Magnesium side effects for rugby players
Answer
The common side effect is a laxative effect at higher supplemental doses, which is why UK guidance sets 400mg a day from supplements. Magnesium oxide is the form most associated with it.
Key takeaways
- What is the usual side effect?
- Loose stools at higher supplemental doses. It is the reason the 400mg supplemental guidance level exists.
- Which form causes it most?
- Magnesium oxide, which is poorly absorbed, leaves more in the gut and is the cheapest form on the shelf.
- What is the ceiling?
- UK guidance sets 400mg a day from supplements specifically. It does not apply to magnesium from food.
The realistic picture
For a healthy adult taking a normal serving, magnesium is well tolerated. The side effect that shows up in practice is a laxative one, and it is dose dependent and form dependent rather than universal.
Magnesium oxide is the main offender because it is poorly absorbed, which means more of it stays in the gut where the osmotic effect happens. Chelated forms such as bisglycinate are generally the most comfortable at a full serving, which is the practical reason Futuro Labs Magnesium Glycinate uses it.
The ceiling and where players run past it
UK guidance sets 400mg a day from supplements specifically. A 300mg elemental serving sits below it with 100mg of headroom.
Players exceed it by stacking rather than by overdosing one product: a dedicated magnesium supplement, a multivitamin and a ZMA product all contribute, and nobody adds up the panels. Anyone on prescribed medication, and anyone with kidney problems in particular, should raise a new supplement with a GP or pharmacist before starting it.
The full version
- How much magnesium does a rugby player need?The reference figures, food sources and the supplemental ceiling in full.
- What to look for in a magnesium supplementIncluding how to spot which form a product actually uses.
The product
Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the 300mg elemental one at 22p a day, using a chelated bisglycinate form rather than oxide, which is the practical difference across a full season of daily use.
- 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
Does magnesium upset your stomach?
At higher supplemental doses it can, particularly as oxide. Chelated forms are generally more comfortable.
How much is too much?
UK guidance sets 400mg a day from supplements. Food magnesium is not included in that figure.
Should anyone avoid it?
Anyone with kidney problems or on prescribed medication should speak to a GP or pharmacist first.
Do side effects depend on the dose?
Yes. The laxative effect is dose dependent, which is why the supplemental guidance level exists at 400mg a day.