Predator Nutrition 3D Energy Drink

£2.99 (per can), predatornutrition.com

If you’re really flagging and need to perk yourself up for a monster workout, one can of Predator Nutrition’s 3D Energy Drink contains a whopping 200mg caffeine. That’s going to be far too much for some, so only drink if you’ve got a good caffeine tolerance. Also included is added taurine, to assist blood flow; L-carnitine, to help with fat oxidation; energising B vitamins; and panax ginseng, a root shown to improve cognitive function.