When it comes to taking a mineral supplement, there are several things to consider when trying to maximize your supplementation. The primary goal is to absorb the most amount of the mineral from the fewest number of capsules and without any side effects. So, how can this best be accomplished?


Form Does Matter

One factor must always be confronted – by their very nature minerals are not particularly well absorbed by the human body. In addition, various dietary, lifestyle, and health factors can have a negative impact on mineral absorption. For example, oxalic acid (found in high amounts in spinach, rhubarb, and black tea), phytic acid (found in whole grains, nuts, seeds, beans, and potatoes), caffeine, antacids, acid-blocking medications, and malabsorption syndromes, can all decrease mineral absorption in the body.

One of the barriers to absorption that can be overcome is optimizing the form the mineral comes in. This is simple chemistry – certain forms of minerals are better absorbed than others.

For example, magnesium in the forms of magnesium bisglycinate and dimagnesium malate is better absorbed than the magnesium in magnesium oxide. And absorption of the magnesium in magnesium bisglycinate edges out the absorption of the magnesium in dimagnesium malate.



Magnesium Absorption Graph

A fair question to ask is: what makes magnesium bisglycinate the best absorbed form of magnesium?

The answer is really just three words: amino acid chelate. To create an amino acid chelate, a poorly absorbed inorganic mineral (like magnesium) is molecularly bonded and encircled by one or more amino acids, which creates a much more readily absorbable organic compound. The process of mineral chelation has been pioneered by Albion Laboratories of Layton, Utah.

A mineral’s absorption also depends on how “soluble” the mineral is. Solubility depends on how acidic the absorption environment is. The more acidic the environment, the more soluble and the better absorbed the mineral will be.

Magnesium bisglycinate is an amino acid chelate that consists of one molecule of magnesium bound to two molecules of the amino acid glycine. Because glycine helps to increase the acidity of the small intestine – voila – better absorption.

But improved absorption from utilizing amino acid chelates is not limited to magnesium. For example, more iron will also be absorbed from iron that is attached to bisglycinate than from the same amount of iron that is bound to sulfate (ferrous sulfate). In a study of healthy men, four times as much iron was absorbed from iron bisglycinate than from iron sulfate (ferrous sulfate).1

In a study of pregnant women, 25 mg of iron from iron bisglycinate was just as effective as 50 mg of iron from iron sulfate in preventing iron deficiency anemia.2

In the case of zinc, a glycinate chelate also appears to offer superior absorption. In a study of healthy female volunteers, 43 percent more zinc was absorbed after taking oral doses of zinc bisglycinate compared to zinc absorbed from the same amount of zinc gluconate.3

Bisglycinates also provide another important benefit. As noted above, the phytates that are found in many whole foods will bind to minerals and inhibit their absorption. However, the two glycine molecules in a bisglycinate chelate (“bis” means two) will block the attachment of phytates to the mineral.


Balancing Absorption With Concentration

In addition to its ability to be absorbed, the concentration of a mineral in a supplement formula is also important. This is especially true when the mineral is in an encapsulated product. The concentration – or how much of the ingredient is mineral compared to the substance the mineral is bound to in the ingredient – will determine how much of the mineral can be squeezed into the capsule.

Unless you don’t mind taking a lot of capsules or taking a so-called horse pill, finding a supplement with an optimum balance between absorption and concentration is hugely important. This is particularly true when considering the “macro” minerals that take up large amounts of space in the capsule. “Macro” minerals are the ones required by the body in higher amounts, such as calcium and magnesium.

Dicalcium malate and dimagnesium malate are two very good examples of calcium and magnesium that are both well-absorbed and that also have higher mineral concentrations.

The “di-” prefix means there are two molecules of the mineral – calcium or magnesium – for each malate molecule (an organic acid), thus allowing for more mineral per molecule.

Dicalcium malate is 29 percent elemental calcium compared to calcium citrate, which is only 19 percent elemental calcium. Remember – greater concentration means more calcium per capsule.

Dimagnesium malate is also more concentrated than magnesium bisglycinate (20 percent magnesium versus 8 percent magnesium, respectively). But because magnesium bisglycinate is a bit better absorbed than dimagnesium malate, the magnesium bisglycinate is ideal for a powdered product, whereas, the higher concentration of magnesium in dimagnesium malate makes it a superior choice for an encapsulated product.


What About Tolerability?

As a general rule, the better a mineral supplement is absorbed, the better the supplement is tolerated. Also, the molecular structure of the mineral can have other beneficial effects. For example, in the case of magnesium bisglycinate, the two molecules of glycine take up active attachment sites on the molecule, which prevents water from attaching, thus reducing the product’s potential laxative effect.

Iron – which is notorious for producing yucky gastrointestinal side effects – is better tolerated in the form of iron bisglycinate than when it’s in the form of iron sulfate. In a double-blind clinical study, iron in the bisglycinate form produced less gas, less bloating, and less nausea than iron in the sulfate form.4

BioMins (with copper and iron) and BioMins II (without copper and iron) feature dicalcium malate, dimagnesium malate, and various trace mineral glycinate chelates.


1. Bovell-Benjamin AC, Viteri FE, Allen LH. Iron absorption from ferrous bisglycinate and ferric trisglycinate in whole maize is regulated by iron status. Am J Clin Nutr 2000;71:1563-1569.

2. Milman N, Jonsson L, Dyre P, et al. Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial. J Perinat Med 2014;42(2):197-206.

3. Gandia P, Bour D, Maurette JM, et al. A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers. Int J Vitam Nutr Res 2007;77(4):243-248.

4. Coplin M, Schuette S, Leichtmann G, Lashner B. Tolerability of iron: a comparison of bis-glycino iron II and ferrous sulfate. Clin Ther 1991;13(5):606-612.