The Cortisol Weight-Loss Controversy

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Cortisol is a key hormone in metabolism and it affects your body's response to stress, but its relationship to weight gain and weight loss is complicated.

For some people, high levels of cortisol can lead to overeating and weight gain.

Marketers of supplements that claimed to block cortisol to produce rapid weight loss ran afoul of the U.S. Food and Drug Administration. Targeting cortisol is simplistic, and if products had a significant impact on cortisol levels, they would likely have serious side effects.

Understanding the role of cortisol in the body can help you weigh the validity of health claims that tout effects on cortisol.

Female leg stepping on weigh scales. Healthy lifestyle, food and sport concept.
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What Cortisol Does

Cortisol is an important hormone that helps your body manage many vital functions, including your energy level. Your body makes and uses cortisol every day, throughout the day and night.

Your hypothalamus, via the pituitary gland, directs the adrenal glands to secrete both cortisol and adrenaline.

These hormones can also be released in reaction to perceived stress—both physical and emotional—as part of the fight-or-flight response that's essential for survival.

  • Cortisol helps your body become more effective at producing glucose from proteins, and it helps quickly increase the body’s energy in times of stress.
  • Adrenaline makes you energetic and alert and increases metabolism. It also helps fat cells release energy.

When your cortisol production is repeatedly elevated for a prolonged period of time, as occurs with a constant state of stress, this can cause many health effects. Weight gain can be one of the effects of chronically high cortisol.

Effects of Excess Cortisol

Excess cortisol stimulates glucose production. This excess glucose is then typically converted into fat, which gets stored in your body. For example, people with serious metabolic conditions that involve excessive cortisol production, such as Cushing syndrome, have an unhealthy increase in abdominal fat.

A chronically high level of circulating cortisol increases fat storage and raises the risk of obesity. And when you have too much adrenaline, fat cells eventually become less responsive to adrenal stimulation to release fat.

Of particular concern is abdominal weight gain—one of the most dangerous types of obesity, and one that contributes to an increased risk of metabolic syndrome, diabetes, and heart disease.

Some studies have found that stress-induced cortisol levels can cause people to increase the amount of food they eat.

Insulin Resistance and Cortisol

Insulin resistance is another potential problem that can develop due to chronically high cortisol levels. Sustained increases in cortisol, such as from taking steroid medications, can result in insulin resistance. Other causes of insulin resistance include genetics, obesity, and lack of physical activity.

In insulin resistance, the brain and some of the body’s cells have decreased responses to insulin, so too much glucose continues to circulate in the bloodstream.

This can lead to type 2 diabetes. Insulin resistance is sometimes called pre-diabetes.

Metabolic syndrome is diagnosed once insulin resistance results in abdominal obesity, low HDL cholesterol levels, high blood pressure, and high fasting glucose levels.

Reducing Cortisol

Since cortisol contributes to abdominal obesity, one might follow that line of thinking and conclude that they should take steps to block it to prevent belly fat or encourage weight loss. It's not that simple.

Reducing cortisol with medication is done slowly and with great care. This process is known as tapering.

For example, if you are prescribed a corticosteroid drug such as prednisone (which raises cortisol), you will be instructed to slowly reduce the amount over a number of days rather than simply stopping the drug.

This is because the feedback loop of the hypothalamic-pituitary-adrenal axis reacts to high cortisol levels by shutting down your body's own production of cortisol, which will take time to ramp up again to provide enough for your necessary metabolism.

An abrupt decrease can result in symptoms such as fatigue, fever, muscle and joint pain, and psychiatric symptoms.

You need cortisol to perform essential metabolic functions, and abruptly blocking cortisol in an attempt at weight management would have unpleasant or dangerous side effects.

Cushing syndrome is caused by a hormone-producing tumor. A cortisol-reducing drug may be given before the tumor is removed. However, these drugs need to be carefully monitored because sudden fluctuations in cortisol can produce significant side effects.

This is because the drugs used to reduce cortisol in Cushing syndrome can cause hyperglycemia, diabetes, and dangerously low potassium levels.

Supplement Claims

Supplements that claimed to reduce the effects of cortisol in order to promote weight loss were heavily advertised in the early 2000s.

One such, CortiSlim, was subject to a Federal Trade Commission (FTC) action over such claims. As a result, the manufacturer changed its advertising and eventually went out of business.

The FDA also notified the manufacturer that their claims that the product controlled cortisol in a healthy range and helped lose weight were unsubstantiated.

According to the FDA, it didn't work. In fact, if it worked as claimed, it would need to be regulated as a drug.

Other supplements such as phosphatidylserine are claimed by some to reduce the brain's reaction to stress, thus reducing cortisol and assisting in weight loss.

Weight loss products citing a cortisol-blocking effect may come and go in popularity. They are classified as dietary supplements, which means they are not required to undergo testing or research to back up these claims.

A Word From Verywell

Rather than a supplement, the Centers for Disease Control and Prevention (CDC) and other health authorities recommend behavioral changes that will reduce your stress level and help reverse insulin resistance.

These include:

  • Focus on becoming stress-resistant. One of the best things to reduce stress and improve insulin sensitivity, for example, is getting regular exercise, even a daily brisk walk.
  • Practice stress-reduction techniques such as yoga, tai chi, meditation, breathing exercises, anger management therapy, therapeutic massage, listening to calming music, or others. These sort of approaches can help reduce your body’s physiological response to daily stressors.
  • Get enough sleep. Chronic sleep deprivation increases stress, reduces immunity, and makes it more likely that you’ll be overweight.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Federal Trade Commission. Notice of potential illegal marketing of products that claim to cause weight loss, reduce the risk of disease, or produce other health benefits by affecting the stress-related hormone cortisol: immediate action required.

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  5. Kelsall A, Iqbal A, Newell-Price J. Adrenal incidentaloma: cardiovascular and metabolic effects of mild cortisol excessGland Surg. 2020;9(1):94–104. doi:10.21037/gs.2019.11.19

  6. Geer EB, Islam J, Buettner C. Mechanisms of glucocorticoid-induced insulin resistance: Focus on adipose tissue function and lipid metabolismEndocrinol Metab Clin North Am. 2014;43(1):75–102. doi:10.1016/j.ecl.2013.10.005

  7. Centers for Disease Control and Prevention. The insulin resistance–diabetes connection.

  8. International Diabetes Federation. IDF worldwide definition of the metabolic syndrome.

  9. Hospital for Special Surgery. Steroid side effects: How to reduce drug side effects of corticosteroids.

  10. Oregon Health Sciences University Brain Institute. Cushing disease/Cushing syndrome.

  11. U.S. Food and Drug Administration. FDA Warning Letter to CortiSlim.

  12. Federal Trade Commission. Consumer Information. Dietary supplements.

By Mary Shomon
Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution."