There are various causes of high blood pressure (hypertension), though the most common cause is calcium in the muscles that form the blood vessels.

Magnesium is a simple way to keep the calcium out of these muscles, thereby lowering blood pressure.  All forms of magnesium are not the same though.  I prefer either magnesium malate (my first choice) or magnesium citrate.  Both the malic acid (malate) and citric acid (citrate) are precursors for the formation of adenosine triphosphate (ATP), which fuels cells and allows them to function properly.

Magnesium oxide should be avoided at all costs.  When magnesium oxide is mixed with water magnesium hydroxide is formed.  As with all hydroxides (OH), magnesium hydroxide is caustic and powerful free radical, and will burn healthy tissue.  This is why magnesium hydroxide is commonly used as a laxative.  As the magnesium hydroxide burns the intestinal wall fluid is secreted in to the intestine and peristalsis stimulated leading to the laxative effect.  Burning the intestinal wall though with any hydroxide can lead to an increased risk of colitis and intestinal cancer.

Magnesium works better if taken in the absence of calcium.  Magnesium works in a similar fashion as prescription calcium channel blockers (CCBs).  Between the nerve ends is a gap called a synapse. When calcium enters this synapse the blood vessels constrict raising blood pressure.  So CCBs work by filling the synapse to prevent calcium from entering.  This relaxes the blood vessels lowering the blood pressure.  Magnesium and calcium are antagonistic to each other.  So higher doses of magnesium to calcium will allow the magnesium to displace the calcium out of the synapse, which again relaxes the blood vessels lowering the blood pressure.  We used this principle in the hospital to lower the blood pressure of women with preeclampsia associated hypertension.  IV magnesium is given to immediately drop the blood pressure.

Keep in mind that high doses of magnesium are laxative, so I generally recommend no more than 300mg of magnesium 2 times a day on an empty stomach.  Taking it on an empty stomach ensures that little or no calcium will be present since the more calcium present the less effective the magnesium will be.

Also remember that as the blood pressure goes down your medication may need adjusting.  So let your doctor know what you are doing.  And never go off your meds cold turkey!

If the magnesium is not effective, or strong enough by itself, there are a few other options to look in to.  For instance the herbs coleus forskohlii, kudzu, and cactus grandiflorus (night blooming cereus) are all excellent choices for lowering blood pressure.  Cactus is a weak cardiac glycoside, so it should not be used if you are taking another cardiac glycoside like Digoxin.

Remember to drink plenty of spring water throughout the day to help flush excess salts out of the body and to keep the kidneys healthy.