Magnesium Dosage

November 22, 2010

Pregnancy – Magnesium

Here we will discuss how to determine our relative magnesium needs and how to get tested for intracellular magnesium. Empowered with this knowledge, you will be able to begin to restore the mineral balance so crucial to proper metabolic function.

Western medicine tests only for serum magnesium, the magnesium moving in your bloodstream, and this is not tested routinely! By the time your serum magnesium levels are low, your intracellular magnesium levels can be dangerously low, especially in heart muscle. One of the reasons serum magnesium is not routinely tested in one’s routine CBC panels is because low magnesium alone is not diagnostic for a disease. However, we know that low magnesium levels plays a crucial role creating certain disorders and in making many diseases worse.

Magnesium is nearly undetectable in your blood, ranging from 1.7-2.4mEq/litter, as opposed to its cousin, sodium, at a whopping 140mE/liter! Total body magnesium is not reflected in serum magnesium, neither is intracellular magnesium! Less than 1% of total body magnesium is found in the serum or blood plasma! Interesting to note is that most of our magnesium is stored in our brain, our heart and skeletal muscle. There has been no research confirming any correlation whatsoever between serum magnesium levels and the levels of magnesium stored in heart tissue! Now you can begin to see why serious problems can develop with chronic depletion of this essential mineral.

People with normal serum magnesium can still have depleted total body magnesium. IntraCellular Diagnostics, Inc.™, has a test called EXATEST™, that involves simply taking a scraping from the inside of one’s mouth and sending the sample to them. It tests intracellular minerals:

  • magnesium/calcium
  • phosphorus/calcium
  • potassium/magnesium
  • potassium/calcium
  • potassium/sodium
  • phosphorus/magnesium ratios and the ions
  • magnesium
  • calcium
  • potassium
  • phosphorus
  • sodium
  • chloride

Test kits can be ordered from at their online store.

With certain conditions such as chronic fatigue, many such patients may test normal on serum magnesium but have continued exhaustion until intracellular magnesium stores and its ratios with other essential minerals are replenished. Sometimes patients will only respond to magnesium injections or intra venous therapy. Other key supplements the chronic fatigue patient needs to add are B12, C, E, beta carotene, CoQ10, and d-ribose.

How much magnesium do we need?

It has been estimated that the average western world’s intake of magnesium is between 200-300mg/day with only half that absorbed! With increased environmental and food toxins needing to be removed by the body, the stress of modern life and our acidic bodies, we have an ever present need for a constant supply of magnesium. For those who like the apparent safety margin of computing their magnesium requirements, the chart below is a rough guideline for calculating one’s daily magnesium needs. The first two rows are normal daily magnesium requirements which by modern living standards from stress, the average diet, the bio-availability of magnesium in our food and our acid states should be considered low for our actual needs!


Milligrams Per kilo body weight body weight Total milligrams magnesium
8-10 70 kilo 560-700 mg
3.5-4.5 150lbs 525-675 mg
13-15 for loss factors 70 kilo 910-1050mg
13-15 for loss factors 150lbs 1950-2250mg
Maximum 15 70 kilo 1050mg
Maximum 15 150 lbs 2250mg

Using the chart above, if you weight 150 lbs and want a moderate dose of magnesium, then you multiply your weight of 150lbs times 3.5 to 4.5, giving you a total daily milligram dose of 525-675mg.

However, most of us are already deficient in magnesium from an intracellular standpoint. Many of us suffer additional conditions that induce further depletion of magnesium or have magnesium deficiency symptoms! If so, you can use the “loss factor” calculations in the table above to find out a higher range to take.

Break the doses up into 3 or 4 and take them throughout the day. Smaller and more frequent dosages have proven to increase absorption by as much as 29% when compared to taking the entire dose at once. (Heaney, RP J of Bone and Mineral Research, 5:11;1990 p. 1135-1137)

It is also helpful to take your magnesium with other supplements or with food. However, if you are taking iron supplements, magnesium interferes with the absorption of iron! You need to take iron and magnesium 2-3 hours apart from each other.

Proper dosing without testing for intracellular magnesium ratios is not possible. You cannot determine if you have sufficient intracellular magnesium based on bowel tolerance symptoms. Bowel tolerance is the term used in taking vitamin C and magnesium. Your body absorbs both vitamin C and magnesium and when it cannot absorb anymore, it purges what it cannot absorb through your bowels, the stool. To assume that once you have reached bowel tolerance you have sufficient magnesium is incorrect! If you have bad intestinal absorption or intestinal inflammation or problems with cell membrane nutrient transport, then your body may not be able to get the magnesium into the cells and you will reach bowel tolerance sooner. But remember this does not necessarily mean you have sufficient intracellular magnesium.

Determining one’s magnesium needs is not quite an exact science because stress, our diet and daily needs fluctuate. In addition, the body takes time to deliver magnesium to where it is needed in our cells and tissues. It is also good to become familiar with your body’s signs if you are unable to test for intracellular magnesium. Do you suffer constipation? If so, consider magnesium deficiency as your primary concern and build up to the maximum dose spread out during the day, even as often as every 2 hrs until you have a bowel movement and your bowel movements begin to approach normal consistency. If your bowel movements become unformed and loose, back off on your dose the next day, and monitor your dose daily in this way. Therefore, you do not have to fear becoming toxic from taking in too much magnesium.

If you have kidney disease, work with your primary care provider in determining your maximum magnesium intake. However, getting to know your body’s signs and needs for magnesium are essential. Constipation, tight neck and shoulder muscles, leg and foot cramps are all red flags to begin to take magnesium, especially upon waking in the morning and preferably with a glass of warm water. If your stools tend to be hard, then you can definitely benefit from a magnesium supplement.

Does your body feel stiff, with stiff muscles or tendons? Do you have

  • chronic inflammation
  • sugar metabolism issues
  • low energy
  • have problems with insomnia or restless sleep

Magnesium will be the first thing to balance to improve these symptoms because they are all made worse with magnesium deficiency.

Finding your proper dosage will take some time in getting to know your body and what it is currently going through. Episodes of stress, having to take medications you have not taken before, eating too many refined carbohydrates or drinking a lot of alcohol will all cause acute depletion in your magnesium, causing your daily dose requirements to vary. If you have one or several of the chronic conditions listed above, then you would be well advised to work with a medical practitioner knowledgeable in reading organic acid and mineral lab findings to interpret your body’s metabolic needs for essential minerals and to insure you are getting a proper balance of your minerals.

Be aware also that as you replenish your cellular magnesium stores, your need for l-tryptophan, melatonin, St. John’s Wort, insulin, sleep medications, anti-depressants, cholesterol lowering drugs, thyroid medication, anti-hypertensive drugs and diuretics, osteoporosis medications will change. You will need to monitor or reduce and in some cases eliminate the drugs as your body goes back into mineral balance. Always work with an experienced medical practitioner knowledgeable about testing and weaning you off of your prescription medications.

Magnesium – Energy

Please note:
Information on this site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

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Anna Manayan

Anna Manayan