To use an energy gel effectively, take it before you feel depleted — typically 30–90 minutes into exercise — and follow it with a few sips of water unless the package says otherwise.
Energy gels aren’t complicated, but getting the timing right separates a smooth run from a mid-race bonk. A gel delivers a fast-release hit of carbs — most contain 22–30 g per packet — designed to reach your bloodstream quickly when you’re sweating hard. The trick is starting early, staying on schedule, and matching the product to your event length and stomach tolerance. Below is everything you need to know about when to take them, how to take them, and how to avoid the mistakes that send runners to the porta-potty.
How to Take an Energy Gel: The Simple Mechanics
Open the sachet by tearing the top notch (most brands include a tear-point), squeeze the gel directly into your mouth, and swallow. There’s no chewing, no mixing — just quick fuel. Science in Sport (SIS) describes the process as “tear off the top and squeeze the gel into your mouth,” which is exactly as easy as it sounds.
For standard gels, drinking water immediately after helps thin the gel for faster absorption and lowers the chance of stomach upset. One major exception: hydrogel formulas, such as SIS’s GO Isotonic range, are designed to work without additional water. If you’re on a course with sparse aid stations, these can be a game-changer.
If you’re serious about endurance cycling and want help choosing between brands, our tested roundup of the best energy gels for cycling ranks the top performers by carb content, flavor, and race-day reliability.
When Should You Take an Energy Gel?
The single most consistent piece of advice from sports-nutrition sources is: don’t wait until you need it. By the time you feel weak, your blood sugar has already dropped. Start fueling before the fatigue sets in.
For most endurance efforts:
- Under 60 minutes: No gel needed. Your body has enough stored glycogen for this duration.
- 60–90 minutes: One gel taken around the 30–45 minute mark can help maintain pace.
- 90+ minutes: Start your first gel 30–60 minutes in, then repeat every 30–45 minutes for the duration. Runners World suggests taking the first running gel 60–90 minutes into the effort, then following with one every 30–45 minutes thereafter.
The carbohydrate target varies by event length. For runs of 1–2.5 hours, aim for 30–60 g of carbs per hour. For events longer than 2.5 hours, push that to 60–90 g per hour if your stomach can handle it. Since most gels contain roughly 22–30 g of carbs, a 60–90 g target means 2–3 gels per hour for longer efforts. SIS explicitly recommends 1–3+ gels per hour to hit that 60–90 g range.
Common Mistakes That Ruin a Gel Strategy
Even experienced athletes fall into these traps. Here are the ones to avoid:
- Using a new gel on race day. Test any brand, flavor, or caffeine content during training. Race-day surprises can hit hard.
- Skipping water with a standard gel. Without water, the concentrated sugar can sit in your stomach and cause nausea or cramping.
- Taking too many at once. One gel every 30 minutes is better than two gels every hour. For sensitive stomachs, some athletes split a single gel into quarter portions across 30 minutes.
- Ignoring the carb-per-hour target. If you’re in a marathon and only take one gel at mile 10, you’ll run out of fuel by mile 18. Match the frequency to the event length.
- Using caffeinated gels too early. Many experts recommend saving caffeine gels for the second half of an event, when the stimulant boost is most useful.
Choosing the Right Gel for Your Effort
Not all gels are identical. SIS breaks its lineup into roles: the GO Isotonic gel is the base fuel for general use; GO + Caffeine (75 mg or 150 mg) adds a stimulant boost; GO + Electrolyte is formulated for heavy sweating or hot conditions; and Beta Fuel is a higher-carb (80–120 g/hour) option for events beyond two hours. Picking the wrong formula for your conditions can hurt performance — or your stomach.
Caffeine gels are generally best saved for the second half of an event. If you’re running in heat or sweating heavily, an electrolyte blend helps replace what you lose. Avoid experimenting with any of these on race day; train with the same flavor and caffeine level you plan to use.
References & Sources
- Science in Sport. “Energy Gels — Recommended Use.” Official guidance on timing, carb targets, and product categories.
- Science in Sport. “The Definitive Guide to Energy Gels.” In-depth advice on fuel strategy, product selection, and common mistakes.
- Runner’s World. “How to Train with Gels in Training and Racing.” Practical tips on timing and gut training from a major running publication.