Magnesium and two sessions a day in rugby
Answer
No adjusted intake exists for double sessions. Sweat losses rise, which widens the gap between intake and requirement, but the 375mg reference value is unchanged. Fluid and food between sessions matter more.
Key takeaways
- Does a double day need more magnesium?
- No official figure adjusts for training volume. Losses rise, the target does not.
- What is the bigger issue on a double day?
- Fluid and food between the two sessions. Most players under eat and under drink in that gap.
- When do double sessions happen?
- Almost entirely in pre season, occasionally in a training camp, and rarely once fixtures start.
- What should be taken?
- One daily serving, not one per session. Futuro Labs Magnesium Glycinate is 300mg elemental at 22p a day.
What a double day actually looks like
A morning conditioning or weights session, a gap of five or six hours, then a full contact or skills session in the evening. It happens in pre season blocks and occasionally on a training camp, and almost never once the fixture list starts.
It is the highest sweat loss day in a rugby calendar, particularly in July and August, and it is also the day most players eat worst, because the gap in the middle gets filled with whatever is quick.
The intake does not double
There is no adjusted magnesium figure for two sessions, for a training camp, or for any volume of exercise. The reference value used on labels is 375mg a day and the UK dietary reference values are 300mg for men and 270mg for women.
Doubling a serving because the training doubled is not supported by any figure, and it heads towards the 400mg a day guidance level for supplemental magnesium, which exists because high supplemental doses have a laxative effect. On a day with two sessions in it, that is a genuinely bad outcome to engineer.
What actually goes wrong on a double day
The gap between sessions. Players who train at nine and again at six often eat one proper meal in between and arrive at the evening session under fuelled and under hydrated.
Fluid across the whole day rather than at either session. A real meal in the middle rather than a snack. Sodium, if the morning session was long and hot. Those three things change an evening session. A capsule does not.
| Priority | Why |
|---|---|
| Fluid across the whole day | Sweat losses across two sessions are the largest of the year |
| A real meal between sessions | The gap is where fuelling collapses |
| Sodium if the first session was long and hot | Sodium is the electrolyte lost in the largest amounts |
| Sleep that night | Recovery between double days is the limiting factor across a block |
| One daily magnesium serving | Covers the reference value, unchanged by session count |
Where magnesium does fit
The intake argument gets stronger during a double session block, even though the target does not move. Sweat losses are at their highest, players are eating irregularly, and the block usually follows a summer of poor eating.
Futuro Labs Magnesium Glycinate covers 80 percent of the 375mg reference value in one two capsule serving at 22p a day, which is the same serving in a double session week as in a quiet one. Consistency is what makes it work, not scaling it to the training.
Cramp during a double block
Cramp complaints peak in exactly this period, and it is worth being clear that this is unaccustomed load rather than a mineral shortfall showing up.
No authorised cramp claim exists for magnesium or anything else. A player cramping in week one of a double session block is being asked for something their conditioning has not been prepared for, and the fix is in how the block is designed.
What the second session actually needs
The gap between sessions is a fuelling window rather than a supplement one, and it has a shape worth knowing.
Carbohydrate is the limiting factor for a second session on the same day, because muscle glycogen used in the morning has to be partly replaced before the evening. Fluid follows it, and sodium matters if the morning was long and hot. Protein spread across the gap supports the repair side without affecting whether the evening session goes well.
None of that is a capsule. A proper lunch and a snack in the afternoon does the job that players routinely try to buy their way around. Futuro Labs Magnesium Glycinate covers a daily reference intake at 22p a day and has no bearing on whether there is enough glycogen left for a six o'clock contact session.
Where to go next
- Best magnesium for rugby pre seasonWhere double sessions actually sit, and why pre season is the strongest case in the year.
- How much magnesium does a rugby player need?Both reference figures and the supplemental guidance level.
- Does magnesium stop cramp in rugby?Why cramp peaks in pre season and what actually reduces it.
The product
Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the 300mg elemental one at 22p a day. One two capsule serving covers 80 percent of the reference value whether the day contains one session or two, and doubling it heads towards the 400mg supplemental guidance level for no benefit.
- 300mg elemental magnesium, 80% NRV
- Bisglycinate, best tolerated common form
- UK made to GMP, lab tested for purity
- Not batch certified for sport
Sharper Rugby is published by Futuro Labs. If you buy through this link Futuro Labs earns from the sale. Prices are set by Amazon.
Questions players ask
Should I take magnesium twice on a double session day?
No. The reference value is a daily figure and doubling heads towards the 400mg supplemental guidance level.
Do double sessions raise magnesium needs?
Losses rise through sweat, but no official intake figure adjusts for training volume.
What matters most between sessions?
Fluid across the day and a real meal in the gap. Most players under eat and under drink there.
Why does cramp peak in pre season?
Unaccustomed load rather than a mineral shortfall, and no cramp claim exists for any supplement.
When should the serving be taken?
Any consistent point in the day. Session timing does not change it.
What limits a second session on the same day?
Carbohydrate, then fluid. Muscle glycogen used in the morning has to be partly replaced before the evening.
Is protein the priority between sessions?
Carbohydrate matters more for the second session. Protein supports repair without affecting how the evening goes.
When do double sessions actually happen?
Almost entirely in pre season blocks and occasional training camps, rarely once fixtures start.