Collection: Gu-Maurten-Tailwind Race Kits

A good rule of thumb is to aim for 30 g of carbohydrates every 30 minutes. Since most energy gels contain 22 to 25 g of carbohydrates, a simple strategy is to take one gel 10 to 15 minutes before the race, another at 30 minutes, and then one every 30 minutes after that. You can top up your carbohydrate intake with sports drink available on course. Individual needs vary, but this is a solid starting point for most runners.

Science in Sport (SiS) produces both isotonic and non-isotonic energy gels. The SiS GO Isotonic gels are designed to be isotonic, meaning their carbohydrate concentration matches body fluids for fast absorption without the need for extra water. This can make them easier on the stomach for some athletes.

Other SiS products, such as SiS Beta Fuel gels, are high-carbohydrate formulations and are not isotonic. These are designed for higher fueling demands and may be taken with water.

Compared to traditional hypertonic gels that require fluid to aid digestion, isotonic gels like SiS GO Isotonic may reduce the risk of gastrointestinal discomfort for some users.

The name of the game is staying on top of your carbohydrate needs. Aim to start fuelling 30 minutes in, then take one every 30–45 minutes after that, depending on intensity and personal tolerance.

Beginner athletes might prefer to start fuelling around the 45-minute mark at first, then work up to fuelling earlier and more regularly.

Everyone's gut is a little different, so we always recommend practicing your fuelling strategy in training before race day. Never try something new on race morning!

Some of our gels are caffeinated and some are caffeine-free, so you can choose what fits your training plan (check each product page for details). They're formulated to be easy on digestion, but as with any new fuel source, we recommend testing them during training first to see how your body responds.