OXIDE: Non-chelated forms include magnesium oxide and magnesium sulfate and are considered less absorbable than are chelated varieties. Magnesium oxide contains the highest amount of elemental magnesium per tablet of any magnesium supplement at 60 percent, according to the National Institutes of Health but magnesium oxide is not absorbed well in the intestines, at only a 4 percent rate. A 500 mg tablet of magnesium oxide contains 300 mg of elemental magnesium, although only 12 mg or so is absorbed. The remaining magnesium stays in the intestines for a while, creating a strong laxative affect.<br /><br />CITRATE: Magnesium can be chelated, which means attached to an organic acid, such as citrate and considered more absorbable than non-chelated varieties. Magnesium citrate is more easily absorbed and for that reason priced higher than magnesium oxide.<br /><br />Magnesium is associated with prostate cancer, diabetics and muscle cramps. It is unlikely to get too much magnesium from food alone, but can get too much magnesium from supplements. I have an extremely healthy diet but still after few blood tests it seems that I need to increase my magnesium to avoid muscle cramp when surfing and doing other sports. I do not take any other pills or medicine for any condition at all. So;<br />1. I take magnesium citrate not oxide<br />2. Fat blocks magnesium but it works fine for me since I am on a low fat, no salt diet so Instead of 400, I take only one 200 mg a day with a healthy diet of sardines, sprats, salmon, avocado, almonds, nuts, sesame-flax seed, beans etc. high in magnesium and all other minerals<br />3. I only take it one hour after a full meal and never with an empty stomach. Magnesium acts as laxative and calcium increases constipation<br />4. I only purchase 100% magnesium citrate in powder form so I avoid all additives required to produce any form of pill and identified as vegetarian additives in the pills<br />5. Now Foods and Swanson are priced the same for the same amount of magnesium citrate and both work well.

Been taking this for about six weeks. Energy is more consistent and I feel less sluggish in the afternoons. Happy with the purchase.

Third-party tested, clean label. That's what I look for first. Actually works too, which is a bonus.

Took this for a month and didn't notice much change. Might just not work for me personally.

Capsules are on the larger side, hard for me to swallow. Product might work but it's not practical.

Switched from a more expensive brand and honestly can't tell the difference in results. Saves money.