Low Cortisol or Hypocortisolism or Adrenal Fatigue?

I got asked a question today from a patient who wondered if the adrenals would recover from 'adrenal fatigue' over time or need adrenal cortex support or with the help of correcting iron levels.

I have been asked this a lot and this time I have taken the core of my answer and put it here in a blog post:

I don't think adrenals get weak, or sick, or damaged UNLESS someone has autoimmune disease that is attacking their adrenal glands, or a tumour or an accident that damages them.

I don't believe in Adrenal Fatigue any longer. I've worked too much with thyroid researchers over the last few years and it has changed my views in this area.

I never use the term Adrenal Fatigue now. I use hypocortisolism or just low cortisol.

Let me be clear, YES, of course low cortisol is a massive problem for many thyroid patients. This is NOT in question - it is just the cause of it that I am discussing. The terminology also needs to be clearer.

My books have ALL been updated to reflect this view.

The adrenal glands are incredibly simple organs. They keep making cortisol in as much quantity as someone needs, as long as there is enough ACTH (the stimulating signal from the pituitary) and enough cholesterol in the bloodstream. They just can go on and on. This is often why people with Cushing's syndrome (incredibly high cortisol), keep having high cortisol for years until they are diagnosed.

The main cause for non-Addison's hypocortisolism is hypothalamic-pituitary axis dysfunction - often of unknown origin, but sometimes because of low FT3.

The pituitary produces ACTH. It is the main signal to stimulate the adrenals to make cortisol, Dhea and to some much lower extent aldosterone.

The pituitary converts T4 to T3 very efficiently within its own cells, if it makes the D2 deiodinase enzymes correctly. Gene defects with D2 (the DIO2 defect), can wreck this conversion.

The pituitary has been discovered to have the highest concentration of FT3 out of all the different tissue types in the body. It needs high FT3.

Thyroid patients who don't have enough FT3 will not be giving their pituitary the help it needs.

Daytime dosing of thyroid meds often leads to low nighttime FT3 levels. 

Some people also have poor conversion - leading to low FT3 levels. 

Any DIO2 gene defect will contribute to lower pituitary FT3 than it was supposed to have.

Loss of thyroid tissue, through Hashimoto's or thyroidectomy also loses a signficant amount of conversion capability. Thyroid patients without a thyroid typically lose about 25% of their ability to make T3 (mostly through conversion) - this conversion capability cannot be replaced.

I no longer think 'adrenals need to heal'. I believe that there can be hypothalamic-pituitary dysfunction - often after prolonged stress, and often because of daytime dosing of thyroid medication and sometimes due to poor conversion or other issues.

Fixing factors that influence conversion like iron, vitamins and selenium can help, but won't fix it if there is a fundamental issue like thyroid tissue loss or one of the gene defects.

Sometimes it needs the raising of FT3. Sometimes this raising needs to happen in the night - hence my Circadian T3 Method (CT3M).

Sometimes, there is no obvious reason for the problem. However, I do believe it resides in the hypothalamic-pituitary area - not the adrenals.

Trying to 'support the adrenals' using adrenal cortex in the hope that they will just get better is not something I believe will work at all.

If there is a massive reason like incredibly low iron, which can be worked on whilst using adrenal cortex, it can be helpful. But just taking the cortex is not a solution to make the adrenals be healthy again. 'Resting' them isn't a solution.

The two tests to rule out real organ issues are:
1) The ACTH Stimulation or Synacthen test - this tests whether the adrenals can respond to ACTH stimulation. If they do well, the adrenals aren't the issue - most thyroid patients pass this.
2) The Insulin Tolerance Test - this tests if the pituitary is capable of responding to much lower blood sugar and produce enough ACTH. It doesn't prove there isn't any hypothalamic-pituitary 'dysfunction' but it rules out proper hypopituitarism.

*** end of my answer ***

The above information is in ALL of my books now - including the updated 2018 editions of 'Recovering with T3' and 'The CT3M Handbook' and 'The Thyroid Patient's Manual'. It is ALL in there and more besides.

The term 'Adrenal Fatigue' is discussed all over the Internet. It is even present in some cortisol saliva test companies test results. In terms of cortisol saliva test results, I am one of the biggest fans of doing these. It is just the term that I think is misleading. When people talk of 'stages of adrenal fatigue', it simply means stages of failure to produce cortisol and dhea (both of which are stimulated by ACTH). It isn't just nomenclature or giving things the right name. It is about understanding what is really causing the problems. 'Nursing the adrenals back to health' by supporting with adrenal glandulars or adrenal cortex, is not going to fix the fundamental issue with low cortisol. I  realise that a lot of these comments may cause consternation, but I believe them with all my heart - based on the research I have done, the incredibly smart people that I have spoken with, and the experience I have had with working with many low cortisol patients.

When I had such low cortisol that I passed out cold on most days - when I stood up, or got stressed by anything, my doctors said that I had no issue with cortisol. I had been given a Synacthen Test (an ACTH Stimulation Test). The Results of the Synacthen Test were great - lots of cortisol being made and I felt good for a few hours. BUT, a morning cortisol blood test was very low. I had low cortisol symptoms and very low blood pressure. When I eventually asked my family doctor to do the only useful test that existed at that time, a 24-hour Urine Cortisol Collection and it was almost flat lined - as low as it could be. My adrenal glands responded great to ACTH, but I could not make cortisol in good enough levels normally as my pituitary wasn't doing its job. This is not me-specific. It happens a lot It happens for a lot of reasons - see my books for more details.

I suggested to the person that asked the question that they talk to me directly, as trying to give general answers without a lot of detail just does not help  in many cases.

I hope you found this helpful.

Best wishes,


(Updated in February 2019)