How to lower cortisol: what stress does to your body and what helps

A packed diary, worries on your mind, nights when you can't settle. Stress is part of life, and a little of it even helps you get things done⁶. Too much stress, though, can take its toll on body and mind⁶. That's when many people start wondering how to lower their cortisol. This article explains what the hormone does and what studies show about everyday habits and nutrients.

What is cortisol?

Cortisol is a hormone produced by the adrenal glands, two small glands that sit on top of the kidneys¹. It acts on almost every organ in the body: it helps you respond to stress and plays a part in inflammation, blood sugar, metabolism and blood pressure¹. That's why it's often called the stress hormone¹.

Your cortisol level changes over the course of the day. It is normally highest in the morning and considerably lower by the afternoon¹. Stress and exercise make it rise too¹. So a rise when you're under pressure is part of your body's normal response.

Stress symptoms: how do you know it's too much?

Stress makes it hard to switch off. Many people become irritable or anxious and find it harder to concentrate⁶. The body reacts as well, for example with headaches or other aches and pains, stomach problems or trouble sleeping⁶. Some people eat less than usual, others more⁶.

Stress that goes on for a long time can make existing health problems worse⁶. If the strain is constantly affecting your daily life, get help, for example from your GP⁶.

Too much cortisol: when should you see a doctor?

Persistently and markedly raised cortisol levels are something quite different from everyday stress. They may point to Cushing's syndrome, a condition in which the body is exposed to too much cortisol over a long period¹. The cause is often long-term use of high-dose corticosteroids (steroid medicines), and less often a hormone-producing tumour¹. Possible signs include weight gain, a rounded face, thin arms and legs, and bruising easily¹.

Whether your cortisol is too high can only be confirmed by blood, urine or saliva tests, often taken at several times of day¹. Never stop prescribed steroid medicines on your own, because stopping suddenly also throws your hormone levels out of balance¹.

Reducing stress: what helps in everyday life

The World Health Organization (WHO) recommends some simple steps: a regular daily routine, enough sleep, keeping in touch with people you trust, a balanced diet, regular exercise and limiting how much time you spend following the news⁶. For some of these, cortisol has been measured, as the following sections show.

Sleep

In a study of healthy young men, evening cortisol after a night of severely restricted sleep was 37% higher than on the previous day, and after a night with no sleep at all it was 45% higher². Regular bedtimes, a quiet, dark bedroom and little screen time before bed are among the WHO's recommendations⁶. It's also best to avoid large meals, caffeine and alcohol in the evening⁶.

Time in nature

In one study, 36 city dwellers spent ten minutes or more in nature at least three times a week for eight weeks³. Their salivary cortisol fell by 21% per hour more than its usual daily pattern would lead you to expect³. Measured per minute spent outdoors, the effect was greatest at 20 to 30 minutes³. The group was small, however.

Meditation

For meditation, the picture is mixed. In a systematic review, blood cortisol fell more with meditation than in comparison groups, but mainly in people with a physical illness⁷. In saliva samples, the effect was small and not clear-cut⁷.

Ashwagandha and cortisol: what the studies measured

Ashwagandha (Withania somnifera) is a plant whose root is traditionally used for stress in Ayurvedic medicine⁴. In a meta-analysis of seven studies on cortisol, levels with ashwagandha were on average 1.16 µg/dl lower than with placebo⁴. For perceived stress, measured with a questionnaire, the same analysis found no clear difference⁴.

Another review of nine studies reached a similar result for cortisol⁸. The studies lasted 30 to 112 days and varied widely in the extracts and amounts used, and none of them looked at possible long-term effects⁸. You'll find the details in our article on what the studies on ashwagandha and cortisol examined.

If you're thinking of trying ashwagandha and you take any medication, get medical advice first.

Magnesium and B vitamins: nerves and mind

There is no authorised health claim for any nutrient in relation to psychological stress, but there are claims about the nerves and the mind. Magnesium contributes to normal functioning of the nervous system and to normal psychological function⁵. The same applies to vitamin B6, vitamin B12, thiamine (vitamin B1) and niacin: each contributes to normal functioning of the nervous system and to normal psychological function⁵. Magnesium and several B vitamins also contribute to a reduction of tiredness and fatigue⁵.

If you'd like to top up your magnesium intake, a magnesium supplement is one option. Do not exceed the recommended daily amount.

Melatonin: which claims are authorised?

Stress costs many people their sleep⁶. For melatonin, there is an authorised health claim relating to falling asleep: melatonin contributes to the reduction of time taken to fall asleep⁵. The beneficial effect is obtained by consuming 1 mg of melatonin close to bedtime⁵. There is no authorised claim for melatonin relating to stress or cortisol⁵.

A second claim is also authorised: melatonin contributes to the alleviation of subjective feelings of jet lag. The beneficial effect is obtained with a minimum intake of 0.5 mg to be taken close to bedtime on the first day of travel and on the following few days after arrival at the destination⁵.

Frequently asked questions about cortisol and stress