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Minerals

Magnesium blood test without a GP referral

A magnesium blood test measures how much magnesium is in your blood. You do not need a referral from your GP, and you do not need to fast.

On a lab result, magnesium is often shortened to Mg. You get your value in mmol/l, with the lab's reference range next to it. Unlike a questionnaire or an online magnesium test, a magnesium blood test measures your actual blood level.

Your blood holds only a small part of all the magnesium in your body; most of it sits in your cells and bones. A normal blood value therefore does not fully rule out a magnesium deficiency. If you want the level inside the cells measured, you can choose intracellular magnesium.

Doctor's Assessment Included

Reference Ranges

See the value that applies to you:

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Your reference range
mmol/l
0,71 0,98 mmol/l
Reference ranges by group, in mmol/l
6 years and older 0,71–0,98 mmol/l
0,71 0,98
0,71 0,98 mmol/l

Source: NVKC Reference population: Dutch general-practice population (NUMBER, n = 7,574,327)

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

Check your own value

Magnesium: what this test measures

This test measures the level of magnesium in your blood serum. Since most magnesium is stored inside cells and bones, serum levels may not fully reflect total body magnesium status.

Magnesium: why this value matters

Magnesium supports heart rhythm, muscle relaxation, nerve signalling, and bone health. Deficiency is common and may be associated with muscle cramps, fatigue, and cardiovascular issues. Consult your healthcare provider for personalised advice.

Magnesium: how the blood test works

Referral
No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw
A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Which test
on its own €12,- Vegetarian · €161,- · InsideTracker Recovery · €139,- · InsideTracker Sleep · €199,- · InsideTracker Hormone Balance · €279,-
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Magnesium: when is testing worthwhile?

Testing may be recommended if you experience muscle cramps, weakness, heart palpitations, or sleep difficulties. Active individuals and those with restricted diets may benefit from regular magnesium monitoring.

Magnesium: symptoms of a high or low value

Low Levels

Symptoms of low magnesium may include muscle cramps, twitching, fatigue, weakness, irritability, sleep disturbances, and heart palpitations.

High Levels

High magnesium is uncommon in healthy individuals but may cause nausea, low blood pressure, muscle weakness, and in severe cases, breathing difficulties. It is usually related to kidney impairment or excessive supplementation.

Magnesium: what to do about an abnormal value

Male

If Low

Low magnesium may cause muscle cramps, fatigue, and heart palpitations. Consider magnesium glycinate supplementation (400 mg daily).

If High

High magnesium is rare but may indicate kidney dysfunction or excessive supplementation. Reduce supplement intake.

Female

If Low

Low magnesium may cause muscle cramps, PMS, and fatigue. Consider magnesium glycinate supplementation (300-400 mg daily).

If High

High magnesium is rare but may indicate kidney dysfunction or excessive supplementation. Reduce supplement intake.

Magnesium: lifestyle and this value

Include magnesium-rich foods such as dark leafy greens, nuts, seeds, whole grains, and dark chocolate. Reducing stress and limiting alcohol and caffeine may also support magnesium levels.

Magnesium: frequently asked questions

Why is magnesium deficiency so common?

Modern diets often lack magnesium-rich foods, and factors like stress, alcohol, and certain medications can deplete magnesium. Soil depletion has also reduced magnesium content in some crops.

Can magnesium help with sleep?

Magnesium may support relaxation and sleep quality due to its role in nervous system regulation. Consult your healthcare provider for guidance on supplementation.

Which form of magnesium is best?

Different forms have different absorption rates and uses. Your healthcare provider can recommend the most appropriate form based on your specific needs.

Magnesium: sources

  1. den Elzen WPJ, Brouwer N, Thelen MH, Le Cessie S, Haagen I-A, Cobbaert CM. NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach. Clin Chem Lab Med 2018;57(1):42-56. (retrieved 2026) doi.org

Test Products

This marker is included in the following test panels.

Medical reviewer

Medical standards

Dr. Naimi oversees the medical standards behind our content and assessments.

Medical policy
CIBG Ministerie van Volksgezondheid,
Welzijn en Sport Official BIG registration BIG 49928676701 Opens in a new tab

Magnesium

€12,-