Testing of magnesium products purchased on Amazon show that consumers need to beware of low quality products.
Magnesium is critical to human health as a cofactor in more than 300 enzyme systems that regulate everything from protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Yet 60 percent of Americans don’t get enough of this critical mineral, which may be why magnesium supplement sales have been growing. Recent testing of magnesium supplements sold on Amazon demonstrate that consumers need to be smart shoppers to avoid low quality products with deceptive labels.
NOW Foods conducted quality testing of 16 magnesium glycinate brands purchased on Amazon. The results are not encouraging. Almost all brands that were tested failed to include the chelated magnesium form claimed on the label—magnesium glycinate. This is critical. As we’ve discussed elsewhere, there are a number of different forms of magnesium in supplements. Some of these forms (magnesium oxide and sulfate) are generally found in cheaper, lower quality supplements and can have a laxative effect. The forms recommended by most integrative doctors (magnesium glycinate, taurate, malate, or chloride) are better absorbed by the body and are not associated with laxative effects.
NOW’s testing indicates that many brands either knowingly or unknowingly blend glycine with magnesium oxide or carbonate and then label the product as “Magnesium Glycinate.” This allows unscrupulous brands to sell their mislabeled products at a lower cost but fools consumers into thinking they are buying the chelated, more bioavailable form.
NOW’s testing also found some products were mislabeled intentionally in order to indicate higher potency.
See NOW’s full press release, which includes the brands tested and the results.
We’ve reported previously on some of the impressive benefits of magnesium, notably for heart health and sleep. There are of course many other benefits to magnesium. Recall, too, that even though magnesium’s benefits for heart health are well-documented in the scientific literature, the FDA insisted that health claims on magnesium supplements say that the evidence is “inconsistent and inconclusive”—part of the agency’s long-time goal of censoring speech about the benefits of natural products, lest consumers choose these safe, natural, and affordable options to manage heart health over expensive and (often) ineffective prescription drugs.
