Cortisol: What It Is and How It Impacts Your Health

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Cortisol is your body’s main stress hormone. It works with parts of your brain to control your mood, motivation, and fear. It’s made in your adrenal glands—little orange triangle-shaped organs that sit on top of each of your kidneys like a hat. Cortisol is best known for fueling your body’s fight-or-flight response, but because most of our cells have cortisol receptors, it plays an important role in many body functions.

  • Reduces inflammation
  • Regulates blood pressure
  • Controls blood sugar levels
  • Regulates metabolism
  • Influences immune function
  • Assists with memory formation
  • Controls your sleep/wake cycle
  • Regulates energy levels

The secretion of cortisol is controlled by a complex series of interactions between the hypothalamus in the brain, the pituitary gland, and the adrenal glands—often referred to as the HPA axis. This axis depends on a continual cycle of feedback to regulate the functions above based on what the body needs at any given time. But excessive stress—physical or perceived—can disrupt the HPA axis and cause overproduction of cortisol, which can have widespread negative effects on your body.

High Cortisol Levels

When cortisol is elevated over long periods of time, it can cause a variety of health problems:

  • Chronic illnesses: high blood pressure, diabetes, and heart disease
  • Compromised immune health
  • Weight gain
  • Fatigue
  • Brain fog and reduced memory and focus
  • Increased inflammation
  • Accelerated aging
  • Digestion issues
  • Mood disorders (depression and anxiety)
  • Sleep problems

How Cortisol Impacts Your Sleep

Cortisol plays a huge role in the sleep-wake cycle. It’s secreted continually in a 24-hour rhythm. In a healthy state, your cortisol starts to rise after midnight, increasing rapidly around the time you wake up and usually peaking around 9 a.m. This early rise helps stimulate wakefulness in the morning and helps you maintain alertness throughout the day.

Cortisol then starts a gradual decline, tapering slowly and reaching its lowest level in the evening. Melatonin levels rise, and you start to feel sleepy and ready for bed. The lowest cortisol point is typically around midnight when you ideally should be asleep.

This is the ideal rhythm, but spikes in cortisol levels from chronic stress can throw this cycle off. Poor, insufficient, irregular sleep increases cortisol levels, leading to even more stress and, over time, the health complications I mentioned earlier. To make matters worse, a more active HPA axis can interfere with your body’s ability to maintain consistent high-quality sleep. So, it turns into a vicious cycle.

Calm Your HPA Axis & Improve Your Sleep

The good news is that you can help balance your HPA axis and lower cortisol levels with simple lifestyle changes. Give these recommendations a try so you can enjoy a restful, solid night’s sleep again.

  • Light to moderate exercise (intense exercise can elevate cortisol)
  • Yoga
  • Tai Chi
  • Breathing exercises
  • Progressive muscle relaxation
  • Mindfulness-based stress reduction

I’ve also found it helpful for my clients who struggle with middle-of-the-night waking to avoid alcohol, sugar, and refined carbohydrate snacks before bed. All three can cause a spike in your blood sugar that will inevitably dip throughout the night, triggering a cortisol response that wakes you up.

Instead have a small snack with complex carbohydrates, protein, and fat to keep your blood sugar stable throughout the night. In our family, sliced apples with nut butter is a favorite!

5 Supplements to Help Balance the HPA Axis

1. Ashwagandha: An adaptogen that has been shown in clinical studies to reduce stress. Suggested dose: 250 mg daily.

2. L-theanine: An amino acid known to promote relaxation and stress reduction. Suggested dose: 250 mg daily.

3. Magnolia: A Chinese herb that has been used for centuries as a natural calming agent. The bark of the magnolia plant contains several substances that help reduce stress and anxiety. Suggested dose: It’s best to discuss the appropriate dosage with your health care provider.

4. Epimedium: A traditional Chinese medicinal herb that has been used to relieve general fatigue and stress. Suggested dose: The appropriate dose depends on several factors including age and health conditions. I recommend discussing with your health care provider.

5. Phosphatidylserine: A fatty substance produced in the body that protects every cell has been shown to reduce cortisol levels and promote a positive mood, by decreasing feelings of stress. Suggested dose: Dosages used in studies range from 60–800 mg per day.

For additional information, I recommend speaking with your health care provider. You can request a salivary cortisol curve test. It determines if you have high cortisol levels at night. Plus, it can help you see where your cortisol levels fall throughout the day compared to the normal cortisol curve.


Dr. Briana Sinatra

Meet Dr. Briana Sinatra

Dr. Briana Sinatra is a board-certified naturopathic doctor with a vibrant practice in the Pacific Northwest. There she focuses on women’s and family health, taking a holistic approach to healthcare by empowering women with the knowledge and tools they need to live their best life now and protect their future wellness by looking at how all the systems in the body work together and how diet, lifestyle, and environment all influence health.

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