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Cortisol is generally best known as the “stress hormone.” However it’s truly amazing how its concentration –high or low– can set off a cascade of changes in the body that can be difficult to restore back to balance. But, there’s a hack for that! Read on…or check out my ebook, SelfHacked Secrets to find out which supplements and biohacks have helped me balance my cortisol levels and feel better than ever. Click here to receive the first chapter for free.

Cortisol is a very important marker to monitor, especially if you haven’t been leading the best lifestyle or you have chronic health issues. With Lab Test Analyzer you can track cortisol levels and make sure they are always in the optimal range. Why wait until issues get out of hand and interfere with your work and daily life? Lab Test Analyzer has got you covered – it tracks your health and gives you actionable advice on how to improve it.


Introduction to Cortisol

Cortisol is a hormone synthesized in the adrenal glands.  Cholesterol is the first ingredient in the production of cortisol.

Cortisol is released when people experience stress, in order to address the changes that occur in the body.

Cortisol also controls blood sugar levels, fat-, protein-, and carbohydrate metabolism, immune responses, anti-inflammatory action, blood pressure, heart- and blood vessel tone and contraction, and central nervous system activation.

How it Works: A Scenario

A typical scenario would be someone facing a mugger on the street. This causes stress on the individual. The adrenal glands produce cortisol in response to the increased stress levels.

Cortisol fills the blood with glucose to be used by the muscles for energy. Insulin is restricted so glucose can be readily used instead of stored.

Arteries are narrowed to increase blood pressure, and epinephrine increases the heart rate. This makes the heart work harder and lets the individual react quickly to the situation.

The person being mugged will either fight the mugger or run away. Either way the situation is resolved and cortisol levels should go back to normal. Glucose can be stored once again and insulin is no longer restricted.

Cortisol reduces the impact of stress on the body and returns it back to homeostasis levels.

Cortisol’s Role in Blood Sugar Levels


Cortisol’s anti-insulin effects are there to increase glucose uptake and usage in the brain, heart and muscles (R). These are the places that need it most when you’re running from a mugger.

Cortisol increases glucose production and reduces glucose uptake in certain tissues (R).

Cortisol makes glucose from glycogen (the storage form of glucose) in response to stress. This provides immediate metabolic energy so that the body can function and react to the situation.

Cortisol reduces glucose delivery to some tissues by impairing local blood flow (such as to the stomach and digestive system) while it increases blood flow to heart and leg muscles (R).

If the situation is too stressful, this can cause abnormally high blood sugar levels because of all the glucose released into the blood to address the situation.

Cortisol simultaneously stimulates both glucose storage (glycogen synthesis) and glucose breakdown (glycogenolysis) (R). It depends on other factors like insulin levels.

When there’s low insulin and high adrenaline, cortisol may cause a more effective release of fuel and higher glucose output. When there’s high insulin, cortisol may promote glycogen (glucose) accumulation (R).

Cortisol Affects Electrolytes

Cortisol acts as a diuretic, which leads to water and potassium excretion and sodium retention.  It increases potassium excretion in the intestines as well (which might affect the gut flow) (R, R2).

I ask in my questionnaire whether people urinate frequently to get a pulse on their cortisol (and vasopressin) levels. Some people have reduced cortisol after a long period of chronic stress.

As it is, our modern diets are extremely imbalanced in that we get too much salt and too little potassium. HPA activation by stress will therefore worsen this imbalance.

Anxiety and its associated increase in various neurotransmitters increases magnesium excretion (R).

Cortisol also decreases calcium uptake in the kidneys and more of it is released in the urine instead of being utilized, which may cause calcium deficiency and kidney stones. Normally, aldosterone increases calcium reabsorption, but cortisol competes with it (R).


Cortisol’s Positive Effects

While high levels of this stress hormone are problematic, low levels aren’t good either. Cortisol is absolutely essential for everyday energy and functioning of the body.

Cortisol counteracts stress and increases energy by burning fat for fuel.

Cortisol decreases hypoglycemia (low blood sugar) by increasing blood glucose. When I have a thin client who suffers from hypoglycemia, it suggests that his or her cortisol levels might be chronically or intermittently low. This is one the main defining features that separate the hypoglycemics from those who don’t get hypoglycemia often.

Cortisol stimulates internal antioxidants such as SOD (Superoxide Dismutase) (R).

Cortisol stimulates stomach acid secretion, which can help with thorough digestion (R).

Cortisol’s Negative Effects

1) Cortisol Leads to Weight Gain


Cortisol causes weight gain, on the whole. It is one of the big 4 hormones that determine weight.

Cortisol secretion is elevated in obesity, but blood levels are normal because it gets deactivated. It’s in fat tissue itself that cortisol is elevated (R).

Cortisol is associated with increased appetite, cravings for sugar, and weight gain in both animal and human studies (R). My brief experiments with Hydrocortisone led to increased cravings.

Cortisol seems to directly influence food consumption by binding to receptors in the hypothalamus. This can stimulate an individual to eat food that is high in fat and/or sugar (R).

Women with a higher cortisol response chose to consume more foods high in sugar and fat (R).

Cortisol also indirectly influences appetite by regulating other hormones that are released during stress such as CRH, leptin and NPY (neuropeptide Y).

Cortisol increases leptin secretion from fat cells (R).

Cortisol decreases insulin secretion and increases insulin resistance, which will raise insulin levels in the longer term (R).

Besides leading to diabetes, this also depletes cells of energy and they signal the body to replenish energy stores: “EAT!”

2) Cortisol Impairs the Brain


The hippocampus (memory center) contains many cortisol receptors. Excess cortisol overwhelms the hippocampus and actually causes it to decay (R).

Cortisol/Glucocorticoids impair declarative memory retrieval and working memory (WM) performance (R).

Cortisol stimulates liver detoxification by inducing tryptophan oxygenase, which also has the effect of reducing serotonin levels in the brain (R).

Cortisol also induces glutamine synthase, which reduces glutamate levels in the brain (not good if it’s too low or too high) (R).

Studies of the elderly show that those with elevated cortisol levels display significant memory loss. The damage is usually reversible (R).

Stress also decreases neurogenesis, or the ability to create new neurons, in our memory centers (hippocampus) (R).

3) Cortisol Weakens the Immune System


Since cortisol works to decrease stress-induced inflammation, it also weakens the immune system, which makes people are more susceptible to sickness.

Cortisol weakens the activity of the immune system by:

  • Causing the thymus (which is responsible for immunity) to decay (R).
  • Inhibiting IL-12, interferon gamma and alpha, TNF and Th1 cells (R).
  • Increasing IL-4, IL-10, and IL-13 by Th2 cells (R).
  • Inhibiting Histamine secretion (R).
  • Reducing production of T-cells by making them unresponsive to IL-1, which lessens IL-2 (a T-cell growth factor) (R).
  • Inhibiting Natural Killer Cells (by inhibition of natural cytotoxicity receptor. Prolactin activates) (R).
  • Inhibiting NFκB (R).

Cortisol decreases the Th1 response and favors more of a Th2 response. It inhibits IgM and IgA, but not IgE antibodies (R).

4) Cortisol Contributes to Cardiovascular Disease


Because of the increase in blood pressure in constricted vessels, it is possible for cortisol to cause heart attacks. Constant cortisol release damages blood vessels.

Cortisol will cause higher blood pressure by retaining sodium, excreting potassium and by making your blood vessels contract (R, R2).

In the absence of cortisol, widespread vasodilation (relaxation of blood vessels) occurs (R).

Cortisol also increases blood pressure by increasing the sensitivity of blood vessels to epinephrine and norepinephrine (R).

A 2010 study found that blood cortisol predicts increased death from heart disease (R).

5) Cortisol Contributes to Osteoporosis

Cortisol reduces bone and collagen formation (R).

It decreases osteoblasts and therefore will lead to decreased bone density (by inhibiting periosteal cells) (R).

Cortisol also reduces calcium absorption so you will be deficient in calcium (R).

Indeed, various studies show that higher cortisol is associated with lower bone mineral density in people (R, R2).

6) Cortisol May Result in Sexual Dysfunction

Cortisol levels that are too high can also impede sexual activity. When cortisol is being overproduced, the sex hormones are not being produced in their usual quantities, since they are produced in the same place, the adrenal glands.

Cortisol shuts down the reproductive system, resulting in an increased chance of miscarriage and (in some cases) temporary infertility (R).

7) Cortisol Makes it Difficult to Build Muscle


In chronic stress, growth hormone is decreased (R).

Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.  This means we won’t build muscle as well (R).

Cortisol also breaks down muscle (R).

Collagen is a molecule that makes connective tissue. It is vital for structural support and is found in muscles, tendons, and joints, as well as throughout the entire body. Cortisol inhibits collagen (R).

8) Cortisol Delays Healing

High levels of perceived stress and increases in cortisol have been found to lengthen wound healing time in healthy, male adults (R).

Those who had the lowest levels of cortisol the day following an injury had the fastest healing time (R).

Cortisol delays wound healing (R).

In dental students, wounds (punch biopsies) took an average of 40% longer to heal when performed three days before an examination as opposed to wounds on the same students during summer vacation (R).

9) Cortisol Increases Anxiety and Depression

Cortisol activates the “Kynurenine Pathway”, which shunts tryptophan to make a molecules that will cause neuron loss, anxiety and depression (Kynurenine, Quinolinic acid), instead of making serotonin (R).


10) Others

In rats, cortisol caused 10X greater collagen loss in the skin than in any other tissue (R).

Cortisol stimulates many copper enzymes, probably to increase copper availability for immune purposes (chronically elevated copper isn’t good) (R).

If you have high cortisol, you will do worse with a high salt diet and you will be potassium deficient in the long term (few people as it is get the RDA). But taking potassium supplements is not simple, because the deficiency is in your cells, not your blood.  Also, potassium raises cortisol, which isn’t good if you already have high levels. Cortisol is anti-inflammatory, but it can also cause arthritis by inhibiting collagen formation and also by lowering cell potassium. Cell potassium is always low in rheumatoid arthritis (R). The answer is to reduce stress.

Other possible effects are mental illness or a decrease in mental function (memory or learning), increased cholesterol levels, and lower life expectancy (R).

High or Low Cortisol Causes

See a comprehensive list of reasons why your cortisol is low or high.

Causes of High Cortisol

High cortisol levels can be caused by Cushing’s syndrome, a disorder in which the body has too much cortisol, and Cushings can in turn be caused by overactive adrenal glands, an adrenal gland tumor, or by steroids (R).

In Cushing’s syndrome, there is an accumulation of fat in the belly, neck and cheek, but a decrease of fat in many other places. (R) There may also be accumulation of fat in the liver in Cushing’s syndrome (R).

Cortisol can also be elevated due to liver or kidney disease, obesity, depression, pregnancy, sickness, and injury (R).

Cortisol can be increased in production by viral infections, caffeine, not sleeping, intense or long aerobic exercise like running or climbing stairs, not eating, low calorie food, high stress, among other things (R).

Causes of Low Cortisol

Low cortisol can be caused by Addison’s disease, a condition in which the adrenal glands cannot make enough cortisol, or due to problems with the pituitary gland – cortisol’s next stop after being released from the adrenal glands (R).

PTSD is associated with lower cortisol and higher DHEA (R).

Circadian rhythm disruption can cause low cortisol. In animals, light at night alters daily patterns of cortisol and clock proteins (R, R2). In humans, it also alters circadian clocks (R).

What Increases or Decreases Cortisol?


Everyone is different and our bodies can be complex. If you want to increase/decrease your cortisol levels, it’s best to analyze them with Lab Test Analyzer. This tool will compute, based on this and your other results, the best steps you can take that will bring you back to optimal.


See these posts:

Irregular Cortisol Levels?

If you have not yet tested your cortisol levels, I recommend that you ask your doctor to do it. If you already have your blood test results and you’re not sure what to make of them, you need to check out Lab Test Analyzer. It does all the heavy lifting for you. No need to do thousands of hours of research on what to make of your various blood tests.

People don’t realize that their blood test results contain a gold mine of information that’s waiting to be unearthed. Unfortunately, not everyone has the time or the inclination to sift through dozens of research papers.

It’s super-simple, so that even if you don’t have any background in science, you will understand what your results mean and what you can do to get them in the optimal range.

Lab Test Analyzer gives you up-to-date scientific information about your lab results. In addition, you will get both lifestyle tips and natural solutions to help you optimize your health. You can also rely on our science-based Optimal Ranges to prevent potential health issues and maximize your overall well-being.

All of the content is backed by science and researched by a team of PhDs, professors, and scientists.

We’re all unique, so we deserve solutions that treat us that way.

Health Tools I Wish I Had When I Was Sick

At SelfHacked, it’s our goal to offer our readers all the tools possible to get optimally healthy. When I was struggling with chronic health issues I felt stuck because I didn’t have any tools to help me get better. I had to spend literally thousands of hours trying to read through studies on pubmed to figure out how the body worked and how to fix it.

That’s why I decided to create tools that will help others cut down the guesswork:

  • Lab Test Analyzer – a software tool that will analyze your labs and tell you what the optimal values are for each marker — as well as provide you with actionable tips and personalized health and lifestyle recommendations to help you get there.
  • SelfDecode – a software tool that will help you analyze your genetic data from companies such as 23andme and ancestry. You will learn how your health is being impacted by your genes, and how to use this knowledge to your advantage.
  • SelfHacked Secrets – an ebook where we examine and explain the biggest overlooked environmental factors that cause disease. This ebook is a great place to start your journey if you want to learn the essential steps to optimizing your health.
  • SelfHacked Elimination Diet course – a video course that will help you figure out which diet works best for you
  • Selfhacked Inflammation course – a video course on inflammation and how to bring it down
  • Biohacking insomnia – an ebook on how to get great sleep
  • Lectin Avoidance Cookbook – an e-cookbook for people with food sensitivities
  • BrainGauge – a device that detects subtle brain changes and allows you to test what’s working for you
  • SelfHacked VIP – an area where you can ask me (Joe) questions about health topics

FDA Compliance

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.


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  • Tim

    I have read everything on this site about cortisol and PTSD and anxiety and not one mention of how to raise cortisol..? Every anxiety remedy on here just makes me more spaced out sleepy and difficulty in verbal communication.. I’ve got brain fog aspergers and social anxiety. No friends because I can’t talk or socialise. Too nervous and my mind is blank. I don’t have $500 to converse with jo,but even if I did it wouldn’t help because I wouldn’t be in the ‘zone’ to ask the right questions that I would need. Tried many supps and have a full list of all the side effects they all cause. Man, why no help for low cortisol. I can’t even find anything on selfdecode that helps.

    1. Caroline Lam

      Hi Tim, in that article, it mentions possible causes of low cortisol. If you have circadian rhythm disruption, perhaps you can see if fixing that fixes your cortisol levels. You can try LabTestAnalyzer to monitor your cortisol or SelfDecode for gene reports on sleep (and other information related to genetic markers).

      Hope that helps!

  • Norm

    After extensive reading and research I’m losing weight and have extreme fatigue. I just would like a trial of cortisol to see for myself.

  • Leann

    I have adrenal tumor and muscle tension and stiffness a crazy rash on neck and shoulders and my absolute lymphs were 4.1 extreme fatigue…I was a 12 year meth addict..and wonder what the crap I may have done to my body…clean for 5yrs…also have heirtisum

  • nugent76

    I disagree that: [psychology today]


  • Astral Pharoh

    One minute you say cortisol gives you energy. Then the next minute you say it causes fatigue. Can you please clear this up for for me? Thanks buddy

    1. E


      From my knowledge, at first high cortisol levels stimulates energy in the body, but after a prolonged period of high cortisol your body’s ability to balance out this ‘overdrive’ becomes strained. This can cause, and show symptoms of chronic fatigue. Thats why when you are attempting to balance high cortisol levels, it is often a difficult situation, as some people have been on ‘overdrive’ with their cortisol stress levels for so long, it becomes a case of dealing with low cortisol levels. The irony in the issue. I may be wrong in my explanation, i am not an expert. This is based on limited research.

  • Kelly Elizabeth Mulder

    Where’s the hack? 😉

    1. Joseph M. Cohen

      You need to read the other posts 😉

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