Energy gels have become a fixture in endurance sport — and for good reason. During sustained exercise lasting longer than 60–90 minutes, the body's stored glycogen begins to deplete, and maintaining pace or power output becomes progressively harder without exogenous carbohydrate. Energy gels solve this problem efficiently: they deliver fast-absorbing carbohydrates in a compact, portable format that can be consumed without slowing down. But not all gels are built the same, and choosing the right one for your sport, session length, and physiology makes a meaningful difference.
What Is an Energy Gel and How Does It Work?
An energy gel is a concentrated carbohydrate supplement in a viscous, semi-liquid form, packaged in a small single-serve sachet. The formulation is designed to be absorbed rapidly through the digestive tract with minimal gastric stress — a key requirement when the body is under exercise load and blood flow is directed away from the gut. Most gels deliver between 20–30 g of carbohydrate per serving, typically from a blend of different sugar types to take advantage of separate intestinal transport pathways and maximise absorption rate.
The primary ingredients found across most energy gels include:
- Carbohydrates — the core of every gel. Combinations of glucose (or maltodextrin) and fructose are now standard in high-performance formulations, as they use different absorption mechanisms and allow higher total carbohydrate uptake per hour compared to single-source gels.
- Electrolytes — sodium in particular helps maintain fluid balance and supports nerve and muscle function. Potassium and magnesium are included in some formulas, especially those designed for longer efforts or warm-weather use.
- Caffeine — included in a subset of gels to support alertness, reduce perceived exertion, and provide a secondary performance boost. Typically dosed between 25–75 mg per serving.
- B vitamins — present in some gels to support energy metabolism, alongside vitamin C in formulations that also target antioxidant support during exercise.
Types of Energy Gels — How to Choose
Standard Isotonic Gels
Isotonic gels are formulated to match the osmolarity of body fluids, meaning they can be taken without additional water — a significant practical advantage for runners and cyclists who want to minimise logistical complexity. The carbohydrate concentration is lower per gram of gel, but absorption is very efficient. SIS GO Isotonic gels are the best-known example of this category: designed specifically so that no water is needed alongside the gel, they are among the most gut-friendly options available and are well suited to runners who find concentrated gels cause discomfort.
High-Carbohydrate Performance Gels
For athletes working at high intensities or targeting maximum carbohydrate delivery per hour (90 g/hr is the commonly cited upper limit achievable with glucose:fructose blends), more concentrated gels with dual-source carbohydrate formulations are the right choice. The SIS Beta Fuel + Nootropics gel uses a 1:0.8 maltodextrin-to-fructose ratio specifically to optimise oxidation rates, and also includes nootropic ingredients for cognitive support during long efforts. These gels should always be taken with water.
Caffeinated Gels
Caffeinated gels are best used strategically — not throughout an entire event, but at specific moments where a boost in alertness or motivation is needed: the final third of a long run, a demanding climb in a sportive, or when fatigue begins setting in. Nutrend Carbosnack Gel with Caffeine provides a cola-flavoured option with added caffeine, suitable for mid-effort use. If you are sensitive to caffeine or training in the evening, caffeine-free alternatives are the better choice.
Chews and Gummy Formats
Some athletes find liquid-consistency gels harder to take during hard breathing. PowerBar PowerGel Shots — chewable gummy pieces rather than a squeezable gel — offer the same fast-release carbohydrate delivery in a format that some find more manageable. They are also easier to portion across a longer session.
[tip:Always practise with gels in training before using them in a race. Gut tolerance to gels during hard exercise is individual and can take several sessions to establish. Never try a new product or flavour for the first time on race day.] [products:sis-go-isotonic-energy-apple-60-ml, sis-beta-fuel-nootropics-energy-gel-apple-60-ml, powerbar-powergel-original-blackcurrant-41-g, powerbar-powergel-hydro-cherry-67-ml, nutrend-carbosnack-gel-with-caffeine-cola-50-g, powerbar-powergel-shots-gums-orange-60-g]Timing and Dosage Guidelines
For sessions under 60 minutes at moderate intensity, energy gels are generally unnecessary — the body's pre-exercise glycogen stores are sufficient. For efforts lasting 60–90 minutes at higher intensities, a single gel taken around 45 minutes in can help sustain output. For sessions beyond 90 minutes — long runs, cycling sportives, triathlons — a standard approach is to take one gel every 30–45 minutes from roughly 30–45 minutes into the effort, always accompanying standard concentrated gels with approximately 150–200 ml of water.
Pre-race, a gel taken 10–20 minutes before the start is a common strategy for topping up glycogen and ensuring readily available carbohydrate at the gun, particularly if the pre-race meal was more than 2–3 hours earlier. Individual response varies, so test this in training first.
Gels are a powerful tool, but they work best as part of a structured race nutrition plan rather than consumed reactively when fatigue hits. By the time you feel the onset of bonking, blood glucose has already dropped — staying ahead of energy demands is the key principle.
Beyond Gels — Complementary Sports Nutrition
Gels address in-session carbohydrate needs, but endurance performance draws on a broader nutritional foundation. Isotonic drinks handle hydration and electrolyte replenishment simultaneously, making them the natural partner to gel-based fuelling — especially in longer events or warm conditions. Beetroot shots, such as those from Beet It Sport, are used in the hours before exercise: the dietary nitrates they contain convert to nitric oxide in the body, supporting blood flow and oxygen efficiency during sub-maximal efforts. Tart cherry (Active Edge CherryActive) is increasingly used post-effort for its anthocyanin content, which may support recovery from exercise-induced muscle damage.
Explore our full energy gels collection and isotonic drinks for the complete range of in-session fuelling options. For broader sports nutrition planning, visit our sports nutrition collection.
[products:beet-it-sport-nitrate-400-beetroot-shot-70-ml, beet-it-sport-regen-cherry-shot-70-ml, active-edge-cherry-active-tart-cherry-juice-473-ml, nutrend-carbosnack-gel-lemon-50-g, trec-endurance-energy-gel-forest-fruits-40-g, biotech-usa-energy-gel-pro-orange-40-g] [note:All products available at Medpak ship from within the EU — no customs delays or additional import fees for customers across Europe.]
