Q. I have read that magnesium glycinate is the best form of magnesium because it is better absorbed and does not cause constipation. What do you think?
Dr. Murray: Let me be very clear here is NOT a single human study ever conducted with magnesium glycinate and absorption studies in animals show that magnesium glycinate is NOT better absorbed compared to popular forms of magnesium. Most statements on magnesium glycinate are completely without merit – that is a polite way of saying they are false and ignorant. It is hard to understand the rationale where these statements come from. It’s baffling to me. I think some people and companies are simply taking the data from iron glycinate and trying to extrapolate it to magnesium glycinate. There is no question that iron glycinate is a nice form of iron, but the absorption of iron and magnesium are significantly different so we cannot extrapolate the data on iron glycinate. With magnesium the key is easy ionization of the magnesium versus facilitated (carried) absorption as with iron. While iron supplements are constipating for some, magnesium salts like magnesium hydroxide and chloride can cause a loose stool. Magnesium bound to Krebs cycle intermediates like citrate and malate as well as aspartate have significant support in the medical literature including many clinical studies.
