Why our electrolytes come from the sea

The electrolyte sachets by the till are mostly sugar, a flavouring, a colour and a pinch of the cheapest form of each mineral. Magnesium oxide, usually, which is about the worst form you can buy and the one most likely to send you to the loo rather than into your muscles.

We wanted the minerals in the Summit Stack to come from somewhere. The magnesium comes from seawater. It is drawn off the Irish coast, concentrated and dried, and it arrives with the seventy-odd trace minerals seawater holds rather than as one isolated compound. The ingredient is Aquamin Mg, a cousin of the seaweed calcium in the daily blend. The salt is the same Utah seabed salt you already know (Celtic sea salt in the UK pouch).

Magnesium contributes to electrolyte balance, to normal muscle function and to a reduction of tiredness and fatigue. It is involved in several hundred of the reactions that run a body, from making energy to switching a muscle off after it has fired, and most of us do not get the 300 or so milligrams a day we are meant to. We believe it is the mineral hard training strips out fastest and the one most sachets barely bother with, and that a lot of what people call poor recovery, night cramps and a wired-but-tired evening is simply low magnesium.

Two forms of mineral, both from the sea, both with a place you could point to on a map.