Learn how to stay healthy during COVID-19 with our free guide — Coronavirus: A guide to staying healthy (and sane) while stuck indoors

Quick Navigation

Cortisol

Cortisol is a hormone that mediates the stress response and sleep-wake cycle, being high in the morning and (hopefully) low in the evening. It triggers gluconeogenesis and a variety of other catabolic reactions. It isn't necessarily harmful or needing to be minimized, but excessive and chronically high cortisol can cause insulin resistance, endothelial dysfunction, reduced immune function, and other negative effects.

Our evidence-based analysis on cortisol features 54 unique references to scientific papers.

Research analysis led by .
Reviewed by
Examine.com Team
Last Updated:

Summary of Cortisol

Cortisol is a steroid hormone produced in the adrenal glands. It is the body’s primary glucocorticoid. It is most commonly associated with the stress response where it rises to trigger gluconeogenesis (the production of glucose) lipolysis (the liberation of fatty acids from glycerol), and glycogenolysis (the breakdown of glycogen to produce glucose), essentially making energy more freely available. This is important for when a threat or an urgency requires a quick burst of energy. In conjunction with other hormones, it participates in the formation of memories associated with stress and trauma.

It’s also involved in circadian rhythms and the regulation of diurnal energy levels, generally increasing upon waking, and decreasing throughout the rest of the day to (hopefully) be lowest at bedtime. High evening cortisol is associated with insomnia, and a flattening of the normal daily curve is correlated with a wide range of health issues.

Cortisol has an anti-inflammatory effect and is used as a topical anti-inflammatory drug (hydrocortisone). While many health issues derive from inflammation, chronic suppression can reduce the efficacy of the immune system, and this may be an explanation for the link between chronic stress and susceptibility to getting sick.

Most of the body’s cortisol is bound to corticosteroid-binding globulins, which prevent binding to glucocorticoid receptors, and cortisol must be freed before it. So much like with testosterone, what’s most relevant is the amount of unbound cortisol. Cortisol also has a less active form: cortisone. Cortisol testing tends to be of serum or salivary cortisol, though these are only reflective of transient and highly variable effects. Thus, testing on multiple days, continuous monitoring, or other tests such as hair cortisol may be more indicative of longer-term levels.

Get the latest information on 400+ supplements and their effects on 600+ health conditions & outcomes.

By becoming an Examine Plus member, you'll have access to all of the latest nutrition research. Quickly and easily look up scientific research on over 400 supplements across over 600 different health goals, outcomes, conditions, and more.

Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect cortisol.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Supplement Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-b Minor High See all 4 studies
In general, cortisol appears to be increased at high doses of caffeine; lower doses may not have an effect.
grade-b Minor Moderate See all 5 studies
Highly unreliable influences on cortisol, with decreases seen in studies where androgens and estrogens are also increased (with no significant influence or possibly an increase in other studies)
grade-b Minor Low See all 4 studies
A possible reducing effect of fish oil supplementation on cortisol

Become an Examine Plus member to view this information.

You can currently view 3 supplements as a non-member — becoming a member will give you access to 50 total supplements related to Cortisol.

Already a member? Login now to access.

grade-b  
grade-b  
grade-b  
grade-b  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-c  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  
grade-d  

Become an Examine Plus member to access the latest nutrition research on over 400 supplements across over 600 different health goals, outcomes, conditions, and more.

Becoming an Examine Plus member not only unlocks the Human Effect Matrix for supplements, but also all health topics on Examine.com. We neatly summarize all the latest research so you can make the best decisions for your health based on what's accurate and not out-dated information.

Frequently Asked Questions and Articles on Cortisol

How important is sleep?
Sleep is incredibly important, and can be considered crucial alongside diet and exercise. Proper sleep habits help sustain many biological processes, and bad sleep can cause these processes to be suboptimal or even malfunction.
Click here to see all 54 references.