Magnesium (serum)

What Is It?

Magnesium is a mineral which is essential for several bodily functions including energy production, the function of nerves, muscle contraction and maintaining strong bones. We acquire magnesium through our diet where it can be absorbed through the small intestine and colon. In plants, magnesium is found in chlorophyll and so is abundant in green leafy vegetables.[1]

Which tests include this marker?

What Role/s Does the Biomarker Have in The Body?

Over 300 biochemical reactions in the body require magnesium. Therefore, it is essential that we acquire enough from our diet to ensure these functions can be carried out efficiently. Almost all the magnesium in the body (99%) is found in the bones, muscles or tissue. Magnesium is known to stabilise many enzymes, particularly in energy-producing reactions. Energy is needed for many functions including the use of glucose, the production of fats, proteins and nucleic acids and for muscle contraction. If the metabolism of magnesium is disrupted, then this can affect the functions associated with energy.[2]

Magnesium is essential for the existence of human beings. However, as the popularity of refined foods increases, there is speculation that magnesium deficiency could also rise. Changes in magnesium levels occur slowly over a period of months and sometimes years. Whereas, too much magnesium in the body usually results from over supplementation.

How Does the Biomarker Affect My Wellbeing?

Magnesium is required for lots of functions within the body. However, magnesium deficiency occurs when not enough is being taken in through the diet, there are underlying health conditions or if medications are being taken which increase the excretion of it.[3] Symptoms of magnesium deficiency can include:

  • Weakness
  • Tremor
  • Nausea
  • Vomiting
  • Fatigue
  • Irregular heartbeat
  • Seizures

When magnesium is low in the body this can also influence calcium levels because magnesium is required by enzymes that regulate calcium.[4] As a result magnesium deficiency can exacerbate calcium deficiency. 

Usually, high magnesium levels from the diet are dealt with by the body and excreted by the kidneys. However, excessive magnesium supplementation can cause diarrhoea, nausea and stomach cramps.[5]

How Can I Improve My Result?

Magnesium levels can affect other mineral levels in the body including calcium and potassium. Therefore, it is essential that our intake of magnesium is adequate and from good dietary sources.


Magnesium can be acquired from the diet. Good sources are:

  • Green leafy vegetables e.g. spinach
  • Nuts
  • Edamame beans
  • Avocado
  • Broccoli
  • Fish
  • Rice
  • Dried beans and legumes

Some studies have found a link between low magnesium levels and depression, particularly in young adults.[6]

Mineral and some bottled waters contain magnesium, but the amount depends on the size of the bottle and the brand.


Exercise has a beneficial impact on the gut environment and the diversity of the microbes which live in it.[7] Therefore, exercise is an important aspect of a healthy lifestyle and could aid with the normal functions within the body. 

Everyone should aim for at least 150 minutes of aerobic exercise per week, carried out over a period of 5 days. Activities can include walking, jogging, swimming and cycling.

Tests that include this marker


Is your diet supplying you with all the micronutrients your body needs? This nutrition test will identify any deficiencies.


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[1] The Open University. (2017). Nutrition: Vitamins and Minerals. The Open University.

[2] Jahnen-Dechent, W and Ketteler, M. (2012). Magnesium Basics. Clin Kidney J: 5(Suppl 1), pp 13-14.

[3] NHS Dorset Clinical Commissioning Group. (2014). The Management of Hypomagnesaemia in Primary Care. Available at:

[4] GrÓ§ber, U., Schmidt, J and Kisters, K. (2015). Magnesium in Prevention and Therapy. Nutrition: 7(9), pp 8199-8226.

[5] National Institutes of Health. (2018). Magnesium. Available at:

[6] Tarleton, E, K and Littenberg, B. (2015). Magnesium Intake and Depression in Adults. Journal of the American Board of Family Medicine: 28(2), pp 249-256.

[7] Clarke, S, F., Murphy, E, F and O’Sullivan, O et al. (2014). Exercise and Associated Dietary Extremes Impact on Gut Microbial Diversity. Gut: 63, pp 1913-1920.

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