Thyroid UK
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Should I be worried about my 9am cortisol result?

Hi im new on here. I suffer from hashimotos thyroiditis and have been having yearly short synacthen tests for the past 3years. I had just a 9am cortisol done two weeks ago and the result was 171. Before having the test I had to convince the endo to do it as I previously had been told by others in his team that it should be yearly monitored to which he didn't think necessary! So he did it and upon requesting my results I asked again if I could have the SST and he responded by saying my 9am cortisol was probably ok but yes he will arrange for SST. Is 9am cortisol result of 171 rather low?

many thanks in advance

4 Replies

sarah, after years of suffering endos and GP's treating my Hashimoto's I've decided that this doctor of functional medicine has a better understanding of what is going wrong. He has a series of short videos and this one is regard to high cortisol which I think you will find very interesting.


Hi, Sarah, the lab taking the test provides its own ranges. They are the ones that help to assess if your result is within the range.


Yes it is on low side . Ideally above 193. However the important reading is the second one. That shows if your adrenals are responsive. It should triple. Be around 521.


Sarah86, have you ever had your pituitary function checked out? Low cortisol can be caused by the pituitary's failure to stimulate the adrenals with ACTH, and this doesn't show up on a short synacthen test obviously, because when the adrenals DO get stimulated, they often work fine.

According to Dr Peter Snyder's article on the Wolters Kluwer Health website

readings below 83 nmol/L clearly indicate cortisol insufficiency, and levels above 497 nmol/L equally clearly show there is no problem, but there is a grey area between these two figures between where caution has to be exercised, because hypocortisolism caused by pituitary dysfunction can be hard to detect. He says "A serum cortisol value of >83nmol/L but <497nmol/L that is persistent on repeat determination is an indication to evaluate ACTH reserve."

It looks to me as if you're well down in the grey area. If your other SSTs have shown a basal level of less than 497 nmol/L you have good grounds for asking for 'an evaluation of ACTH reserve' i.e. the insulin stress test or glucagon stimulation test. Do read 'Christine's Story' on (scroll to bottom) for a harrowing account of how hypopituitarism was missed because of the SST.


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