The relationship between weight and cortisol is complex. Cortisol blockers can help reduce high levels for people with disorders affecting the adrenal glands that cause high cortisol levels.

Cortisol is a hormone that affects several bodily functions, but many people know it as the stress hormone. That’s because it helps your body function in times of stress. Your cortisol levels fluctuate throughout the day, but consistently high cortisol levels might indicate an underlying issue.

Cortisol blockers can help decrease cortisol levels in people with high cortisol-level disorders who may not be able to have surgery. This may include Cushing syndrome, which causes cortisol levels to be higher than the standard range.

However, companies also market some cortisol blockers as dietary supplements that can help you build muscle, lose weight, and feel less hungry.

To determine whether these claims are true, it helps to know what cortisol is and its role in your health.

When you feel fear or danger, a section of your brain called the hypothalamus activates your fight-or-flight response. The adrenal glands respond by releasing the stress hormones cortisol and adrenaline. Cortisol is the primary stress hormone.

Cortisol’s job is to streamline your body’s workload so you can concentrate on the immediate threat. The hormone adrenaline tells your heart to beat faster. It also boosts your blood pressure and increases energy.

Cortisol has a number of effects on the body. These can include:

  • acts on the panceas to decrease insulin, which makes your blood sugar, or glucose, levels rise
  • driving circulating glucose to the brain, improving alertness
  • enhancing your body’s ability to repair tissue

Cortisol levels naturally fluctuate throughout the day. Without a threat, your cortisol level is highest when you wake in the morning and lowest when you’re ready for sleep. Children tend to have less cortisol than adults.

Aside from stress, several factors can affect cortisol levels, including:

  • pituitary gland conditions, or tumors near the pituitary gland that produce the adrenocorticotropic hormone (ACTH)
  • adrenal gland tumors or conditions
  • some medications, including oral contraceptives and corticosteroids, such as prednisone and methylprednisolone

Consistently high cortisol levels can cause a rare disorder called Cushing syndrome, or hypercortisolism. Treatment for Cushing syndrome may include a cortisol blocker.

Symptoms of Cushing syndrome can include:

High cortisol levels can indirectly cause some people to gain weight. Chronic stress, which may keep your cortisol level elevated, can increase food cravings and has been linked to weight gain and obesity. Higher levels of cortisol, chronic stress, and insulin may be associated with greater future weight gain.

Despite this, some companies claim cortisol blockers can assist in weight loss.

In some cases, the U.S. government has stepped in to try to end the claims. In 2004, the Federal Trade Commission (FTC) filed suit against the marketers of CortiSlim and CortiStress. These products that claimed to aid weight loss by controlling cortisol.

You may want to talk with a doctor before taking any dietary supplements that make weight loss claims.

For healthy weight management, the Centers for Disease Control and Prevention (CDC) recommends a balanced diet combined with regular exercise.

If you aim to lose weight, it can be helpful to think about making lifestyle changes rather than following short-term diets. These lifestyle changes may include:

  • getting regular exercise
  • eating a variety of fruits and vegetables
  • choosing whole grain products over refined grain products
  • avoiding highly processed foods
  • avoiding sugary drinks

Blood, urine, or saliva tests can determine your cortisol level. A doctor may recommend taking multiple tests at different times of the day, as your cortisol levels fluctuate.

If you are concerned about your hormone levels, consider talking with a doctor about getting a cortisol test.

From there, a doctor can help support effective measures toward balancing your hormones and losing weight.

Research does not show a clear link between cortisol levels and weight loss. The FDA has taken legislative action against some companies for selling supplements and other products that they claim support weight loss by lowering cortisol levels.

Consistently high cortisol levels can be a sign of an underlying medical condition. Testing can help determine your cortisol levels.