I'm adding magnesium to my diet and have read about how there are a lot of different types. Well, it's recommended to get around 400mg/day however I assume this means the amount the body needs, not what's in the pill.
The effectiveness of a magnesium supplement is determined by its...
 amount of elemental magnesium in the compound (i.e., the general weight of magnesium to total chelate weight); AND
 bioavailability (i.e., amount that is absorbed in the intestines and ultimately available for biological activity in your cells and tissues)
So I'm trying to compile a list...
Magnesium Sulfate ---> Elemental Mag = 10%, Bioavailability = ?
Magnesium Chloride ---> Elemental Mag = 12%, Bioavailability = ?
Magnesium Oxide ---> Elemental Mag = 60%, Bioavailability = 4%
Magnesium Carbonate ---> Elemental Mag = 45%, Bioavailability = 30%
Magnesium Hydroxide ---> Elemental Mag = 42%, Bioavailability = ?
Magnesium Citrate ---> Elemental Mag = 16%, Bioavailability = 90%
Magnesium Lactate ---> Elemental Mag = 12%, Bioavailability = 99%
Magnesium Glycinate ---> Elemental Mag = 18%, Bioavailability = 80%
Magnesium Malate ---> Elemental Mag = 6.5%, Bioavailability = ?
Magnesium Taurate ---> Elemental Mag = 9%, Bioavailability = ?
Alot of those elemental numbers came from this government website so it's probably pretty accurate. But "bioavailability" is apparantly a new concept in the world of magnesium and actual numbers are harder to track down. Lots of websites said that Citrate had the highest levels, but I actually read that Lactate did, with Citrate following behind it. Then, because Malate and Taurate are also Chelates, they have high %'s too.
What threw me for a loop was on Relentless Improvement's website, for Ortho Bone, AOR's data sheet says the following: "But compared to other sources of the mineral, magnesium oxide has extremely low bioavailability (22.8%) .... Magnesium citrate is certainly somewhat better, at 29.64% absorption, but itís still far from the best magnesium you can choose. Much better absorption is available from other forms Ė especially fully-reacted magnesium aspartate, with a remarkable 41.7% bioavailability."
That really threw me for a loop. Every single site that has listed the bioavailability for oxide has said it is either 4% or below... I have no clue where this 22.8% is that AOR is listing is coming from. If it were that high, it would make Mag-Oxide pretty worthwhile, but we all know it's a worthless supplement even with an elemental of 60%... Also, that 29% for citrate is screwey too... Citrate has the highest or second highest bioavailability... If it were just one weird number from AOR, okay fine. But two really odd numbers makes me believe that AOR's facts are wrong. Anyway, I'm not here to call AOR into question because I love them, I'm just trying to get legit numbers for the rest of the abovelisted magnesium compounds (or correct any mistakes I have) so I can order the proper supplement.
Btw, what is "Magnesium Amino Acid Chelate"? Is that another name for Mag Citrate? I can't quite figure it out.
EDIT: So just for those non-math inclined people out there, this is how you calculate how much mag a pill has:
(mg powder in pill) x (elemental %)/(100) x (bioavailability %)/100 = actual mag you are getting
Example: 500mg Mag Oxide
(500mg) x (60%)/100 x (4%)/100 = 12g of magnesium
Kind of a big difference eh? In my opinion, someone should sue the manufacturers for false advertising. Who the hell (Excuse my language) knows this crap?
Edited by ozone, 22 July 2007 - 03:00 AM.