hi i looked up the product and found these details:
http://www.kiwidrug.com/gohealthynz/magnesium_800/
Ingredients per VegeCap
Magnesium aspartate (equiv. Magnesium 20mg) 100mg,
Magnesium amino acid chelate (equiv. Magnesium 20mg) 100mg,
Magnesium citrate (equiv. Magnesium 20mg) 100mg,
Magnesium oxide (equiv. Magnesium 300mg) 500mg
(TOTAL ELEMENTAL MAGNESIUM 360mg)
so, the largest part of that 360 mg you're getting is 300mg one of the least absorbable forms, unfortunately. because it is relatively insoluble you won't be able to absorb most of it. and no, i wouldn't add any more of that to your daily regimen, or you might find yourself running to the toilet too often!
see if you can find a magnesium glycinate product. that is the best absorbed form that i'm aware of.
eg:
http://www.netpharmacy.co.nz/prl-quantu ... 0-capsules
if you tell me where you are i'll see if i can find you a link to a better local deal. i pay $20 CDN for a bottle but i'll have to get back to you with the number of capsules.
also, epsom salts (magnesium sulfate) baths according to package directions could be useful.
http://en.wikipedia.org/wiki/Magnesium_sulfate
best of all, a solid boost to your intake of healthy magnesium-rich foods could help (synergies with other food nutrients are really important!)
http://whfoods.org/genpage.php?tname=nutrient&dbid=75
and last but not least, avoiding foods that deplete or interfere with magnesium could help a lot.
"Interferences from food, drugs, alcohol, hormones, other supplements (Frequent consumption of alcohol, coffee, food components ie, phytates, phosphorous, fiber, saturated fats, tannins, polyphenols can block or decrease mineral absorption. Antacids, anti-inflammatories, antibiotics, diuretics, or hormone replacement can cause considerable depletion of magnesium. Digoxin, Amiodarone and Betapace (sotalol) are known depleters of Mg.(4) High-dose calcium supplements compete as do calcium-containing antacids like Tums; consuming large quantities of caffeine and alcohol can deplete magnesium – ie, diuretic effect.)" (note a key 'other supplement' not specified is vitamin D3 - an important supplement that must be carefully timed...)
in spite of the above, please also note: "How does absorption occur in the small intestine? The presence of calcium is an influencing factor. Magnesium and calcium have a natural affinity for each other. Scientists have learned that if either of the minerals is consumed greatly in excess, it will be carried out of the system with the aid of the other element. However, these minerals are absorbed more easily when they are both present than when either is present alone. Thus, a deficiency of either element can cause a deficiency of the other as well, particularly in tissues where they are needed."
ps exercise and stress also increase the body's magnesium demand.
finally, if you get tested ensure your serum level is at LEAST 0.90 mmol/L ('normal' range is 0.70 - 1.10 mmol/L, so ensure that you stay in the top half of the range).
if you incorporate all that, including a successful boost to your serum levels, and still aren't sleeping, 1) i'll be amazed, and 2) then we'll try harder to find the solution
remember let me know where you are so i can try to find you a local source for mag glycinate. ttfn!