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Comparison summary of SiS Go, Maurten Gel 100, and Huma Original: Huma is best suited for athletes that enjoy fruit flavors and prefer natural ingredients. Maurten’s milder sweetness is an ideal option for marathoners that want to stick with a single brand for the entire race but beware of its high price. SiS isotonic energy gels have a pleasant flavor but best suited for training due to its larger sachet. 


Balancing between fueling sufficiently and not overwhelming your digestive system is one of the key factors determining race-day performance.

Not fueling enough could mean smacking head-first against the dreaded “wall.” On the other hand, an over-aggressive fueling plan that stresses your stomach will likely get you a date with the porta-potty mid-run. Either way, you can say buh-bye to a PB. It’s a fine line.

Energy gel makers have explored various product design philosophies to provide the nutrition your body needs, in the proper amount and via the most efficient physiological pathways.

Today, let’s look at three energy gels with stomach-friendly reputations – SiS Go Isotonic Energy Gel, Maurten Gel 100, and Huma Original. We have used them extensively over the years and can attest to their performance regarding delivering energy free of stomach stress.


Why does an upset stomach occur during exercise?

Before beginning the energy gel comparison, we want to briefly explain why stomach issues are common during endurance athletics.

In super-duper layman’s terms, an upset stomach occurs when food or fluids in your digestive system are not processed correctly.

During a race, three integral systems – muscles, digestion, and cooling – constantly fight for your blood. With resources diverted to maintain muscle function and body temperature, your stomach isn’t at an optimum state, to begin with, and now you ingest dose after dose of sugary, syrupy concoction? You do the math.

Huma Original – all-natural ingredients, including chia seeds

Does the source of sugars matter? There are two schools:

  1. Sugar is sugar. Your body will metabolize it into glycogen regardless of the source.
  2. Natural over artificial. The production process of synthetic carbohydrates differs from how nature does it. Your body may react less favorably to artificial ingredients, so nutrients from natural sources are more bioavailable and healthier.

As the self-proclaimed best-selling, all-natural energy gel, Huma certainly epitomizes the latter. The company calls its products the stomach happy gels, incorporating only natural ingredients, including the popular superfood chia seeds. Its core marketing message? Natural ingredients are the gentlest on our digestive system.

Here are the ingredient list and nutritional facts of one of its flavors.

The carbohydrate sources are fruit puree (fructose), cane sugar (sucrose), and brown rice syrup (glucose), sugar from natural sources as advertised. The energy gel also provides 1-2 g of dietary fiber, which should theoretically slow sugar absorption, help you avoid big blood sugar spikes and crashes, and make it easier on your digestive system.

What are the pros and cons of Huma Orginal energy gel?

Let’s start with the good. Pros:

  • We tested Huma Original in a 25 km progression session and can attest that it delivered consistent energy.
  • It has a light, fruity flavor that’s good for hotter temperatures. The product series includes eight flavors for a nice variety.
  • There was no notable “surge” after intake, which I used to think was a bad thing, but I have since learned that surges are likely associated with a spike in blood sugar. What goes up must come down. I now much prefer a stable, slower-reacting fueling experience.


  1. The sachet is big since it’s a 40+ g energy gel. Make sure it fits in your fuel-carrying gears.
  2. This is not a real con, but I thought it’s gimmicky. While the company doesn’t specify how much chia seeds are used, the superfood is listed fourth or fifth on the ingredient lists. I don’t know if there are enough to be genuinely beneficial.
  3. Due to the milled chia seeds, the gel seems to have a bit of oil. So pay attention to expiration dates and store them in cool environments.


Maurten Gel 100 – the pioneer of hydrogel

This relatively young brand was founded with the mission of solving gastrointestinal distress. According to Maurten, carbohydrates encapsulated in a hydrogel can bypass the stomach to the intestines, where they can be absorbed faster without causing gastrointestinal distress.

The digestive system consists of the gastrointestinal tract (mouth, esophagus, stomach, small intestine, large intestine, and anus), liver, pancreas, and gallbladder. Each organ moves food and fluids along, processes food and drinks into absorbable components, or distributes nutrients to various parts of the body. 

By skipping the stomach, Maurten simplified the absorption protocol to eliminate some possible complications during digestion. We have tested Maurten Gel 100 extensively in a mountain ultra, marathons, and workouts, as well as the brand’s Drink Mix, if you are interested in learning more.

Here are the ingredients and nutritional facts of Maurten Gel 100

  • Water
  • Glucose
  • Fructose
  • Calcium Carbonate
  • Gluconic acid
  • Sodium Alginate


40 g sachet provides the following:

  • 100 calories
  • Carbohydrate 25 g
  • Fat 0 g
  • Protein 0 g
  • Sodium 35 mg
  • Calcium 21.6 mg

Many energy gels in the market consist of at least ten to twenty ingredients with added flavoring, preservatives, and other nutrients. Looking at Maurten’s six listed ingredients, it’s pretty much just sugar, salt, and thickeners.

What are the pros and cons of Maurten Gel 100?


  • I give Maurten Gel 100 two thumbs up regarding taste and consistency. Instead of adding more flavoring, Maurten provides a neutral taste that made its energy gels more tasteless and less sweet. Due to the hydrogel, the texture is like a not quite completely set jello.
  • 100 calories and 25 g of carbohydrates, a generous dose of energy
  • The milder taste makes it easier to consume multiple packs without taste fatigue.


  • It’s pricey. The cost could add up if you use it regularly for training. USD 43.5 for a box of 12 Gel100 and USD 50 for a box of Caf100.
  • Despite all the technological bells and whistles, there was no noticeable “feelings” compared with other gels regarding energy delivery. But it did its job, providing consistent energy without bad taste and stomach issues.

SiS Go Isotonic Energy Gel – no water needed

Isotonic solution: A solution with the same salt concentration as cells and blood. It’s used as intravenously infused fluids in medical patients.

UK-based Science in Sport (SiS) developed its isotonic formula in 2002. The technology “allows the gels to empty from the stomach quickly as no fluid needs to be drawn into your stomach to dilute the gel, providing fast energy.

Conventional energy gels are essentially highly concentrated sugar water, which requires water to break down. If you don’t drink enough fluids, your body needs to draw water from the gastrointestinal tract to assist digestion, compromising the entire system. However, overdrinking can also be problematic because it lowers your body’s electrolyte concentration. With SiS Go’s isotonic formula, you don’t need water to chase down the gels, the company claims.

We tested the energy gel on a mountain road run on a hot summer day. It was effective and fueled the lengthy session with zero stomach issues.

Here are the nutritional facts and ingredients of SiS Go Isotonic Energy Gel.

The majority of the carbohydrates come from maltodextrin. Compared with other sugars, it requires less water to digest. It is an excellent way to get quick calories without dehydrating.

What are the pros and cons of SiS Isotonic Go Energy Gel?


  • A mild sweetness and a watery texture deliver a pleasant option, like thickened, fruit-flavored water. Comes in ten flavors.
  • You can definitely feel that it’s light and easy on your body.
  • If you’re starting a run well-hydrated, you can leave your water bottle at home.


  • At 60 ml, it provides only 87 calories and 22g of carbohydrates. Not a lot of energy for such a big sachet.
  • The packaging is big. It may not fit in some pockets of your running shorts and hydration vest.
  • Despite the fast-reacting hype of its isotonic formula, no significant difference regarding mouth-to-muscle time. But again, not necessarily a bad thing.



Above are three pathways to solving gastrointestinal issues connected to endurance sports fueling. We are comfortable recommending them for endurance athletes that have sensitive stomachs. However, their packaging, flavors, and form factors make them suitable for different purposes.

Huma Original
If you enjoy fruit flavors, Huma could be the choice for you. As a reviewer, we can’t say we’ve tried them all, but Huma does a good fruity energy gel.

The big sachet is reasonably flat, so it’s not too bulky to carry. Just make sure it fits in your shorts and vest pockets. For multiple-hour adventures in high temperatures (ultras, for example), Huma is ideal to keep you topped up and ready to grind.

Maurten Gel 100 Hydrogel
If you like to keep things simple and just stick with one energy gel brand for an entire run or race, we recommend Maurten Gel 100. Its mild taste allowed us to eat 6-7 packs for marathons without overwhelming taste fatigue.

It also provides the best bang for the size out of the three options, delivering 25 g of carbohydrates per pack at a relatively small pack. We recommend Maurten as the best energy gel for marathons if price isn’t a factor for you.

SiS Go Isotonic Energy Gels Energy
If you are out for a 1-2-hours and don’t want to carry a water bottle but still want to fuel, SiS isotonic gels are excellent – pleasant taste and easy on your stomach. However, the lower caloric and carbohydrate content for such a huge 60 ml sachet just isn’t the best option for races when you want to feel light and fast.