All exercises and fitness run on a molecule called ATP, and a muscle only holds a few seconds' worth. Creatine is the reserve your body uses to rebuild it. Top up the reserve and the muscle is ready to go again sooner.

Creatine doesn't soak into a muscle. It goes in through a doorway in the cell wall, and that doorway only opens when sodium goes through with it. The 350mg of sodium in every scoop is the key opening the door to creatine.

The enzyme that rebuilds ATP from creatine only works with magnesium alongside it. Creatine stores the energy; magnesium lets your muscle spend it. Magnesium helps your body turn food into energy and helps your muscles work normally.

Creatine draws water into the muscle, which is part of how it works. Sweat takes sodium, potassium, calcium and magnesium out; one scoop puts them back, so the water stays useful. One scoop a day, and you're fully topped up in three to four weeks.

Your nerves fire all day: at work, in the gym, at a screen. Each signal needs something to help it stand down again, and magnesium is one of those things. Not enough of it and the body finds it harder to rest at night.

Around one in five UK adults don't get enough magnesium from food. Rest gives you 280mg a glass, 75% of your daily need, so the gap is covered and builds your much-needed magnesium stores

Magnesium on its own is harsh on the gut, which is why cheap forms have a laxative reputation. Rest uses magnesium glycinate, magnesium bound to an amino acid called glycine, which is gentle at a proper dose. Bulky in capsules, but easy in a glass.

Muscles use calcium to contract and magnesium to release, so the session's work finishes at night. Zinc builds the proteins your body repairs with while you sleep. Magnesium helps reduce tiredness and fatigue, so seven o'clock feels like seven o'clock.

Concentration is your brain passing signals between cells, and those signals are carried by chemical messengers. Vitamin B5 is one of the things your body uses to make them. 

Caffeine doesn't make energy. It blocks the signal that tells you you're tired, then hands the tiredness back at 3pm with interest. 

Vitamin B5 makes the messengers. KSM-66 ashwagandha handles the stress. Lion's mane goes at the brain fog. Citicoline is the material your brain builds its own cell walls from

Your gut makes enzymes, proteins whose job is to break food into pieces small enough to absorb. Each enzyme handles one kind of food. Digest adds five: amylase for starch, protease for protein, lipase for fat, lactase for dairy sugar, cellulase for plant fibre.

Food that isn't fully broken down sits in the gut and ferments, and the gas is what you feel as bloating. Fennel seed is what half the world chews after dinner to ease exactly that: bloating and trapped wind. Digest concentrates it 10:1.

Two live cultures, Lactobacillus acidophilus LA85 and Bifidobacterium bifidum BBi32, 1.5 billion of each, named to the exact strain. And 300mg of inulin, a plant fibre from chicory root, the kind of fibre gut bacteria feed on.

Enzymes only work when they meet food, which is why Digest is taken with your main meal, not after. Live cultures and fibre work on the daily routine, not the occasional rescue. You finish the meal and get on with your evening.