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What’s Really in Your Energy Gel? A Deep Dive into the Science

It might not be all it's promising.

If you’ve ever run a marathon, taken on a long trail run, or any other ultra-endurance feat, chances are you’ve relied on energy gels to keep you moving. They’re portable, convenient, and packed with carbs—at least, that’s what all the labels claim. But how much can you trust those labels? A new study might make you think twice.

Researchers recently analyzed eight popular brands of energy gels—names you’d recognize if you’ve ever wandered the nutrition aisle at a running store. They wanted to see if the energy and nutrient content lived up to the promises on the packaging.

Spoiler alert: one brand didn’t exactly make the cut.

What’s Really in Your Energy Gel? A Deep Dive into the Science 1

The Good, the Bad, and the Gels

Now, you likely don’t need to stress too much, as most of the tested gels performed well enough. Brands like Gu Energy, Honey Stinger, Maurten, and Science in Sport were mostly accurate in their claims.

However when it came to Spring Energy’s Awesome Sauce (yes, that’s the real name), things got a bit… less awesome. The lab results showed it had 71% less energy and 72% less carbohydrates than advertised. For athletes depending on these numbers during a race, that’s a recipe for bonking—big time.

To dig deeper, researchers tested multiple lots of Spring Energy products. The trend continued: lower-than-expected carbs, calories, and even sodium—a crucial electrolyte for endurance athletes. If you’re fueling for a marathon or ultramarathon with these gels, you could be taking in far less than you need to stay energized and hydrated.

How Your Favorite Gels Stacked Up

Seven out of the eight gels tested were mostly accurate in their energy and carbohydrate content. Gu Energy, Honey Stinger, Maurten, Hüma, Näak, Precision Fuel, and Science in Sport (SiS) all measured within 20% of the values stated on their labels, which is the threshold allowed by international regulations.

Here’s a quick breakdown of their performance:

  • Gu Energy: Consistently accurate, delivering on both carbohydrate and calorie content.
  • Honey Stinger: Slightly under the stated numbers but still within acceptable limits.
  • Maurten: Nailed the consistency, with measurements matching almost exactly to the label.
  • Hüma and Näak: These gels showed small discrepancies, but nothing that would drastically impact performance.
  • Precision Fuel and SiS: Delivered reliable results, making them solid choices for fueling strategies.
What’s Really in Your Energy Gel? A Deep Dive into the Science 2

The Spring Energy Debacle

Now, if you’ve spent any time in the endurance world, Spring Energy or Awesome Sauce might be sounding familiar. That’s because earlier this year, Spring Energy was in the hot seat after it was discovered their products contained way less carbs and energy than their labels claimed

Spring Energy, a (somehow) still-standing boutique sport nutrition brand based in San Fransisco, was called out back in June by the respected ultra coach and podcaster Jason Koop for creating what he claimed is a “fraudulent” product. This came following months of speculation within the ultra community that something wasn’t quite right with the company’s popular “Awesomesauce” line of gels.

Koop revealed in a series of Instagram Reels that he’d grown suspicious of Spring Energy’s claims that its gels contained a significant amount of calories and carbohydrates, after he noted that a group of runners had posted on Reddit about their concerns with the product.

So Koop decided to buy a bunch of the Awesomesauce gels and ship them to a third-party lab for testing. And the results were damning.

You can watch Koop’s entire monologue on his findings below:

Spring Energy claims that each Awesomesauce Energy Gel contains a whopping 180 calories and 45g of carbs. This is an attractive package for ultrarunners looking to stave off a caloric deficit, which, as Koop points out, will make or break a race over time. For recreational ultrarunners, it could mean the difference between success and failure after months of hard work. For elite athletes, it could have huge negative consequences on their career if they inexplicably fall apart mid-race. And for all athletes, Koop notes, a misinformed nutrition plan on the trails could lead to a serious health crisis for some.

And at $4.80 a pop, you’d hope to get what you’re paying for from an Awesomesauce gel.

When Koop got the lab analysis result, it showed that each 54g serving contained only 75 calories and 18g of carbs, less than half of what the packaging claims.

YouTube video

Why This All Matters

This isn’t just a numbers game; the discrepancies could have real consequences. Imagine following a race plan that calls for two gels an hour, expecting 90 grams of carbs and 360 calories. With the Spring Energy gel, you’d actually be getting just 30 grams of carbs and 144 calories. That’s a massive shortfall, enough to lead to early fatigue or even hypoglycemia (low blood sugar).

For athletes tackling long or hot races, the lack of sodium could also spell trouble. Sodium plays a key role in hydration and preventing conditions like hyponatremia, a potentially life-threatening drop in blood sodium levels. And for people with diabetes who rely on precise carbohydrate amounts to manage their blood sugar, inaccurate labels aren’t just inconvenient—they’re dangerous.

Spring Energy has since reformulated its products, addressing issues in its production process. But the study serves as a wake-up call for all athletes: not every label tells the full story. It’s a reminder to stay informed and, when possible, test how products work for you during training—not just on race day.

If you’re using gels regularly, it might be worth paying extra attention to how you feel during workouts. Are you hitting the wall sooner than expected? Feeling hungrier than usual? Those could be signs your nutrition isn’t matching your needs. And if in doubt, consult with a nutritionist or try a different product to find what works best for your body.

1 thought on “What’s Really in Your Energy Gel? A Deep Dive into the Science”

  1. I’m “old school’ in my thoughts and experiences with training and racing. I’m 82 yrs. old and ran my 2:35;53 marathon PB in Boston in 1981. After 60 years of running, having run my last marathon in 2002 in Chicago, I never used energy gels or any of the controversial stimulants that seem to be in vogue with todays’ runners. I believe success in performance still boils down to the training plan you follow and a proper diet, including complex carbohydrates. There are no short cuts to achieve performance, just hard work.

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Jessy Carveth

Senior News Editor

Jessy has been active her whole life, competing in cross-country, track running, and soccer throughout her undergrad. She pivoted to road cycling after completing her Bachelor of Kinesiology with Nutrition from Acadia University. Jessy is currently a professional road cyclist living and training in Spain.

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