How to Lower Cortisol: 10 Questions, Answered With the Studies

To lower cortisol, remove what raises it in human trials: short sleep, not eating, low-carb dieting and too much hard cardio.

Most cortisol supplements have thin evidence, and "cortisol detox" has none.

What are the symptoms of high cortisol?

The real symptoms of high cortisol are the signs of Cushing syndrome. A JAMA review lists a red, full face, easy bruising, purple stretch marks, fat in the face, the back of the neck and around the organs, high blood sugar and high blood pressure. The most frequent cause is steroid medication. Without it, there are 2 to 8 new cases per million people a year. (Reincke 2023)

A puffy face, stubborn belly fat and waking too early are how I read high stress hormones. My view, not a diagnosis. Easy bruising and purple stretch marks mean a doctor. Tired and cold is more often a slow metabolism.

What causes high cortisol?

Outside of disease and steroid drugs, four things raise it in human studies.

• Short sleep. 13 healthy men spent 2 nights with 4 hours in bed instead of 10. Evening cortisol rose 30% in blood and 200% in saliva. (Guyon 2014)
• Not eating. In a meta-analysis of 13 studies and 357 people, fasting strongly raised serum cortisol. Milder diets did not reach significance. (Nakamura 2016) But 3 weeks on 1,200 kcal a day raised total cortisol output in a trial of 121 women. (Tomiyama 2010)
• Low-carb dieting. Across 27 studies in 309 healthy men, low-carbohydrate diets raised resting cortisol for the first 3 weeks. Then it returned to baseline, but cortisol after exercise stayed elevated. (Whittaker 2022)
• Hard endurance training. 304 endurance athletes had more cortisol in their hair than 70 controls. (Skoluda 2012) In 12 trained men, 30 minutes at 60% and 80% of maximal oxygen uptake raised cortisol by 39.9% and 83.1%. At 40% it did not rise significantly. (Hill 2008)

Caffeine matters less than people think: in 48 men and 48 women, 5 days of daily intake abolished the cortisol response to the 9 AM dose, but not the afternoon one. (Lovallo 2005)

Is high cortisol in the morning normal?

Yes. In 152 children, adults and elderly people, free cortisol rose by 50 to 75% within 30 minutes of waking. (Pruessner 1997)

My view: liver glycogen runs low overnight, so cortisol rises to make glucose. So I aim for 100 g of sugar with gelatin and salt in the first hour.

The human data is thinner than my posts. On one of two lab days, 30 women who habitually skipped breakfast had higher cortisol until mid-afternoon than 35 who ate it. (Witbracht 2015) That is a comparison, not a trial.

How do you lower cortisol naturally?

Reverse the list above: sleep, eat, keep the carbohydrate, go easy on cardio. Then add:

• Relax on purpose. In a meta-analysis of 58 trials and 3,508 people, stress management lowered cortisol. Mindfulness, meditation and relaxation worked best. (Rogerson 2024)
• Breathe slowly. 40 adults were randomized to 20 sessions at 4 breaths a minute over 8 weeks, or to nothing. Cortisol fell only in the breathing group. (Ma 2017)
• Get bright light. In 20 adults, 6.7 hours at about 10,000 lux lowered plasma cortisol. (Jung 2010) But in 8 sleep-deprived men, bright light early in the morning raised cortisol by more than 50%. (Leproult 2001)

Being fair on sleep: a meta-analysis of 24 studies of acute sleep deprivation found no significant difference in cortisol overall, only in studies using serum or repeated measurements. (Chen 2024)

Does sugar lower cortisol?

Not eating raises cortisol, but sugar itself does not reliably lower it. This is where the studies disagree with me most.

• For. 19 women drank sucrose or aspartame drinks three times a day for 2 weeks. Sucrose went with a lower cortisol response to stress. The authors read that as a reason sugar is hard to quit. (Tryon 2015)
• The mechanism. In 10 healthy people whose blood glucose was lowered stepwise, cortisol secretion switched on at 58 mg/dl. (Schwartz 1987)
• Against. Healthy men fasted 8 to 11 hours, then drank 100 g of glucose or water before a stress test. After glucose the cortisol response was large. After water it was not significant. (Kirschbaum 1997) A second trial in 37 men agreed. (Gonzalez-Bono 2002)
• My own thread. I posted that 75 g of sugar dropped cortisol in 15 women. The abstract counts 16 women and does not mention a cortisol drop, only a lower cortisol to DHEAS ratio in the 8 with migraine. (Kokavec 2010) The thread and the ratio.

Which foods lower cortisol?

No single food has strong evidence. Eating enough, with enough carbohydrate, does.

• Dark chocolate. 30 people ate 40 g a day for 14 days. Urinary cortisol went down. (Martin 2009)
• Salt. I say more salt means less stress hormone. Adrenaline, noradrenaline and aldosterone did rise when sodium was cut. (Graudal 2020) Cortisol did not: in 8 healthy volunteers, a low sodium diet lowered urinary cortisol from 124 to 86 nmol a day by day 2. (Lewicka 1998)

Do cortisol supplements work?

A few moved a number in one small trial each. None is proven.

• Magnesium. 49 overweight adults took 350 mg a day or placebo for 24 weeks. 24-hour urinary cortisol fell by 32 nmol against placebo. (Schutten 2021)
• Vitamin C. 60 healthy young adults took 1000 mg three times a day for 14 days, 60 took placebo. Cortisol recovered faster after a stress test, but the overall response was not smaller. (Brody 2002)
• Vitamin D. In a preliminary trial of 15 healthy people, 9 took 2,000 IU a day for 14 days. Their urinary free cortisol fell from 162.65 to 96.4 nmol a day. (Al-Dujaili 2016)
• Fish oil. This one goes against me. 138 adults took omega-3 or placebo for 4 months. The 2.5 g a day group had 19% lower cortisol during a stress test. (Madison 2021) I still avoid it because it is PUFA. My view.

Does ashwagandha lower cortisol?

In the trials, yes. One meta-analysis of 488 people pooled 7 trials and found cortisol 1.16 µg/dL lower, with no significant change in perceived stress across 6. (Albalawi 2025) Another, of 9 trials and 558 people, found lower cortisol and lower perceived stress. (Arumugam 2024) The largest, 23 trials and 1,706 people, found lower cortisol and higher serotonin. (Fornalik 2026)

The limits: trials ran 30 to 112 days, and none checked adrenal function long term. (Della Porta 2023) One case series describes five people with liver injury and jaundice, starting 2 to 12 weeks in. (Björnsson 2020)

I am not a fan. I took it twice and threw up both times, and I list it under never choose for gut issues. In my view serotonin is a stress signal: how to lower serotonin. The trials say it lowers cortisol.

The honest part: is cortisol the enemy?

• No. Too little cortisol is adrenal insufficiency, which includes Addison's disease: fatigue, nausea, weight loss, and a crisis that can end in shock and death if untreated. (Vaidya 2025) Never stop steroid medication without your doctor.
• The morning peak is normal and healthy.
• "Cortisol detox" has no trials. PubMed does not contain the phrase. A systematic review of 58 studies found no substantiation that "adrenal fatigue" is a real medical condition. (Cadegiani 2016)
• One number says little. The rise on a single morning mostly reflects that day. It takes 2 to 6 days of sampling to be reliable. (Hellhammer 2007) Doctors confirm an abnormal Cushing test with a second one. (Nieman 2008)
• Where the studies disagree with me: sugar under stress, salt, fish oil, ashwagandha, and low-carb after 3 weeks.

So what do I do every day?

• Eat. Sugar and salt in the first hour, carbohydrate at every meal: fruit, juice, milk, honey, potatoes. No fasting, no low-carb.
• Fuel training. Carbs before, a sugary drink during.
• Sleep. 8 to 9 hours. Lost sleep also costs dopamine.
• Sun. Outside every day.
• Lift and walk. Strength training, slow walks, little hard cardio. My experience, not a trial.

People will do anything to lower cortisol except eat. The reasoning is in Ray Peat on cortisol.

Quick answers

How do you lower cortisol naturally?

The levers with human studies are sleep, eating enough, keeping carbohydrate in the diet and not overdoing hard endurance training. Two nights of 4 hours in bed raised evening cortisol in healthy men, and fasting strongly raised serum cortisol in a meta-analysis of 13 studies. Meditation, relaxation and slow breathing lowered it in trials.

What are the symptoms of high cortisol?

True cortisol excess is Cushing syndrome: a red, full face, easy bruising, purple stretch marks, fat in the face, the back of the neck and around the organs, high blood sugar and high blood pressure. It is rare and most often caused by steroid medication. These signs need a doctor.

What causes high cortisol?

Apart from Cushing syndrome and steroid drugs, human studies point to short sleep, fasting and strict dieting, the first weeks of a low-carbohydrate diet, and intensive endurance training. Caffeine raises cortisol too, but the response shrinks with daily use.

Is cortisol supposed to be high in the morning?

Yes. Free cortisol rises by 50 to 75% in the first 30 minutes after waking in healthy children, adults and elderly people. This cortisol awakening response is normal and is not a sign of disease.

Does sugar lower cortisol?

Not eating raises cortisol, and in one 2-week trial women drinking sucrose had a lower cortisol response to stress than women drinking aspartame. But in fasted men, a glucose drink made the cortisol response to a stress test larger than water did. The evidence is mixed.

Does ashwagandha lower cortisol?

In meta-analyses of randomized trials it lowered cortisol, by 1.16 µg/dL in one of them. Perceived stress did not change significantly in that analysis and improved in another. The trials lasted 30 to 112 days, long-term effects on the adrenal glands were not studied, and cases of liver injury have been reported.