When I first started marathon training, I thought energy gels were optional, something for ultra-runners or people doing Ironmans in the desert. But after a few humbling bonks around mile 17, I learned otherwise. Gels are essential. They’re one of the few tools you can carry in your pocket that actually make a difference mid-race.
At their core, gels are concentrated carbohydrate sources, usually about 20–25 grams per packet, designed to quickly replenish glycogen stores and keep your brain firing when energy dips. They’re small, portable, and easy to take while running, which makes them the most practical mid-run fuel option for marathoners. Most also contain electrolytes, which help offset what you’re sweating out. Some add caffeine for an extra boost.
Personally, I don’t use caffeinated gels. I’ve found my system runs better on steady, predictable inputs, not spikes. But it’s worth understanding the differences so you can make the right call for your own race plan.
Caffeinated gels are popular for good reason. Caffeine is a proven performance enhancer. It can reduce perceived effort, sharpen focus, and even increase fat oxidation (which can spare glycogen for later in the race). For some runners, that makes the last 10K feel a little less impossible. But there’s a downside. Caffeine is also a diuretic, a gastrointestinal irritant, and a stimulant. It can cause jitters, stomach issues, or an unpleasant crash if your body isn’t used to it. If you already rely on coffee for daily function, you might handle it well. But if you’re not used to caffeine, race day isn’t the time to experiment.
Regular gels, caffeine-free, tend to be easier on the stomach and more predictable. You know what you’re getting, and that consistency matters when your body’s under stress. That’s why I’ve stuck with Huma and Maurten.
Huma gels are fruit-based, made with chia seeds, and feel more “real food” than most gels. They sit light, taste clean, and include electrolytes. I use them often in training when I want something easy on the stomach that still gets the job done. Maurten, on the other hand, is science in a pouch. It uses a hydrogel delivery system that allows you to absorb more carbs with less gut distress. It’s become the go-to for elite marathoners for a reason, high fuel intake, minimal disruption. On race day, I lean toward Maurten because I want maximum efficiency with zero surprises.
It took me years of trial and error to figure out the right mix and timing. I’ve tried nearly every brand, misjudged fuel timing more times than I’d like to admit, and learned the hard way that “waiting until you feel tired” is not a fueling strategy. Now, I take one gel every 40 minutes during the marathon. That might sound early, but here’s the science: your body starts burning through glycogen almost immediately. If you wait until you're fading, you’re already behind. Starting your gel routine in the first 30–45 minutes keeps your energy steady and prevents the dreaded crash.
There’s no one-size-fits-all gel plan, but you do need a plan. Figure it out before race day. Try different brands, test the timing, and listen to your body. Gels may not be glamorous, but they’re the difference between hanging on and finishing strong.
And trust me, strong feels a lot better.