Muscle cramps, fatigue or palpitations alone do not prove magnesium deficiency. These symptoms have various possible causes. A deficiency must be assessed in the context of diet, conditions, medicines and possible losses.
What the assessment needs to consider
Serum magnesium is a commonly used laboratory measurement, but does not represent the body's entire magnesium stores. This means neither that the measurement is useless nor that a normal result confirms every self-suspected deficiency. Laboratory findings and clinical assessment belong together.
Persistent digestive problems, increased losses or certain medicines can play a role. Kidney function and other electrolytes may also be relevant to the assessment. Which investigations are needed depends on the specific situation.
Do not respond to warning signs with a tablet alone
Seizures, fainting, marked weakness or heart symptoms with chest pain or shortness of breath require prompt medical help, and immediate help for severe acute symptoms. Do not wait to see whether a magnesium supplement works.
Consider supplements and medicines together
List supplements as well as magnesium-containing medicines. Compare amounts using the declared magnesium, rather than only the weight of a compound. Increasing the amount can cause diarrhoea and is not a safe self-test for deficiency.
Extra magnesium can be problematic when kidney function is impaired. Interactions are possible with certain antibiotics and osteoporosis medicines, for example. Timing intervals must suit the specific medicine; do not change prescribed treatments yourself.
Frequently asked questions
Are symptoms enough for a diagnosis?
No. History, examination and appropriate laboratory findings must fit together.
Does a blood result fully assess the body's stores?
No. Its limitations must be considered in the medical assessment.
Further reading
Magnesium and timing of use and Comparing magnesium forms.
Source
General information, not individual diagnosis or dosage advice.
