Lauren HollandBy Lauren Holland

Updated November 2026

You should use energy gels when running efforts last longer than about 60 to 90 minutes, when you are running hard enough that your body is burning through stored glycogen, or when you plan to run long enough that food alone won’t cover your fuel needs. For most runners, that means starting gels around the 45- to 60-minute mark of a long run or race, then taking one every 30 to 45 minutes after that.

Why timing matters more than the gel itself

Your body stores roughly 300 to 500 grams of carbohydrate as glycogen, split between your liver and muscles. Depending on your size, fitness and pace, that supply can run low somewhere between 90 minutes and two hours of steady running. When it does, you feel it as heavy legs, a sudden drop in pace, and the mental fog runners call “bonking.” Taking a gel before that point keeps carbohydrate flowing into your bloodstream and muscles so your pace holds.

Shopping for one? See our guide: 6 Best How Oftens to Take Energy Gels When Running (2026): Our Picks.

Starting too late is a common mistake. By the time you feel depleted, your gut is already working against you, because digestion slows under hard effort and blood flow is pulled toward your legs. Starting early, while you still feel fine, gives your body time to absorb what you take in.

Factors that change when you should take a gel

No single timing rule fits everyone. A few variables shift the window:

  • Pace and intensity. Running at marathon effort burns carbohydrate faster than an easy jog. A 10-mile run at a conversational pace may need no gels at all, while the same distance at tempo effort may need one or two.
  • Duration. Under 60 minutes, most runners can go without. Between 60 and 90 minutes, one gel is often enough. Beyond two hours, a steady schedule becomes necessary.
  • Your pre-run fueling. If you ate a substantial, carbohydrate-rich breakfast two to three hours before the start, your glycogen stores will be fuller and you can delay the first gel slightly.
  • Heat and humidity. Hot conditions raise your effort and fluid needs, so you may want to start a little earlier and pair gels with water or an electrolyte drink.
  • Your gut tolerance. Some runners handle gels easily from the first mile, while others need to build tolerance through training. Practice is the only reliable way to know.

How to build a gel schedule that works

Most sports nutrition guidance suggests aiming for roughly 30 to 60 grams of carbohydrate per hour during efforts longer than 90 minutes, with the higher end for trained runners who have practiced their fueling. Many common gels contain around 20 to 25 grams of carbohydrate per packet, and some concentrated versions contain about 40 grams, so check the label before you plan your schedule. Take the gel with water, not on an empty stomach if you can avoid it, and follow it with a few sips of water to help digestion.

Practical steps

  1. Eat a carbohydrate-focused meal two to three hours before your long run or race.
  2. Plan your first gel for 45 to 60 minutes into the effort, before you feel tired.
  3. Set a watch or timer to repeat every 30 to 45 minutes after that.
  4. Carry your gels in a belt or pocket you have trained with, so you are not fumbling at mile 14.
  5. Test your exact race-day plan on at least two or three long training runs.
  6. Drink water at aid stations or with your gels, but avoid large volumes of plain water on their own, since that can dilute sodium levels.

Common timing mistakes

The most frequent error is waiting until you feel bad. Other mistakes include taking every gel at once, skipping practice runs and trying a new brand on race day, and ignoring how the heat changes your needs. Each of these can lead to cramps, nausea or a fading finish, all of which are avoidable with a planned schedule.

If you have a medical condition, are pregnant, or have a history of digestive problems, speak with a doctor or registered dietitian before changing your fueling plan.

Should I take an energy gel before a run?

For most short runs, no. A light carbohydrate snack 30 to 60 minutes before is usually enough. Save gels for efforts that push past about 60 to 90 minutes, and read more in Energy Gels Before Running: When to Take Them and How Much.

How many energy gels should I take in a marathon?

Many marathoners take between three and five gels across the race, spaced roughly every 30 to 45 minutes after the first one. Your exact number depends on your pace and gel carbohydrate content. Compare options in Top 6 Marathon Running Energy Gels for Race Day Fueling.

When should I take gels during a half marathon?

Many half-marathon runners take one gel around the 45- to 60-minute mark, and another near the 90-minute mark if they are still running hard. See When to Take Energy Gels During Half Marathon: A Step-by-Step Timing Guide.

Can I take energy gels without water?

You can, but most gels are designed to be taken with some water to aid digestion. Sip water after each gel, and practice this during training so your stomach knows what to expect.

Do energy gels expire?

Yes. Check the best-by date and inspect the packet before use. Learn more in How Long Do Energy Gels Last? Shelf Life, Expiry Signs and Safe Use.

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Lauren Holland

About Lauren Holland

Lauren Holland is part of our editorial team and reviews and edits our marathon & half-marathon guides, checking product details against manufacturer specifications and owner feedback.