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What magnesium is best for high cortisol?
Magnesium glycinate at 300mg elemental is the magnesium to take if you think cortisol is high, not a treatment. High cortisol in lifters usually means poor sleep, overtraining or a long deficit; genuinely high cortisol is a GP matter.
- 300mgelemental per 2 capsules of glycinate
- Sleep, load, caloriesthe three things that raise a lifter's cortisol
- 0authorised cortisol claims for any magnesium
- 22pa day for the worked example
Worked example: Futuro Labs Magnesium Glycinate on Amazon UK, 300mg elemental per serving, £19.99 for 90 days. Label breakdown. The trial evidence is on the which magnesium reduces cortisol page.
What high cortisol usually means for someone who trains
Cortisol rises every morning, rises with every hard session and rises when you sleep badly, diet hard or stack stress on top of a training block. That is a normal rhythm doing its job, not a disease, and it is what most lifters mean when they say their cortisol is high: tired but wired, waking at 4am, holding fat around the middle, flat sessions. The levers for that are sleep, training load and calories, in that order. Genuinely high cortisol, the medical kind, is rare and comes with signs a GP recognises: rapid weight gain in the face and trunk, purple stretch marks, easy bruising, high blood pressure, muscle weakness in the thighs. If that list sounds like you, it is a GP appointment, not a supplement page.
Where magnesium fits
Pickering's 2020 review describes the loop: stress raises magnesium losses in urine, low magnesium raises the stress response. Golf's studies of athletes under extreme physical load in the 1990s reported that magnesium supplementation blunted the stress hormone rise during hard training. Boyle's 2017 review found the effect on subjective stress suggestive and low quality. The authorised claims stop at normal psychological function and the normal functioning of the nervous system. So magnesium's role in high cortisol is to stop a low intake making a normal stress response worse; nothing more, and no product can claim more.
| Form | Elemental magnesium | Evening tolerance at 300mg | Cortisol evidence | Verdict |
|---|---|---|---|---|
| Glycinate (bisglycinate) | about 14% to 20% | Best | General magnesium studies in athletes | The form to take |
| Taurate | about 9% | Good | None specific | Three or four capsules for the same dose |
| L-threonate | about 8% | Good | None; animal brain data | Most expensive for the least magnesium |
| Citrate | about 16% | Laxative | General studies | Morning only |
| Adrenal or stress blends | often oxide, unprinted | Varies | None | Skip |
Dose, timing and the worked example
Two capsules of Futuro Labs Magnesium Glycinate with the evening meal: 1500mg chelated bisglycinate at 20%, 300mg elemental, 80% NRV, low laxative effect, vegan capsule, made in the UK under GMP and BRC certification, third-party tested for heavy metals and microbiology, 180 capsules for £19.99, 22p a day. Alongside it, the things that actually move a lifter's cortisol: seven or more hours of sleep, a deload if the block has run long, and calories back to maintenance if the cut has run longer than twelve weeks. Judge sleep quality after a month. If you take medication, the label says to check with a pharmacist first.
What to check on the label
- Elemental magnesium 300mg per serving, 80% NRV printed.
- Glycinate first; not an adrenal blend with the magnesium form unprinted.
- No cortisol, adrenal or stress claims; none are authorised.
- Nothing you did not choose: ashwagandha and other adaptogens have their own cautions.
- Cost per day under 25p.
The worked example: Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the worked example: 300mg elemental per 2 capsules (80% NRV) from chelated bisglycinate, tolerated nightly, vegan, UK made, third-party tested, 22p a day from a £19.99 bottle of 180. Taken to stop a low intake making training stress worse, not to treat cortisol.
- Elemental magnesium per serving
- 300mg (80% NRV)
- Form
- magnesium bisglycinate 20%
- Serving
- 2 capsules a day
- Bottle
- 180 capsules, 90 days
- Price
- £19.99 (22p a day)
- Capsule
- vegetarian shell, vegan product
Questions people also ask
Which magnesium is best for high cortisol levels?
Glycinate at 300mg elemental with the evening meal. Futuro Labs Magnesium Glycinate: 300mg elemental, 22p a day. No form treats high cortisol.
Does magnesium lower cortisol?
Small studies in athletes under heavy load reported a blunted stress hormone response with supplementation. No trial in ordinary adults shows lower cortisol and no claim is authorised.
How do I know if my cortisol is high?
Poor sleep, fatigue and flat training are a normal stress response, not a diagnosis. Rapid weight gain in the face and trunk, purple stretch marks, easy bruising and high blood pressure are GP territory.
What is the best time to take magnesium for cortisol?
With the evening meal, because sleep is where a stress problem shows and where the magnesium evidence is strongest.
Should I take magnesium and ashwagandha for cortisol?
Ask a pharmacist first, especially with any medication or a thyroid condition. Ashwagandha has its own evidence and its own cautions.
Sources
- Futuro Labs Magnesium Glycinate listing, Amazon UK, label and price checked 31 August 2026. https://www.amazon.co.uk/dp/B0BT7Z5VQW
- Pickering G, et al. Magnesium status and stress: the vicious circle concept revisited. Nutrients 2020;12(12):3672. PubMed record
- Golf SW, Bender S, Grüttner J. On the significance of magnesium in extreme physical stress. Cardiovascular Drugs and Therapy 1998;12(Suppl 2):197-202. PubMed record
- Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress, a systematic review. Nutrients 2017;9(5):429. PubMed record
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to magnesium. EFSA Journal 2010;8(10):1807. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2010.1807
- Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf