How much magnesium does a rugby player need?

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

The two numbers, and why both exist

Labels use a nutrient reference value, which for magnesium is 375mg a day. That figure exists so a product can state a percentage and so claims have a threshold to clear, which is 15 percent of it.

Separately, the UK sets dietary reference values as population intake targets, and for magnesium those are 300mg a day for adult men and 270mg for adult women. Both figures are correct and they answer different questions. A label saying 80 percent NRV is measuring against 375mg.

There is no athlete figure

No UK or EU body sets a separate magnesium intake for athletes, for team sport players, or for anyone by body mass. That absence is the honest answer to most versions of this question.

What training does is raise losses through sweat and raise turnover through energy metabolism. Both make hitting the existing target more difficult rather than making the target higher. Anyone quoting a rugby specific milligram figure has invented it.

What food actually provides

Magnesium is concentrated in seeds, nuts, wholegrains, pulses and leafy greens. Reaching the reference value from food is entirely possible and it takes deliberate choices, which is why average intakes across the UK population sit below it for a meaningful share of adults.

Where a supplement fits

The gap for most club players is not dramatic. A player already eating oats, wholemeal bread, nuts and some greens is closer to the target than they think, and a player living on white pasta and chicken is a long way from it.

Futuro Labs Magnesium Glycinate provides 300mg of elemental magnesium per two capsule serving, which is 80 percent of the 375mg labelling reference value and above both UK dietary reference values on its own. That is a substantial serving rather than a top up, which is worth knowing before adding it to a diet that is already reasonable.

The upper end

There is a separate figure for supplemental magnesium specifically. UK expert advice sets a guidance level of 400mg a day from supplements, based on the laxative effect of high supplemental doses rather than on any toxicity.

That applies to magnesium taken as a supplement, not to magnesium from food, which is not associated with the same effect. A 300mg elemental serving sits below that guidance level, and stacking several magnesium products together is where players run past it.

Adding up a real day

The abstract figures mean more against an actual day. Take a club player eating porridge with milk, a chicken and rice lunch, a handful of nuts in the afternoon and pasta with chicken in the evening.

Forty grams of oats is about 56mg. A large glass of milk adds about 28mg. Two hundred grams of cooked white rice contributes about 20mg and the chicken about 40mg. Thirty grams of almonds is about 80mg. Two hundred grams of cooked pasta is about 35mg with another 40mg from the chicken. That day lands somewhere near 300mg, which is at the UK dietary reference value for men and short of the 375mg used on labels.

Swap the white rice and pasta for wholegrain versions and add a portion of greens and the same day clears 375mg comfortably. That is the actual size of the gap, and it is why the honest description of a supplement here is insurance rather than necessity.

Where to go next

• Does a bigger rugby player need more magnesium?The body mass question, answered against the actual figures.
• Futuro Labs Magnesium Glycinate: the full labelElemental content, NRV and both pack sizes.
• How to read a supplement labelHow to check any of these figures on a product yourself.

Questions players ask

Sources

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