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The last blog entry posted related to adrenal fatigue was on self-diagnostic tests that could be performed at home. These tests can help you determine if more testing is needed to find out the state of health of your adrenal glands. Today we are going to discuss one of the diagnostic tests that are laboratory performed, the adrenocorticotropic hormone (ACTH) stimulation test.

What is Adrenocorticotropic Hormone and Its Function?

ACTH stands for adrenocorticotropic hormone (corticotropin) and is a hormone that is produced by the pituitary gland to stimulate your adrenals. ACTH causes the adrenal glands to up-regulate the production of corticosteroids. 1

ACTH binds to ACTH receptors that are primarily located within the adrenal cortex and stimulates the secretion of glucocorticoid steroid hormones. 2

Short rapid actions of ACTH release cause increased cholesterol delivery to the adrenal mitochondria which greatly increases cholesterol bio-availability within the mitochondria. The increased bio-availability of cholesterol is needed to produce the greater amount of corticosteroids needed by the body after ACTH is up-regulated by the pituitary gland. 3

Long term actions of ACTH on the body include stimulation of the transcription of the genes coding for steroidogenic enzymes and production of the associated electron transfer proteins important for mitochondrial function. ACTH increases the transcription of mitochondrial genes that encode subunits of mitochondrial oxidative phosphorylation systems that are necessary to supply the enhanced energy needs of adrenocortical cells stimulated by the ACTH. 4 5

The ACTH Stim Test and The Problems Associated With Its Use In Diagnosing Adrenal Fatigue

During an ACTH stim test, synthetic ACTH is injected into your body, and the adrenal release of cortisol and aldosterone into the blood are measured over a period of time to determine adrenal function. 6

The ACTH stim test requires you to fast eight hours before the test. Medication / herbs that can affect adrenal output including spironolactone, licorice, contraceptives, corticosteroids, DHEA, estrogen, and progesterone can influence test results and may cause a false positive or negative. Common side effects of the test include nausea, anxiety, dizziness, itchy skin, palpitations, injection site issues, and facial flushing. These side effects should disappear within a few hours after the test. Serious side effects that rarely occur include rash, fainting, headache, blurred vision, swelling, trouble breathing, irregular heartbeat. 7 8 9

The ACTH stim test can easily detect if one has Addison’s disease (a condition where the adrenal glands barely function,) a pituitary tumor or a tumor of the hypothalamus. Your doctor can determine if you suffer from any of these conditions depending on how your body reacts to the injected ACTH. The ACTH stim test, however, is very poor at determining adrenal fatigue because: 10

  1. The test uses a bell curve to spot abnormal cortisol levels and only considers the test results to be abnormal if you fall within 2% of the upper and lower part of the curve. For example, it would show if you were suffering from Addison’s disease because it would easily fall outside of the bell curve and show that your body produced no cortisol when stimulated.
  2. The test only measures the adrenal’s ability to be stimulated to produce corticosteroids not its ability to produce corticosteroids adequately. It will show if your adrenal glands cannot produce  corticosteroids or if the produce way too much BUT not if they have issues producing what is needed during the day for you to function optimally.
  3. The adrenal stimulation that you receive from the artificial ACTH is very potent compared to what your body would produce normally. If you have Addison’s disease, for example, it will not matter how much ACTH your adrenal glands receive, they would still fail to produce cortisol.

The ACTH stim test might be important in the discovery of adrenal failure (Addison’s disease) or certain brain tumors but it is useless in determining adrenal fatigue. Our next blog in the series will cover another, for the most part, useless test, which most doctors will order if you think you have adrenal issues.

A single drawn blood cortisol test.