Magnesium spray or capsules for sleep?

By Tom Francis·Updated 2026-09-03·2 sources·Editorial policy

The claim position, before the format question

Magnesium carries authorised claims for normal muscle function, normal protein synthesis, electrolyte balance, energy metabolism, and normal nervous system and psychological function, at 15 percent of the 375mg reference value or above.

None of those is a sleep claim, and no sleep claim for magnesium exists. That applies to a spray, a capsule, a flake bath and a night time branded product equally, so the format comparison cannot be settled on sleep.

What separates the formats

A capsule states a fixed dose per unit that can be checked against a threshold. A spray states what is in the bottle and cannot state what is absorbed through skin, so there is no dose to compare and no percentage NRV can be given.

Futuro Labs Magnesium Glycinate is 300mg of elemental magnesium per two capsule serving at 80 percent NRV, for 22p a day. That is a number a buyer can act on, which a spray by its nature cannot offer.

What actually affects sleep after training

Core temperature that has not yet fallen after a late session. Bright light through the evening. Caffeine taken before training, whose half life is roughly five hours. And a heavy meal eaten at half past ten.

All four are within a player's control and none costs anything, which is a less appealing answer than a product and a more useful one.

The full version

• Magnesium spray or capsules for rugby players?The format question in full, including what topical absorption claims rest on.
• Magnesium and sleep after evening rugby trainingWhat actually keeps club players awake on a training night.

Questions players ask

Sources

• EFSA register of nutrition and health claims
• Food supplements guidance, gov.uk