- 01You are not lowering a number; you are getting the evening fall back
Cortisol is meant to be high in the morning and low by midnight. Stress, short sleep and late caffeine flatten that curve so cortisol stays up in the evening. A steep drop by bedtime matters more than any single reading, which is why sleep and timing do more than any food or supplement.
Cortisol comes down when the things that keep pushing it up stop: short sleep, hard training without recovery, long gaps between meals, afternoon caffeine, heavy drinking and stress that never switches off. The aim is to get back a daily rhythm in which cortisol peaks soon after waking and sinks to its lowest point around midnight. Sleep moves cortisol the most, so start there.
If a lab report flagged your cortisol as high, one number is not a reason to panic. Ask your clinician to repeat it as a morning blood test between 7 and 9 am after a normal night's sleep, and tell them about any steroid medicine or the pill. If you also have signs from the 'Get checked' column further down, ask whether a late-night saliva cortisol test makes sense. If your report flagged cortisol as low, that is a different problem with different causes; start with the morning cortisol marker page instead.
How to lower cortisol: the short answer
- 1Sleep on a fixed schedule (moves it most)After one night of partial sleep loss, evening cortisol ran 37% higher than after a normal night; after a night of no sleep, 45% higher 2. Aim for 7 or more hours with the same wake time every day.
- 2Keep most exercise conversational (large, fast effect)Exercise easy enough that you can talk in full sentences does not raise cortisol; harder work, from about 60% of your maximum aerobic capacity (VO2max), does for a few hours 3. Hard sessions are fine when they are spaced out and recovered from. If you have a heart condition or get chest pain or breathlessness on exertion, check with a doctor before hard training.
- 3Eat regular meals (moderate effect)Strict calorie counting 8 and skipping breakfast 9 both went with higher cortisol across the day. Eat breakfast with protein and fibre, and avoid running a hard calorie deficit for months.
- 4Put caffeine and alcohol on a schedule (moderate effect)After 5 days without caffeine, caffeine doses raised cortisol across the day; in people taking it daily the response was smaller but did not disappear 5. Keep caffeine to the morning and drinking light.
- 5Add one daily downshift (small but quick)A 20 to 30 minute break in a natural setting lowered salivary cortisol by about 21% per hour beyond its normal daily fall 4. Choose one practice and do it every day.
What cortisol is meant to do in a day
Cortisol is a steroid hormone made by the adrenal glands, which sit on top of the kidneys. Cortisol raises blood sugar when you need fuel, tunes the immune response and helps hold blood pressure up. Within 30 to 45 minutes of waking, cortisol jumps by roughly 50%, a surge called the cortisol awakening response, then falls through the afternoon and evening to its lowest point around midnight 7.
A stressful event adds a spike on top of that daily curve, and in a healthy system the spike clears within an hour or two. Chronic stress, short sleep and late caffeine change the shape of the whole day: the morning peak shrinks and the evening level stays higher than it should. That flattened curve is what most people mean by high cortisol, so the target is a steep fall by bedtime. A lower number at one moment of the day tells you much less.
Why a flattened curve matters
Cortisol that stays up into the evening keeps blood sugar higher and makes insulin work less well, pushes blood pressure up and throws the immune response off balance. It also favours fat storage around the middle, which is the grain of truth behind the phrase 'cortisol belly'. People differ in how hard their cortisol responds: early-life stress, body fat around the organs, sex hormones and genes all change it, so compare yourself with your own trend, not with someone else's.
Is your cortisol high from stress, or something else?
Everyday stress cortisol and true cortisol excess can share a few signs, such as weight around the middle and poor sleep. Cushing's syndrome, the medical condition of too much cortisol, adds physical changes that stress alone does not cause. The most common cause of real cortisol excess is a steroid medicine, such as prednisone tablets, steroid inhalers, joint injections or strong skin creams used for a long time.
| Fits everyday stress | Get checked by a doctor |
|---|---|
| Wired at night, tired in the morning | Wide purple stretch marks on the belly, thighs or arms |
| Cravings for sugary and fatty snacks | Bruising from minor knocks |
| Some weight gain around the middle | New high blood pressure or diabetes, especially under 40 |
| Irritability, poor focus | Weak thighs and upper arms (hard to climb stairs or stand from a chair) |
| Improves on holiday or after a few good nights | Rounder face, fat pad at the back of the neck, thin skin |
We recommend obtaining a thorough drug history to exclude excessive exogenous glucocorticoid exposure leading to iatrogenic Cushing's syndrome before conducting biochemical testing.
In plain words: before any cortisol test, a doctor should go through every steroid medicine you use, because steroid medicines are the most common cause of too much cortisol.
1. Fix sleep first
Sleep loss raises cortisol the next evening, when cortisol should be at its lowest. In Leproult and colleagues' study at the University of Chicago, healthy adults had higher evening cortisol after a short or sleepless night, and the evening fall was slower 2. The American Academy of Sleep Medicine recommends 7 or more hours a night for adults 15.
A fixed wake time anchors the morning cortisol peak, and some outdoor daylight soon after waking helps set the body clock. If you work shifts, keep the same sleep window on work and rest days where you can, and protect the main sleep block with blackout curtains.
How to lower cortisol at night
- Dim the lights and screens for the last 1 to 2 hours before bed; bright evening light delays the body clock that drives the cortisol fall.
- Have your last caffeine before noon.
- Finish large meals a few hours before bed, and keep alcohol away from bedtime.
- Try a few minutes of slow breathing in bed to bring the heart rate down.
- Get up at the same time even after a bad night, so the next evening's cortisol fall stays on time.
CalculatorSleep calculatorWork out a bedtime that fits your wake time and full sleep cycles.Work it out If you cannot fall or stay asleep most nights for weeks, see can't sleep, the sleep goal page and magnesium for sleep. Heart rate variability, the beat-to-beat change in your heart rhythm, is a useful daily read on recovery; HRV explained shows how to use it.
2. Move, but watch the intensity
Exercise intensity decides whether a workout raises cortisol. Hill and colleagues had men exercise for 30 minutes at 40%, 60% and 80% of VO2max, your maximum aerobic capacity: cortisol rose at 60% and 80%, and at 40%, an easy pace, it did not rise once the researchers corrected for fluid shifts in the blood 3. Over weeks, regular activity points the other way: a meta-analysis linked regular physical activity with lower resting cortisol and better sleep 16.
| Type of session | Effect on cortisol during and after | How to use it |
|---|---|---|
| Walking, easy cycling (you could chat the whole way) | No rise | Daily, any time, including evenings |
| Steady cardio where you can talk in sentences | Small rise at the upper end | Most of your weekly training |
| Intervals, heavy lifting (too hard to talk) | Clear rise for a few hours | 2 to 3 times a week, not on consecutive days, ideally earlier in the day |
| Long endurance sessions | Tends to climb as the session goes on | Eat before and after; take an easy day afterwards |
Find your own easy zone with the heart rate zones calculator, or estimate your VO2max. Strength training fits a lower-cortisol routine when you recover from it. Signs you are under-recovered: resting heart rate up by several beats for days, HRV lower than your usual, worse sleep, and soreness that lasts more than 2 to 3 days. When those show up, swap the next hard session for a walk.
3. Eat regularly: foods that lower cortisol, and cortisol-triggering foods to limit
Cortisol is one of the hormones the body releases to push blood sugar back up when it drops, so long gaps between meals and big sugar crashes both call it out (see blood sugar explained and hypoglycemia). Dieting hard has the same effect. In Tomiyama and colleagues' trial, women who counted calories on a restricted diet produced more cortisol and reported more stress 8. Witbracht and colleagues found that women who habitually skipped breakfast had higher cortisol across the day and higher blood pressure than breakfast eaters 9.
The practical version is three regular meals, protein and fibre at breakfast, and weight loss at a pace you can hold without feeling starved. People with insulin resistance feel blood sugar swings more, so meal timing matters more for them. If you take insulin or other blood sugar medicines, talk to your doctor before changing meal timing, fasting or cutting calories, because your risk of low blood sugar changes.
No food flushes cortisol out of the body. A handful of foods have trials behind them, but most of those trials used supplement doses far above what a normal plate delivers, so treat this table as a list of good foods with a plausible link to cortisol. The study doses are there to show the gap, not as amounts to take.
| Food | Why it may help | What the study used | Realistic serving |
|---|---|---|---|
| Oily fish (salmon, sardines, mackerel) | Omega-3 fats damp the stress response | 2.5 g omega-3 a day as capsules for 4 months; stress cortisol about 19% lower than placebo 12 | 2 portions a week; a 100 g salmon fillet carries about 2 g |
| Pumpkin seeds, leafy greens, beans | Good sources of magnesium, which helps regulate stress signalling | Mostly supplement trials, with inconsistent cortisol results | A small handful of seeds; greens at most meals |
| Citrus, peppers, kiwi | The adrenal glands hold a lot of vitamin C | High-dose vitamin C tablets in small trials | Fruit and vegetables daily; food cannot reach trial doses |
| Yogurt, kefir, other fermented foods | Gut bacteria signal to the brain's stress centres through the vagus nerve | Single probiotic strains in capsules, small trials | A daily serving if you like them |
| Dark chocolate (70% cocoa or more) | Cocoa flavanols may soften the stress response | Small trials of a daily dark chocolate portion, mixed results | A few squares, not a bar |
| Oats, whole grains, legumes | Slower sugar release means fewer crashes | No direct cortisol trial; works through steadier blood sugar | At breakfast, paired with protein |
If you are thinking about capsules at trial doses, check with a doctor or pharmacist first, especially if you take blood thinners (omega-3) or have had kidney stones (high-dose vitamin C). The cortisol-triggering foods are mostly the ones that crash blood sugar or break sleep:
| Limit | Why | Easy swap |
|---|---|---|
| Sugary drinks and sweets on an empty stomach | Fast rise then crash in blood sugar | Have them after a meal, or swap for fruit with yogurt |
| Energy drinks | Often 150 to 300 mg caffeine in one can, plus sugar | One coffee in the morning |
| Skipping breakfast or going 6+ hours without food | Low blood sugar calls out cortisol | A protein breakfast and a planned afternoon snack |
| Heavy meals late at night | Disturbs sleep, the biggest lever | Make lunch the bigger meal |
| Several drinks most nights | Linked to higher cortisol and broken sleep | Alcohol-free weeknights |
4. Put caffeine and alcohol on a schedule
Caffeine raises cortisol, and daily use blunts the effect without removing it (see how caffeine works). In Lovallo and colleagues' study, after 5 days off caffeine, test doses raised cortisol across the day; after 5 days at 300 or 600 mg a day, the morning dose no longer raised cortisol, but an afternoon dose still did 5. Those were research doses, not amounts to aim for. The European Food Safety Authority puts up to 400 mg a day as safe for healthy adults, about four cups of brewed coffee, and 200 mg a day in pregnancy 14. People with heart rhythm problems, high blood pressure or anxiety may do better on less. Drink it in the morning, after breakfast, and stop by noon so it is cleared before the evening cortisol fall. If you like tea, L-theanine is the calming amino acid it carries alongside its caffeine.
Heavier drinking is linked to higher cortisol. In a large British cohort of civil servants, men's cortisol rose with the number of drinks they had each week, and heavy drinkers had a flatter fall in cortisol through the day than moderate drinkers 17. A nightcap helps you fall asleep and then breaks up the second half of the night, which costs you the sleep lever too.
5. A daily downshift that works
The stress practices with measured cortisol effects all switch on the parasympathetic nervous system, the rest-and-digest side that slows the heart. A meta-analysis of randomized trials found that meditation lowered cortisol, C-reactive protein (a blood marker of inflammation), blood pressure and heart rate compared with control conditions 10. Hunter and colleagues at the University of Michigan had city dwellers take a nature break of their choosing three times a week for 8 weeks; 20 to 30 minutes gave the best return 4.
| Practice | Time a day | What the evidence shows |
|---|---|---|
| Mindfulness or meditation | 10 to 20 minutes | Lower cortisol, blood pressure and heart rate in a meta-analysis of trials 10 |
| Time outdoors in green space | 20 to 30 minutes | About 21% per hour extra fall in salivary cortisol 4 |
| Slow breathing | A few minutes | Slows the heart quickly; direct cortisol data are limited |
| Time with people you trust | Whenever you can | Support from a friend blunted the cortisol rise in a lab stress test 18 |
Most of the studies used short, regular sessions, so a daily habit is the practical choice. Pick the one you will keep doing, and pair it with something you already do, such as a walk after lunch.
For women: the cycle, the pill and perimenopause
Cortisol runs a little higher in the first half of the menstrual cycle. A meta-analysis found circulating cortisol higher in the follicular phase (from your period to ovulation) than in the luteal phase (after ovulation) 11, so the common belief that cortisol peaks before a period does not hold up. Mood and sleep changes before a period come mostly from falling progesterone and estrogen.
Skipping breakfast and long-term dieting show up clearly in women's cortisol data 8 9. Evidence on intermittent fasting and cortisol in women is mixed; if a fasting window brings worse sleep, irregular cycles or constant hunger, shorten the window. In perimenopause, night sweats and broken sleep become a cortisol driver of their own, so treating the sleep problem is part of lowering cortisol. See the female hormone panel and the menopause goal page.
Supplements: a short note
Supplements come after the five levers, because none of them outweighs a week of short sleep. Ashwagandha has the most trial data: in one 60-day trial of chronically stressed adults, serum cortisol fell by about 28% on root extract against about 8% on placebo 13. The ranked list, with the evidence for each, lives on supplements for lower cortisol.
Supplements studied for cortisol
How to tell it's working: testing and reading cortisol
The test has to match the question. As our Cushing's syndrome page puts it, "A single high morning cortisol does not diagnose it, because cortisol is meant to peak in the morning and rises with stress, illness, and even the blood draw." Screening for real cortisol excess uses different tests, chosen by a doctor after steroid medicines are ruled out 1. For tracking a lifestyle change, the first two rows are the ones you will use.
| Test | When it is taken | What it is good for |
|---|---|---|
| Morning blood cortisol | About 7 to 9 am | Checking the morning peak; mainly used to look for low cortisol |
| Afternoon or evening blood cortisol | Afternoon or evening | Seeing whether cortisol falls through the day |
| Late-night saliva, 24-hour urine or overnight dexamethasone test (a steroid tablet at night that should switch your own cortisol off by morning) | Ordered by a doctor | Screening for Cushing's syndrome 1; see the Cushing's page |
For stress-driven cortisol, the markers it pushes on are often more useful to track than cortisol itself. Chronically high cortisol raises blood sugar and insulin resistance and is tied to inflammation, so fasting glucose, fasting insulin, HOMA-IR (a score of insulin resistance from fasting glucose and insulin), A1C (average blood sugar over about 3 months) and hs-CRP (high-sensitivity C-reactive protein, a low-grade inflammation marker) show whether the changes are reaching your metabolism; see inflammation markers explained.
Markers to track
Give the changes 8 to 12 weeks before retesting, take blood at the same time of day, follow how to prepare for a blood test so a rushed morning does not skew the result, and compare against your own earlier results. One result moves for many reasons; trends beat single readings explains how to read a series.
Free, no accountRead your blood testGot your cortisol, glucose and CRP back? Put the whole report in and read them side by side.Read my results
Citations
- Nieman LK, Biller BMK, Findling JW, et al. The diagnosis of Cushing's syndrome: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2008;93(5):1526-1540.
- Leproult R, Copinschi G, Buxton O, Van Cauter E. Sleep loss results in an elevation of cortisol levels the next evening. Sleep. 1997;20(10):865-870.
- Hill EE, Zack E, Battaglini C, et al. Exercise and circulating cortisol levels: the intensity threshold effect. J Endocrinol Invest. 2008;31(7):587-591.
- Hunter MR, Gillespie BW, Chen SY. Urban nature experiences reduce stress in the context of daily life based on salivary biomarkers. Front Psychol. 2019;10:722.
- Lovallo WR, Whitsett TL, al'Absi M, et al. Caffeine stimulation of cortisol secretion across the waking hours in relation to caffeine intake levels. Psychosom Med. 2005;67(5):734-739.
- Qureshi AC, Bahri A, Breen LA, et al. The influence of the route of oestrogen administration on serum levels of cortisol-binding globulin and total cortisol. Clin Endocrinol. 2007;66(5):632-635.
- Fries E, Dettenborn L, Kirschbaum C. The cortisol awakening response (CAR): facts and future directions. Int J Psychophysiol. 2009;72(1):67-73.
- Tomiyama AJ, Mann T, Vinas D, et al. Low calorie dieting increases cortisol. Psychosom Med. 2010;72(4):357-364.
- Witbracht M, Keim NL, Forester S, et al. Female breakfast skippers display a disrupted cortisol rhythm and elevated blood pressure. Physiol Behav. 2015;140:215-221.
- Pascoe MC, Thompson DR, Jenkins ZM, Ski CF. Mindfulness mediates the physiological markers of stress: systematic review and meta-analysis. J Psychiatr Res. 2017;95:156-178.
- Hamidovic A, Karapetyan K, Serdarevic F, et al. Higher circulating cortisol in the follicular vs. luteal phase of the menstrual cycle: a meta-analysis. Front Endocrinol. 2020;11:311.
- Madison AA, Belury MA, Andridge R, et al. Omega-3 supplementation and stress reactivity of cellular aging biomarkers: an ancillary substudy of a randomized, controlled trial in midlife adults. Mol Psychiatry. 2021;26:3034-3042.
- Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012;34(3):255-262.
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on the safety of caffeine. EFSA Journal. 2015;13(5):4102.
- Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015;38(6):843-844.
- De Nys L, Anderson K, Ofosu EF, et al. The effects of physical activity on cortisol and sleep: a systematic review and meta-analysis. Psychoneuroendocrinology. 2022;143:105843.
- Badrick E, Bobak M, Britton A, et al. The relationship between alcohol consumption and cortisol secretion in an aging cohort. J Clin Endocrinol Metab. 2008;93(3):750-757.
- Heinrichs M, Baumgartner T, Kirschbaum C, Ehlert U. Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress. Biol Psychiatry. 2003;54(12):1389-1398.
Educational context only, not medical advice or a diagnosis. Always discuss your results with a clinician.
