How to Lower Cortisol: What the Evidence Supports

Cortisol is a hormone your adrenal glands make, and it is meant to rise in the morning and fall at night. In trials, exercise and meditation programmes lowered it modestly, caffeine raised it in people not used to it, and ashwagandha lowered it in small trials. No study has shown that a lower reading improves health in healthy people.

Evidence at a glance

• Trials: eight pooled analyses of 10 to 46 studies each: exercise, meditation, yoga, lost sleep, fasting, live cultures and ashwagandha.
• Largest single trial: 141 adults with moderate stress, two ashwagandha extracts against placebo, 8 weeks.
• Strongest measured outcome: physical-activity programmes lowered cortisol across 10 studies (standardised mean difference -0.37), rated moderate certainty by the review.
• Not tested: whether lowering cortisol in healthy people improves any health outcome.

Sources checked on 13 October 2026.

What is cortisol, and what does high cortisol feel like?

Cortisol is a steroid hormone made by the adrenal glands, which sit above the kidneys, and researchers use it as a key marker of stress.¹ It follows a daily rhythm, rising sharply soon after waking and falling through the day; tired but wired explains the morning rise.

Cortisol high enough to be a disease is Cushing's syndrome, which the NHS calls "a rare condition caused by having too much of a hormone called cortisol".² Its commonest cause is long-term, high-dose steroid medicine, and it is much more common in women. The NHS lists extra fat on the neck, upper back, chest and tummy with thinner arms and legs, a red, round face, easy bruising, stretch marks, weak upper arms and thighs, mood changes and irregular periods.² A stressful month is not Cushing's.

What lowers cortisol, according to trials?

Activity, meditation and yoga programmes lowered cortisol in pooled trials; one lost night of sleep made no clear difference; fasting and caffeine raised it. No trial here tested a quick fix, and nothing needs "flushing": in the caffeine trial, each rise faded by evening.³ The habits apply to everyone, although the physical-activity trials were mostly in women.

Eggs and bananas, the foods most named online, have no pooled cortisol evidence (PubMed, 13 October 2026). The NHS stress busters start with being active and connecting with people, and say "Do not rely on alcohol, smoking and caffeine as your ways of coping".⁹ Sleep evidence is in the Wellgard sleep guide.

Do supplements lower cortisol?

No food supplement in Great Britain may claim to lower cortisol: no authorised health claim mentions it.¹⁰ What trials found for the ones people ask about most:

• Ashwagandha. Across 23 pooled randomised trials of 1,706 adults, cortisol was lower than on placebo (standardised mean difference -1.18), with results varying between trials.¹¹ A 2023 review of nine trials found lower cortisol; none looked at adrenal function or long-term effects.¹² The most-quoted trial, 64 stressed adults over 60 days, on an extract its manufacturer supplied, lowered serum cortisol more than placebo.¹³ In the 141-adult trial cortisol fell in every group, placebo included;¹⁴ a 12-week trial found no difference from placebo in perceived stress,¹⁵ and a 30-day trial found no group difference in stress scores.¹⁶ It must not be taken in pregnancy or while breastfeeding (who should not take ashwagandha). The detail is in the Wellgard ashwagandha guide; anxiety and memory results are in what ashwagandha does for the brain.
• Live cultures. Across 46 randomised trials of 3,516 people, cortisol was lower than in the control groups, a result the review rated low certainty.¹⁷
• Magnesium. One small analysis, made after a 24-week trial of 49 overweight adults and part-funded by a magnesium producer, found lower 24-hour urine cortisol on magnesium than on placebo.¹⁸

No trial has compared these with each other or with exercise on cortisol (PubMed, 13 October 2026), so none can be ranked. Combinations are covered in what can you take with ashwagandha.

What is "cortisol belly", and can you get rid of it?

"Cortisol belly" is a social-media term, not a diagnosis. Belly fat has many causes, and a waistline is not a cortisol test. The pattern the NHS links to too much cortisol is more specific: fat on the neck, upper back, chest and tummy with thin arms and legs, plus the other signs above.² No food supplement may claim to shift it. With no definition, it has never been a trial outcome; the ashwagandha trials measured cortisol, stress scores and, in a few, body weight, reported in the Wellgard ashwagandha guide. If the NHS pattern sounds familiar, see a GP.

Should you test your cortisol at home?

Cortisol tests diagnose disease. If a GP suspects Cushing's syndrome, they can arrange a blood, urine or saliva test, and a high result can lead to a hormone specialist.² For Addison's disease, a specialist checks blood before and after an injection.¹⁹ A reading moves with the hour, with caffeine³ and even on placebo,¹⁴ so a home result without symptoms has nothing to compare with. Taking thyroid medicine? Ashwagandha with levothyroxine covers whether to test cortisol first.

Can cortisol be too low?

Yes. In Addison's disease, a rare condition, the adrenal glands do not make enough hormones. The NHS lists extreme tiredness, darker patches of skin, loss of appetite, feeling sick, cravings for salty foods, dizziness on standing and muscle weakness.¹⁹ One UK case report describes a 37-year-old woman with very low cortisol and sodium who had been taking ashwagandha; she recovered with hospital treatment, and a single case cannot show the supplement caused it.²⁰ A lower reading is not a goal in itself.

When should you see a GP about cortisol?

See a GP if you have the Cushing's symptoms above, especially if you take steroid medicine,² or think you might have Addison's disease. The NHS says anyone with Addison's whose symptoms suddenly worsen, with a fast heart rate, severe tummy pain, vomiting, confusion or a seizure, should call 999: these can be signs of adrenal crisis.¹⁹

What we don't know

• No study has shown that lowering cortisol improves health in healthy people.
• No trial has compared a habit such as exercise with a supplement for cortisol.
• None of the nine ashwagandha trials in the 2023 review looked at adrenal function or long-term effects.¹²
• The physical-activity trials included few men and no older adults.¹

Frequently asked questions

What drink reduces cortisol?

No drink has an authorised claim to lower cortisol.¹⁰ The drink with the clearest data raises it: in a trial of 96 adults, caffeine raised cortisol after five days without it, and regular intake removed the morning rise but not the afternoon one.³

Can magnesium lower cortisol?

One small analysis, made after a trial ended, suggests it might: 49 overweight adults had lower urine cortisol after 24 weeks on magnesium than on placebo, in a study part-funded by a magnesium producer.¹⁸ Magnesium contributes to normal psychological function and to the reduction of tiredness and fatigue.¹⁰ Its sleep trials are in does magnesium help you sleep.

Which vitamin reduces cortisol?

No vitamin is authorised to lower cortisol. Pantothenic acid contributes to normal synthesis and metabolism of steroid hormones, vitamin D and some neurotransmitters, which describes its role in making hormones such as cortisol. Vitamins B6, B12 and C contribute to normal psychological function.¹⁰ No vitamin deficiency appears among the NHS causes of Cushing's syndrome.²

Is ashwagandha or L-theanine better for lowering cortisol?

No trial has compared them on cortisol (PubMed search, 13 October 2026), so neither can be ranked. Ashwagandha's cortisol results are pooled above; L-theanine's own trials are in what L-theanine does.

Sources

1. De Nys L et al. Psychoneuroendocrinology 2022. Pooled analysis of 10 studies. PubMed 35777076
2. NHS. Cushing's syndrome. Page last reviewed 19 March 2025. nhs.uk/conditions/cushings-syndrome
3. Lovallo WR et al. Psychosomatic Medicine 2005. Randomised crossover trial, 96 adults, 4 weeks; US government-funded. PubMed 16204431
4. Pascoe MC et al. Journal of Psychiatric Research 2017. Pooled analysis of 45 randomised trials. PubMed 28863392
5. Koncz A et al. Health Psychology Review 2021. Pooled analysis of randomised trials: 10 with blood, 21 with saliva samples. PubMed 32635830
6. Pascoe MC et al. Psychoneuroendocrinology 2017. Pooled analysis of 42 randomised trials. PubMed 28963884
7. Chen Y et al. Endocrine Journal 2024. Pooled analysis of 24 studies, 21 of them crossover. PubMed 38777757
8. Nakamura Y et al. Stress 2016. Pooled analysis of 13 studies, 357 people. PubMed 26586092
9. NHS. 10 stress busters. Page last reviewed 26 June 2026. nhs.uk/mental-health/self-help/guides-tools-and-activities/tips-to-reduce-stress
10. Department of Health and Social Care. GB nutrition and health claims register, 19 May 2026. gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
11. Fornalik M et al. Planta Medica 2026. Pooled analysis of 23 randomised trials, 1,706 adults. PubMed 41740946
12. Della Porta M et al. Nutrients 2023. Systematic review of 9 trials, 30 to 112 days. PubMed 38140274
13. Chandrasekhar K et al. Indian Journal of Psychological Medicine 2012. Randomised trial, 64 adults with chronic stress, 60 days; extract supplied by its manufacturer. PubMed 23439798
14. West RE et al. Journal of Medicine and Life 2026. Randomised three-arm trial, 141 adults, 8 weeks. PubMed 41815853
15. Smith SJ et al. Journal of Psychopharmacology 2023. Randomised trial, 120 adults aged 40 to 75, 12 weeks; manufacturer-funded. PubMed 37740662
16. Remenapp A et al. Journal of Ayurveda and Integrative Medicine 2022. Randomised three-arm trial, 60 adults, 30 days; funded by the extract's maker. PubMed 34838432
17. Jain M et al. Nutrients 2024. Pooled analysis of 46 randomised trials, 3,516 people. PubMed 39458560
18. Schutten JC et al. Clinical Endocrinology 2021. Post-trial analysis of a randomised trial, 49 overweight adults, 24 weeks; part-funded by a magnesium producer. PubMed 33030273
19. NHS. Addison's disease. Page last reviewed 19 September 2025. nhs.uk/conditions/addisons-disease
20. Patel M et al. British Journal of Hospital Medicine 2024. Case report, one woman. PubMed 38941978

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