Short synthacen test


I recently had this test and my results are normal according to NHS endo. After looking at results most websites say your cortisol levels should double however mine didn't and the test was also done at 11 a.m.

The baseline cortisol was 438n mol/l

The peak cortisol after 60 mins was 654 nmol/l

Is this ok?

Am having trouble increasing my thyroid dose but still have symptoms and my blood pressure is increasing which doesn't concur with low adrenals.


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17 Replies

  • What prompted the test to be done?

  • Hi,

    Dr referred me to nhs endocrine as he would not prescribe from my private Dr. This was included in a battery of tests that were done. I am on a good amount of erfa and t4 but pain in joints and muscles and fatigue just won't seem to shift.

    I have tried upping dose several times but always feel overmedicated

    A lot of my symptoms have enormously improved and all my iron,b12,d3 etc is optimal.

    Cortisol was my last piece of the puzzle.

  • The short synacthen test is a get out for doctors, they do not know the difference between adrenal FAILURE and adrenal FATIGUE!!! I recently discovered vitamin and mineral tablets that support the thyroid and have started taking them with good results so maybe you need a vitamin and mineral check to see if you are getting all you need.

  • Yes I am considering that.


  • So if you are taking lots of t4' in the form of levo and NDT, perhaps it is just sitting in the blood or turning into reverse t3 .. If its pooling and not being got rid of, then this might be what is causing joint and muscle pain.

    You will be getting t3 from the NDT, so Perhaps no need for the t4 .

    Have you looked at getting an rt3 test alongside a free t3 test. So you can see what is happening? May be that you need t3 only.

    You would get more replies if you put this thread in questions, not in posts.....

    G X

  • Hi

    Have always had joint and muscle pain even before diagnosis. Just so disappointed it has not improved.


  • Hello,

    The synthacen test only shows up Addisons Diease, I had that test done and was told I was fine (clearly this was not the case) I went to see a private Dr who done the ASI test - this tests is done using saliva at four different times throughout the day - it's done in the comfort of your own home and came back that I had adrenal Fatique.

    Best wishes

  • Thank you will do the test

  • Here is a link to The Endocrinologist Handbook at it tells you exactly how doctors interpret the test.

    Moggie x

  • Thanks Moggie

  • Yes Kitten-whiskers is right that the synacthen test only shows up Addisons Disease i.e. when the problem is in the adrenal glands themselves. It is very insensitive for detecting when the problem is further upstream - not in the adrenals which can be fine, but in the pituitary gland, when the pituitary is failing to produce enough ACTH to stimulate them. If you look the synacthen test up on Wikipedia there's a reference to a review by Dorin showing it's only 60% sensitive.

    I think when Kitten-whiskers talks about 'adrenal fatigue' she means what most GPs would call 'secondary hypoadrenalism' (the 'secondary' means 'caused by the hypothalamus or pituitary') - and maybe using that terminology would make them listen more. Anyway, my recommendation would be that pippadoll asks for the insulin stress test, which is more unpleasant to go through, but much more sensitive and will definitely show whether her pituitary is working properly (it assesses growth hormone reserve as well).

    If she's ever had a head injury, autoimmune disease, cranial radiation, a stroke this can cause pituitary dysfunction. Also tiny tumours (not cancerous) can cause it too.

  • Hi,

    I was tested for IGF-1 and it came out middle of range also I have included more t4 (50mcg) as my t4 dropped to 15 (12-22) on 3 grains of erfa and my t3 was top of the range. I have had a reverse t3 test and it was 17 so less than 20 which shows some pooling. However more t3 makes me feel overmedicated so now on 2 he erfa and the t4.

    I have symptoms of both high and low cortisol and strokes do run in my family. Blood sugar is high at 6.2. I will look into glucose test and saliva cortisol.

    Many thanks

  • Thank you Pippadoll for telling me this. I can't comment on the T4/T3/reverseT3 scenario because I just don't know enough about that - have to read it up! The only useful thing I can tell you is that although normal IGF-1 is often thought to exclude growth hormone deficiency, it actually doesn't, see this quote:

    Cleveland Clinic, Center for Continuing Education, Pituitary Disorders, Skugor M, Hamrahian AH, “Random measurements of GH and gender- and age-adjusted insulin-like growth factor-1 (IGF-1) levels are not reliable to diagnose GH deficiency because GH secretion is pulsatile, and up to 65% of patients with GH deficiency have a normal IGF-1 level. Therefore, GH deficiency is best evaluated by dynamic testing, including the insulin tolerance test or GH-releasing hormone (RH)/arginine test.”

  • Thank you. I will print that out and take it to my next endocrine visit. Another useless test.

  • Also my original thyroid blood tests were very low in range tsh and t4. My private doc diagnosed me but all my 3 children have same blood test levels with hypothyroid symptoms but because the TSH Is low we cannot get diagnosed on NHS.

    Menstruation stopped when I was 40, same as my mum and sister (both deceased) but trying to find out the genetic link for problems with the pituitary or hypothalamus is hard going.

    Thanks for your responses.

  • Hi Pippadoll I wish you the best in your quest for proper treatment. It shouldn't be like this . .

  • Synacthen tests are used for distinguishing types of adrenal hypofunction. This is to possibly exclude the presence of under active adrenal gland; in particular, Addison's disease which is an auto immune condition that results in under active adrenal gland.

    It is done in the morning because plasma cortisol level changes with diurinal rhythm, and so its normally high in the morning. However, cortisol levels can be influenced by stress, steroids, oral contraceptives.

    Two measurements are taken, the basal (before the injection of synacthen) and 30-60mins after the injection.

    This is to see if your adrenal gland has responded to drug and so the presence of the drug stimulate the adrenal gland to produce cortisol.

    If the results show <500nmol/l, then that indicates a potential addison's disease (unsastifactory response). If 500nmol/l or higher, this excludes the potential diagnosis for addison's. (i.e. adrenal function seems to be satisfactory)

    the value of 654nmol/l is still over 500 and this result should not be a concern.

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