Magnesium Products

By Herbert C. Mansmann Jr., M.D. and Shawna Kopchu RN

Choose the Right Magnesium

Choosing the right magnesium salt to take can be confusing. Each person has their own personal preference as to what they use based on manufacturer, price, quantity, dosage, ect. This page will help you understand each product based on dose, absorption rate, peak effect and side effects, ect. All of these products are considered dietary supplements and are available over the counter without a prescription. You can order all of them online or purchase them in any drugstore.

The main thing to look for when buying your magnesium is whether it is gluconate, lactate, chloride or oxide. Just going to the store and picking up a product that says magnesium on the bottle is not good enough. You need to read the label and find out what type of magnesium it is (oxide, ect) and what the dosage is.

For example if you suffer from migraines you want to use a product daily that will help increase your intracellular levels of magnesium. You would then choose one of the long acting salts like Mg Oxide or Mag Tab Sr. While taking your daily maintenance dose you may develop a headache. According to Dr Mansmann if you are having acute symptoms magnesium gluconate would be the product of choice for an acute episode. The rate of absorption is the quickest (1hr) but is also has a short duration. For that reason you would continue to take your maintenance dose but would add the gluconate to relieve acute symptoms. Upping your maintenance dose would also be an option but would not give you immediate relief of your symptoms. The following table illustrates some of the characteristics of various magnesium salts available and listed in the Physicians Desk Reference, a recognized source for doctors. Note that the table lists the organic salts separately from the inorganic salts, this is because the absorption depends on the dissociation of the Mg ion from its carrier, the rest of the salt molecule.

Product Table

Release Characteristics

Immediately Available Salts

Intermediately Available Salts

Sustained Released Salts

When Absorbed

1 hour

4-6 hours

Slowly over 12 hours

Peak Affect

1-2 hours

4-6 hours


Dosing Interval

Every 1-12 hours

Every 4-6 hours

Every 4-12 hours


Salt Name

Magnesium Gluconate (27mg) (Magonate?)


Magnesium Lactate (84mg) (Mag Tab SR?)


Salt Name


Mg Oxide (241.3mg)

Mag Oxide (400 Tab)

Magnesium Chloride (64mg) (Slow Mag?)

Salt Name


Mag Oxide (140mg) (Uro Mag Cap?)


Salt Name


Mag Oxide (250mg) (Magnesium 250 Tab?)


Salt Name


Mag Oxide (500mg) (Magnesium Cap 500?)


Magnesium Gluconate (Magonate?)

  1. This product, Magonate, is well tolerated, which is very important when taking any Mg product. Your druggist will usually have to order it, it takes only one day and does not require a prescription. Order 3 bottles of 100 tablets, enough for 2-3 months, a minimum trial. Each 500mg tablet contains 27mg of Mg, so 4 tablets equal 108mg of magnesium.
  2. Mg Oxide produces 2 time and Mg Chloride produces 3 times the incident of diarrhea, than from an equal dose of Mg gluconate.
  3. Magonate is very rapidly absorbed, and the peak effect occurs in one hour when taken on an empty stomach. This Mg salt enters the blood and the the cells, through glucose pathway. This salt then dissociates in the cells to free gluconate and functional free ionized Mg.
  4. All of the other Mg salts take up to 6 hours to peak in the blood and must be taken with a meal to minimize the occurrence of diarrhea.
  5. The idea is to slowly increase the dose up to the point of producing soft bowel movements, without diarrhea.
  6. Magonate is best taken at bedtime, and results in a sound sleep, because of muscular relaxation.
  7. Five tablets often relieve sudden unexpected acute symptoms and can be repeated as soon as one hour later without resulting in diarrhea. (Example: Take when you have a migraine, leg cramps, ect. Take in addition to your normal maintenance dose of magnesium)

Dosing with Magonate

  1. Magonate is best taken on an empty stomach, one hour before or two hours after food. Start by taking 2 at bedtime, 2 at mid afternoon. Increase the dose every 1 or 2 days, taking as much as 2 times more at bedtime than at other times.
  2. Once you reach a dose of 5 plus 5 tablets (10 tablets x 27mg = 270mg/day) I suggest adding a dose before breakfast time (mid-morning may be used, but avoid foods as above). I suggest no more than a dosing every 4-6 hours, but only 4 doses per day. Some take as much as 10 tablets twice a day.
  3. Since 10 tablets equal one Mg Oxide tablet, many have elected to switch to another magnesium salt, but you must be careful to take these other salts with food, and you must avoid diarrhea.
  4. Because of Magonates rapid onset of effects, it can be taken with another Mg salt, as stated above for unexpected acute symptoms.

Mg Oxide

  1. The recommended starting dose of Mg Oxide is 400-840mg daily. Increase your dose every 1-2 days using the above guidelines.
  2. Mg oxide has a higher incident of GI upset and diarrhea.
  3. Mg Oxide is a poor supplement due to its low bioavailability. (Tansy MF: Mag Bull 1981; 1a; 56-66)

Mag Tab SR

  1. Mag Tab SR is the only 12 hour continuous release magnesium supplement.
  2. Mag Tab SR offers more bioavailable magnesium, per dose, than any other formulation.
  3. Controlled release helps minimize GI side effects.
  4. Always start with the lowest dose and gradually increase it every 2-3 days.
  5. Mag Tab SR is the only lactate product available, so on this one you have to buy the brand name.
  6. Six to eight tablets should be taken daily for severe magnesium deficiency. Two to four tablets may be sufficient for mild, asymptomatic patients.
  7. Scored tablets may be broken without affecting the 12 hour sustained release.
  8. Convenient 12 hour dosing regimen increases compliance and response
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