Magnesium Supplementation Dosing

What if Magnesium does not meet all of your expectations

Remember Mg does not cure everything, for example if migraine control is not perfect, accept the degree of help Mg gives and move back to retrying other drugs that may not have work before for your migraine. Although there is no proof yet, it is very possible that they will work better and at a lower dose when a patient is in PMgB than when one is in NMgB. This has been proven true for other drugs, because Mg is essential for over 300 intracellular enzymes which control how drugs function. Remember the importance of Mg in the prevention of osteoporosis.


1. The Mg in the blood vessels of the intestines rigidly control the amount of Mg absorbed. Thus any overdosing with Mg causes diarrhea, which expels that specific overdose and even the dose from before, but not a later dose if the dose has been reduced. This is the way Milk of Magnesia works, resulting in evacuation of the entire bowel. Since this salt is virtually insoluble and the Mg combines with 300 times it’s weight of water, it acts as a laxative in expanding the stool mass. MgO produces 3 times and Mg Chloride, Mg is just 12% of the MgCl salt and bound to 6 molecules of water, produces 2 times the incident of diarrhea, than from an equal dose of Mg in MgG. (Mg Bull.1993; 15:10-12).

2. In the kidneys Mg is first excreted and then reabsorbed to the patient’s predetermined normal Mg serum level. As long as the kidneys are functioning adequately, the body cannot accumulate excess Mg in the blood. Kidney function is best determined by doing a serum creatinine level. Those with a creatinine level higher than normal need to be evaluated medically and dosing needs to be monitored with sMg levels, initially every week, since in this case the levels may get dangerously high. This is very extremely unlikely and we have not seen this in our twelve-year experience. We do not do this test on most patients with MgD,

3. These two responses of the body, limited absorption and limited kidney reabsorption, really protect Mg takers. In conclusion oral Mg supplementation is very safe.

4. Intravenous, intramuscular and rectal Mg can lead to toxic levels, especially if the kidney function is decreased, this is the part of MgD therapy that most physicians remember from medical training, but oral Mg is very safe if the serum creatinine is normal, best test of kidney disfunction. The GI absorption is limited if serum level is normal, as is the kidney tubular Mg reabsorption. Both are safety valves.


LEVEL in mg/dl (mEq) EFFECT
1.8 – 2.6 (1.3 – 2.1) Normal
3.4 – 6.0 (3.0 – 5.0) Hypotension
7.2 (6.0) Decrease Deep Tendon Reflexses
12 (10.0) Respiratory Paralysis
18 (15.0) Cardiac Arrest

LAXATIVE EFFECT—Goodman and Gilman list the laxative effect of magnesium as 5 gram of MgS04 or 480 mg Mg. Magonate (Fleming and Co.) tablets and liquid produces a laxative effect when given in higher doses than recommended. Mg ions bind 300 times it weight of water.

EQUIVALENT CONCENTRATIONS OF Mg, 1 mM/L equals, 2 mEq/L, equals 2.4 mg/dl, equals 24 mg/L.


Taking THE MAXIMUM TOLERATED DOSE of Mg is the SINGLE MOST IMPORTANT sign to gauge Mg therapy since it is used to determine when you are getting enough Mg just short of causing diarrhea. The Mg dose to result in this sign is called. You must measure this day in and day out to be sure you are getting as much as necessary to prevent symptoms and/or as much as possible. If one does not demonstrate this finding in one’s self, you just do not know if you are getting an adequate amount of Mg. If this important sign is present and symptoms remain unchanged for two months or so, then your doctor should order tests for serum and red blood cell Mg. If either is low the symptoms will likely improve over a longer time. But if they are normal, you then know additional Mg will unlikely improve your underlying symptoms or disease, even though one may need this amount of Mg to remain in PMgB, and have a better quality of life.

It is my belief that many medicines, in order to be effective, require the patient to be in PMgB for the medicine to work. Thus it is important to maintain PMgB by constantly seeing this sign, by the personal observation of one’s self every day. Remember any degree of constipation is one of the most important clinical symptoms of Mg deficiency.

THE Best test to evaluate a child’s compliance or to know if one is getting enough oral magnesium is the presence of SOFT, SEMI-FORMED BOWEL MOVEMENTS daily. Observe bowel movements several days a week. They should be soft and semi-formed, which usually fall apart in the toilet water and some parts often float, while the water remains clear and colorless. Once the water in the toilet bowl becomes colored and/or cloudy, this meaning that one is having diarrhea, because there is an excess of magnesium in the bowel content. Mg expands the size of the stool by binding water and thus adding 300 times the weight of Mg to the food waste bulk of the bowel movement. This unabsorbed water softens the stool. The point of Mg therapy is to get just sufficient Mg to produce soft, semi-formed stools without diarrhea. If one over shoots the dose then one needs to cut back about 10-20% on every dose until there are soft, semi-formed stools and the water in the bowl remains clear and colorless. There will also occur an increased frequency of bowel movements to 2-3 times a day; this is good and nothing to worry about. You have just gone from hard dry, infrequent movements, to soft, wet, semi-formed stools.


Some patients have trouble taking even their RDA for Mg, much less that needed for all symptoms of MgD. The following methods have enabled some, with erythromelalgia and/or diabetic neuropathy, to take a higher dose and still cope with Mg induced diarrhea (MgID).

1. Both Magonate and Mg Oxide can be crushed, in a pill crusher or in a Waring blender, mixed with water and sipped every hour or so, or added to food before or after cooking. Some have reached 6-10,000 mg/day, using these methods. These salts are tasteless. Do not crush Mag-tab SR, but Maginex and Slo-Mag may be tried, but Slo-Mag is an enteric-coated pill containing Mg chloride that opens after the stomach.

2. We have also seen some patients that tolerate a different Brand of these first two salts, because the included ingredients (fillers) are different.

3. Fiber is often considered useful to control loose bowel movements. Psyllium containing mixtures bind Mg in the bowel, thereby requiring an increased Mg dose. We have tested calcium polycarbophil, FiberCon, and it does not bind Mg. A new soluble fiber, UniFiber, from Niche (see Mag-Tab SR above) has proven to be very well tolerated and their claim that it does not bind medicines and minerals seems true. It is tasteless and suspends in many juices, only just increasing it’s thickness.

4. Those with chronic diarrhea or a sensitive stomach associated with many intestional diseases such as Crohn’s disease, Irritable Bowel Syndrome and Ulcerative Collitis, to name a few, receive significant benefit from Imodium A-D, or if more gaseous discomfort Imodium Advanced (both OTC). They have proven very helpful. Initially follow the instructions on the box, and continuing with the lowest effective dose. A dose of 0.08-0.24 mg/kg/day divided 2-3 times/day, with a maximum of 2 mg/dose has been recommended for chronic diarrhea.

5. Since about 80% of fecal mass is bacteria, effort to reestablish bacterial content should be tried by adding Probiotics, various brands of Lactobacillus Acidophilus. The theory is that since many bacteria can adapt to their environment and survive antibiotics that certainly some might live in Mg soup. The final verdict is still out.

6. Apple Pectin (GNC) should be tried.

Those with MgID need to have their physician involved and have their serum electrolytes checked monthly, to assure yourself and you physician that MgID has no significant long term acid-base problems. (Personal experience using these methods showed normal serum electrolytes over two years, while taking 8,000 16,000 mg of elemental Mg /day).


1. As long as the causes are present, extra Mg will be necessary. Therefore one must constantly work on changing ones life style. Many will need to evaluate their drugs for urinary Mg wasting and reduce the amount or change medications.

2. MgD is a dynamic process and subject to your daily “life style behaviors”. Some of the causes, which you know may be modified (example; exercise for 20 min 3x a week helps stress). Also see the following document on our web site: “Assuming Responsibility for the Management of Your Stress by Learning Coping Skills.” You will have to reassess your need for the current Mg dose, by slowly reducing the dose every few months. However, most patients need Mg for years usually at lower maintenance doses.

3. Everyone must assume that they need more Mg than the American diet provides. Moreover, being in PMgB rather than being symptomatic in NMgB is healthier. Over time the NMgB can only get worse, because each day insufficient Mg is taken by mouth and additional bone reserves are depleted.

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