Running Gels & Nutrition
Fuel your long runs and races. What to take, when to take it, and which products to trust.
When should I take gels?
For runs under 60 minutes, you don't need gels - your glycogen stores are sufficient. For runs of 60–90 minutes, one gel around the 45-minute mark helps. For anything longer, take one every 30–45 minutes from 30 minutes in. Practise your race nutrition in training - race day is not the time to experiment.
SiS Go Energy Gels
From 45 minutes into a run, every 30–45 minutes
The UK's best-selling running gel. Isotonic formula means no water required. 22g of carbohydrates per gel with a wide range of flavours.
Maurten Gel 100
25g carbs per gel - ideal for marathon and beyond
Hydrogel technology for less GI distress. Used by Eliud Kipchoge and many elite marathoners. Tastes of almost nothing - a neutral experience.
High5 Energy Gels
Ideal for long training runs to practise race nutrition
23g of carbs per gel, affordable multi-packs, and well-tolerated by most runners. A solid choice for training long runs when you don't want to use race-day gels.
Precision Hydration Electrolyte Tablets
Pre-run hydration and during runs over 90 minutes in heat
Dissolve in water to create a light electrolyte drink. Prevents hyponatraemia on hot days and long races. No sugar - ideal for easy and recovery runs.
Plan your race nutrition
Use the RunReps Running Calories Calculator to estimate energy expenditure and plan how many gels you'll need.
Running Calories Calculator →Running nutrition questions answered
When should I start taking gels during a race?
Start earlier than you think - around 30 to 45 minutes into a race, even if you don't feel like you need one yet. Your body absorbs carbohydrates gradually, and by the time you feel fatigued, you're already behind. For a marathon, that means 6–7 gels across the race if you're running 3–4 hours.
Do I need to take gels with water?
It depends on the gel. Isotonic gels (like SiS Go) are designed to be taken without water - they're already diluted to match the concentration of body fluids. Standard gels (like Maurten) should be followed by a small amount of water to aid absorption. Check the label and practise in training.
What causes GI problems with gels during races?
The most common causes are taking gels too concentrated (without water when required), taking them too frequently, switching brands on race day without training on them, and running at a pace that diverts blood away from digestion. Practise your exact race nutrition plan - same brand, same timing - in your long training runs.
Do I need electrolyte drinks as well as gels?
For runs under 90 minutes in normal conditions, water is usually sufficient. Over 90 minutes - especially in heat - electrolyte tablets or drinks prevent sodium depletion, which causes cramping and, in severe cases, hyponatraemia. Many runners combine gels (for carbs) with electrolytes (for sodium and minerals) rather than using sports drinks.
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