Best magnesium for rugby players

By Tom Francis·Updated 2026-09-03·3 sources·Editorial policy

The criteria, in order

Elemental content per serving comes first, because it is the only figure that describes how much magnesium a player actually takes. Everything else is secondary to it.

Then the form, because it decides tolerability across a season. Then whether the label declares both the compound weight and the elemental figure, which is a fair proxy for how honest the rest of the label is. Then testing and manufacturing. Then cost per day, calculated from servings rather than capsules.

Why elemental content decides it

Magnesium is always bound to something. The weight on the front of the pack is usually the whole bound compound, and the proportion that is actually magnesium varies enormously by form.

Magnesium bisglycinate is roughly 20 percent magnesium by weight, so 1500mg of bisglycinate yields 300mg elemental. Magnesium oxide is around 60 percent by weight but absorbs poorly, so a high elemental figure there does not translate. Two products showing the same big number on the front can differ several fold in what reaches the player.

Form, for a player taking it all season

Oxide is the cheapest and the least well absorbed, and it is the form most associated with loose stools at a full dose. Citrate absorbs better and appears in most powders. Bisglycinate is chelated to an amino acid and is generally the most comfortable of the three at a full daily serving.

For a rugby player taking a serving daily from July to April, tolerability matters more than a few pence of unit cost, because the product that upsets a stomach gets abandoned in week three.

What a good label looks like

Futuro Labs Magnesium Glycinate states 750mg of magnesium bisglycinate per capsule, a two capsule serving of 1500mg, and 300mg of elemental magnesium at 80 percent NRV. All four figures are printed, which is what allows a buyer to compare it to anything else.

It is vegan, UK made and independently lab tested for purity, and it is not batch certified for sport. That last point is stated on every page here rather than glossed, because a player who could be tested needs a certified product regardless of everything above.

Cost per day, done properly

Amazon shows a price per count, which is per capsule, and that flatters any product with a multi capsule serving. The comparison that works is pack price divided by servings.

Futuro Labs Magnesium Glycinate is 19.99 pounds for 180 capsules, which is 90 two capsule servings, so 22p a day. The 90 capsule pouch is 9.99 pounds for 45 servings, which is also 22p. A product at half the tub price with a three capsule serving and no elemental figure is not cheaper, it is simply harder to check.

The three questions that settle most purchases

Nearly every magnesium decision comes down to three checks, and a player who runs them in a shop aisle will be right more often than one reading reviews.

First, is an elemental figure printed at all? A label without one has removed the only number that allows comparison, and that is a choice the manufacturer made. Second, how many capsules make the serving the elemental figure refers to? A 300mg elemental serving from four capsules is a different product from the same figure at two. Third, what is the pack price divided by servings? Not by capsules, which is what Amazon shows.

Run those on Futuro Labs Magnesium Glycinate and the answers are 300mg printed, two capsules, and 22p. Run them on most of the shelf and at least one of the three comes back missing.

Where to go next

• Futuro Labs Magnesium Glycinate: the full labelBoth pack sizes, elemental content, NRV and cost per day.
• Magnesium for rugby playersSweat loss, cramp, evening training and what the claims cover.
• How to read a supplement labelThe general method behind all of these criteria.

Questions players ask

Sources

• EFSA register of nutrition and health claims
• National Diet and Nutrition Survey, gov.uk
• Committee on Toxicity, magnesium