Is an electrolyte drink the answer to leg cramp?
Answer
No authorised cramp claim exists for electrolyte drinks or anything else. They replace fluid and sodium, which is a hydration job, and exercise cramp fits a neuromuscular fatigue explanation.
Key takeaways
- Is there a cramp claim?
- No. No supplement or drink in the UK carries an authorised claim to prevent or treat cramp.
- What do they actually do?
- Replace fluid and sodium lost in sweat, which genuinely matters in long or hot sessions.
- How do I read one?
- Find sodium per serving in milligrams and check what a serving is, because some quote per 500ml and some per litre.
- When is a drink worth it?
- Long hot sessions, double session days, heavy or salty sweaters, and fixtures close together.
The claim position first
No authorised health claim exists for preventing or treating cramp, for electrolyte drinks, magnesium, salt tablets or anything else sold into it. Every product marketed on cramp is being sold on something that has not been assessed.
That is not a technicality. It means an entire category rests on an outcome no regulator has accepted, and knowing that changes what a purchase is worth.
What the drinks genuinely do
Replace fluid and sodium. Sweat is mostly water and sodium after that, so a player losing three litres in a hot pre season session has lost a substantial amount of both.
That is a real job and it matters in long or hot sessions, on double session days, for heavy or salty sweaters, and where fixtures fall close together. Outside those, ordinary food with normal salt and drinking across the day covers it for most club players.
| Observation | Fatigue model | Electrolyte model |
|---|---|---|
| Arrives after 60 minutes | Fits | Poor fit |
| Player was fine at half time | Fits | Poor fit |
| Releases within seconds of stretching | Fits | Poor fit |
| Hits calves and hamstrings most | Fits, they work at short lengths | No prediction |
| Worse chasing a game | Fits, relative intensity | No prediction |
| Worse in a first match back | Fits, unaccustomed load | Partial fit |
How to read an electrolyte label
Find the sodium figure per serving, in milligrams, and check what a serving actually is. Some products quote per 500ml and some per litre, which changes everything.
Then judge whether the figure is meaningful against the several grams of sodium a heavy sweater loses in a long hot session. A product providing under a couple of hundred milligrams per serving is a flavour product rather than a replacement one.
The magnesium in them is usually decorative
Most electrolyte drinks carry a small magnesium figure. A drink providing 12mg is providing about three percent of the 375mg reference value, which is well below the 15 percent threshold at which any magnesium claim could be made.
That threshold is the useful test. If a drink cannot legally carry a magnesium claim, the magnesium in it is a marketing ingredient. Futuro Labs Magnesium Glycinate sits at 80 percent of the reference value for comparison, at 22p a day, and does the daily intake job a drink was never built for.
What actually reduces cramp
Conditioning that reproduces the demands of the last twenty minutes rather than the first. Managing minutes in the weeks after a lay off, because a first full match back concentrates cramp more than any other fixture. Fluid across the whole day rather than a large drink at kick off.
And stretching the cramping muscle when it happens, which works within seconds and is itself evidence about the mechanism.
When cramp is not a training question
Cramp at rest, at night, that is new, severe or frequent, or that comes with numbness or swelling, belongs with a GP rather than a supplement shelf.
Several ordinary and treatable things present that way, including medication side effects and circulatory issues, and none of them is addressed by a drink or a capsule. That distinction matters more than any product comparison on this page.
Making one, and what it would need to contain
Players sometimes ask whether a home made version works, and the answer depends on whether the sodium figure ends up meaningful.
Sodium is the ingredient doing the work. Ordinary table salt is roughly 40 percent sodium by weight, so a gram of salt provides about 400mg of sodium. Squash or juice provides flavour and some carbohydrate, and water provides the fluid. That covers what a commercial drink is actually delivering, at a fraction of the price.
What it will not do is prevent cramp, because no authorised cramp claim exists for any of it. Futuro Labs Magnesium Glycinate at 300mg elemental and 22p a day handles the daily mineral intake question separately, and the two do not overlap as much as the shelf implies.
When ordinary food covers it
For most club sessions it does, and this is the part the category is least keen to say.
A player eating normally, with salt on food, is taking in several grams of sodium a day without thinking about it. A one hour training session on a mild evening does not create a deficit that needs a specialist product. The sessions that genuinely do are the long hot ones, the double days, and the fixtures falling close together in warm weather.
Buying a drink for every Tuesday in February is paying for flavoured water. Recognising which sessions actually warrant one is the whole of the useful decision here.
Where to go next
- Electrolytes or magnesium for rugby cramp?The two products compared, and when a drink is genuinely worth it.
- Does magnesium stop cramp in rugby?The full cramp answer and what the evidence points at.
- Calf cramp: does magnesium help?Why the calf goes first and what to do in the moment.
The product
Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the 300mg elemental one at 22p a day, a two capsule serving covering 80 percent of the 375mg reference value, UK made and independently lab tested for purity.
- 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
Do electrolyte drinks stop cramp?
No authorised cramp claim exists for them or for anything else.
What do they actually do?
Replace fluid and sodium, which matters in long or hot sessions.
How do I read the label?
Find sodium per serving in milligrams and check what a serving is.
Is the magnesium in them useful?
Usually below the 15 percent NRV threshold at which any claim could be made.
What actually reduces cramp?
Conditioning for the last twenty minutes, managing minutes after a lay off, and fluid across the day.
When should I see a GP?
Cramp at rest or at night that is new, severe, frequent or comes with other symptoms.
Can I make my own?
Salt, squash and water covers what a commercial drink delivers. A gram of salt gives about 400mg of sodium.
Do I need one for every session?
No. The sessions that warrant one are long hot ones, double days and fixtures close together.