlowDragon

I’m due a thyroid test on 11th August.

My last test was 21st May.

TSH 0.008 (0.27-4.2)

Free T3 4.73 (3.1-6.8)

Free T4 13.200 (12-22)

SlowDragon profile image
SlowDragonAdministrator in reply to Redporti

How much T3 were you on then? 20mcg?

Essential to test vitamin D folate ferritin and B12 too

Make sure to do blood test as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test and last 1/3 rd of T3 dose 8-12 hours before test

Stop taking any supplements that contain biotin a week before any blood tests

Come back with new post once you get results

Redporti profile image
Redporti in reply to SlowDragon

I was on 30mcg T3 then. Vit d, b12, folate & ferritin are all good.

I’m going to ask for a 24 hour cortisol urine test too. I had high cortisol before I started T3.

Hi Redporti, have you ruled out the standard reasons for high cortisol (unrelated to the thyroid)? I had high cortisol a couple of years ago and the culprit turned out to be hormonal birth control. Getting my cortisol back to normal levels has made me feel much better.

I hadn’t thought of that. The thing is I’ve been on the pill 30 years & it’s only in the last 2 years that my cortisol has been high.

How did you feel when your cortisol was high?

I was incredibly tired, I couldn't really function. I think cortisol interacts with a lot of the thyroid hormones so it's really important to keep it under control.

There are a bunch of other reasons why cortisol may be high, I would talk to a doctor about this. My primary care phoned an endocrinologist to discuss possible reasons and the need for further testing, and birth control was one of the things the endo brought up. There were other things that were mentioned, like steroid medications, but I'm sorry I don't remember more.

I was on BC for a few years by the way, and didn't feel any worse right away, so I wouldn't rule this out. I don't have any cortisol measurements from earlier on though, so I don't really know what happened when I started taking BC. I just know I felt much better after I stopped.

I have just done a saliva test & tomorrow I’m doing a urine test. Then I will have all the cortisol tests done for when I speak to my Endo on 1st Sept.

I feel tired & off my food. Also not sleeping well but think that might be undiagnosed sleep apnea. I keep waking in the night choking & stop breathing.

Thanks for the insight. I will mention the BC too.

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