Comparison of Energy Gels
Energy gels are a useful component of many endurance runners' training and racing. In marathon distance racing, energy gels can make an important difference - When to eat Energy Gels in the Marathon.
1 Gel Ingredients
Here is an overview of the major ingredients in gels (see The Science of Energy Gels for more details).
- Maltodextrin is the most easily digested form of carbohydrate, 36% faster than glucose, making it ideal in a gel. More importantly, Maltodextrin requires far less water to be isotonic than glucose or Fructose. Maltodextrin has little or no flavor, even at high concentrations.
- Glucose is easily digested, but requires 6 times as much water as Maltodextrin to be isotonic. Glucose is about three quarters as sweet as sugar (sucrose).
- Note that 97% of brown rice syrup is a mixture of maltose, which is 2 glucose molecules and maltotriose which is 3 glucose molecules. For practical purposes it can be considered the same as glucose, though possibly contaminated with arsenic.
- A little bit of Fructose is useful, as Fructose is absorbed via different pathways, increasing the total carbohydrate absorption above what is possible with Maltodextrin alone. However, too much Fructose will cause digestive problems and Fructose is absorbed at about a forth the rate of glucose. It also requires the same amount of water as glucose to be isotonic. Fructose is 1.7x as sweet as sugar (sucrose).
- Sugar is a cheap ingredient and is half glucose and half Fructose.
- Fat can make a gel more palatable and is a useful fuel source at ultramarathon distances.
- Some protein can provide an additional fuel source and help limit the tendency of your body to cannibalize muscle for fuel.
- Amino acids may help performance, but the evidence is unclear at the levels provided in most gels.
- Caffeine is great for improving performance and speeding the absorption of carbohydrate, but too much can upset the stomach.
- Flavor is important, as you won't want to take an unpalatable gel. Experiment with different flavors, as different people have different tastes, and what flavor appeals can vary with circumstance.
This table is a combination of the science of nutrition, personal experience and the experience of many runners I've talked to, with more details given below.
| Other Carbs1
| Water to
be Isotonice (ml)
|Carbs/g||Cal/g|| Ease of digestion
(higher is better)
|Hammer Gel||90||23||2||21||1||1||0||0||0||20||0||0/25/50||103||33||0.70||2.73||10||38||Sensitive Stomachs|
|SIS Isotonic||86||22||0.6||21.4||0.6||0||0||0||0||10||0||0||47||60||0.37||1.43||10||1||Light, easy to digest, but big|
|Carb BOOM||110||27||3||24||1.5||1.5||0||0||0||50||50||0/50||145||41||0.66||2.68||9||16||Hammer Alternative|
|Gu Roctane||100||25||5||20||0||5||0||1.7||0||125||55||0/35||164||32||0.63||3.13||8||62||Those looking for every advantage|
|Gu (Peanut Butter)||100||20||5||15||0||5||0||1||1.5||65||60||0||201||32||0.78||3.13||7||4,290||A less sweet Gu|
|Vi Endurance||100||23||6||17||6||0||0||0||1||10||15||10||168||32||0.72||3.13||7||17||Fructose malabsorption|
|Clif Shot (new formula)||100||24||12||12||6||6||0||0||0g||90||50||0/25/50/100||292||34||0.71||2.94||6||96||A Gu Alternative|
|USN Vooma Energy||100||23.8||7.9||15.9||5.4||2.5||0||0||0||100||50||30||228||36||0.66||2.78||6||2||A Gu Alternative|
|PowerBar Gel||110||27||10||17||0||10||0||0||0g||200||20||0/25/50||293||41||0.66||2.68||5||5||Those needing extra electrolytes|
|eGel||150||37||7||30||0||7||0||0||0||230||85||0||295||55||0.67||2.73||5||20||A PowerBar Gel Alternative|
|High5 EnergyGel||92||23||3||20||2||1||0||0||0||20||0||0||122||30||0.77||3.07||5||0||A Gu Alternative|
|Accel Gel||100||20||13||7||4||9||0||5||0||115||30||0/20||297||37||0.54||2.70||4||32||Improved Recovery and Ultradistances|
|Honey Stinger||120||29||29||0||14||15||0||0||0||50||85||0/32||572||37||0.78||3.24||2||12||Not Recommended|
|Chocolate #9||70||15||13||0||3||10b||2||1||1||75||0||0||256||30||0.50||2.33||2||100,000+||Not Generally Recommended|
|2nd Surge||90||18||13||0||7c||6c||5c||3||0||115||15||100||274||30||0.60||3.00||0||9||Not Recommended|
|Chia Surge||75||17||11||6||11||0||0||0||1||4||26||0||215||37||0.46||2.03||0||335||Not Recommended|
- a These values are estimates based on the stated nutrition and ingredients.
- bAgave nectar varies in its Fructose content between 90% and 55%, so this calculation assumes the average of about 75%.
- cThe unusual nature of the ingredients in 2nd surge makes it harder to estimate the types of carbohydrates included.
- dThe sugar value includes sucrose, Fructose, glucose and other 'sugars'.
- eThis is an approximation based on the amount of sugar, Maltodextrin, sodium and potassium, ignoring other ingredients. The water included in the gel is assumed to be the overall weight less the weight of the carbs, fat and Protein. See The Science of Energy Gels for details on the isotonic calculations.
- fThis is the net weight of the gel; generally the packaging added 2-3g to the gels according to my scales.
- gThe chocolate flavor has 1.5g
- hThe chocolate flavor has 2g
- IViscosity, or thickness, varies enormously between gels. The thickest, Chocolate #9 is more like a paste than a gel, were the thinnest, PowerBar Gel is a liquid.
3 Visual Comparison
4 Hammer Gel
Hammer Gel is noteworthy as one of the easiest to digest gels. It is nearly all Maltodextrin dissolved in a greater volume of fluid than other gels. The low level of sugars and electrolytes makes this far easier on the digestive system, and is recommended for runners who have issues with other types of gel. Note the low level of Fructose, which makes the maximum carbohydrate absorption lower than other gels. Therefore use Hammer only if Gu is difficult to digest.
Ingredients (Vanilla): Maltodextrin, Filtered Water, Energy Smart (Grape juice and Rice dextrins), Potassium Sorbate (as a preservative), Vanilla Extract, Citric Acid, Potassium Chloride, Salt, Amino Acids (L-Leucine, L-Alanine, L-Valine, L-Isoleucine).
5 SIS GO Isotonic
This gel is rather different to most others on the market, and in many ways it's more of a small drink than a gel. The packet is roughly twice as big as most standard gels, which makes it awkward to carry. The flavor is extremely light and I would almost describe it as bland. This is a gel that's worth considering if you're having problems digesting more mainstream gels or if you want something with little or no flavor, and you don't mind carrying the bulk. (Note that this gel is generally only available in Europe.)
Ingredients (Orange): Water, Maltodextrin, Natural Flavoring, Gelling Agents (XanthanGum, Gellan Gum), Acidity Regulators(Citric Acid, Sodium Citrate),Preservatives (Sodium Benzoate, Potassium Sorbate), Sweetener (AcesulfameK), Sodium Chloride, Antioxidant (Ascorbic Acid), Color (Beta-Carotene.
6 Carb BOOM
Carb BOOM is similar to Hammer Gel. Each packet of Carb BOOM is about 25% larger than Hammer Gel, but contains similar ingredients (slightly more electrolytes). </br>Ingredients (Apple Cinnamon): Maltodextrin, Water, Apple Puree, Apple Concentrate, Citric Acid, Potassium Citrate, Sea Salt, Cinnamon, Potassium Sorbate and Sodium Benzoate.
For marathon distance racing, I prefer Gu over all other gels I've tried. You could think of Gu as the Honda Civic of energy gels; it's not perfect for everyone in every situation, but it's a great all-rounder. It contains 5g of Fructose, with the rest of the calories coming from the easily digested Maltodextrin. I find that Gu can be consumed without any extra water as long as it is taken a bit at a time and mixed with saliva. Some of the flavors can be a little strong, but the 'plain' Gu has a light cola flavor. Gu is slightly thicker than other gels, which I find makes it easier to mix the gel with saliva, but it can become overly thick in colder conditions.
Ingredients (Vanilla): Maltodextrin, water, Fructose, Gu Amino acids (leucine, valine, histidine, isoleucine), potassium and sodium citrate, antioxidants (vitamin E and C),citric acid, calcium carbonate, vanilla, sea salt, preservatives (sodium benzoate, potassium sorbate), fumaric acid, herbal blend (chamomile, kola nut, ginger), pectin.
8 Gu (Peanut Butter)
The peanut butter flavored Gu is different enough to justify its own section. The peanut butter flavor is far less sweet than the regular Gu flavors, but if you like peanut butter it can be a lot more palatable. It also substitutes a little bit of fat and Protein for the carbohydrate, as well as having a tiny bit more sodium and potassium. I find this flavor digests particularly well and I'd recommend trying get if you're a fan of peanut butter. Obviously, if you hate peanut butter or you have a peanut allergy this is not going to work for you. The Peanut Butter flavor is one of the thickest gels, and is quite a bit thicker than the other flavors of Gu. Even in warm conditions it tends to be a little too thick, and in cold conditions it can become bit like a chewy candy such as taffy, toffee, etc.
Ingredients: Maltodextrin, water, Fructose, Peanut butter (peanuts, salt), Gu Amino acids (leucine, valine, histidine, isoleucine), potassium and sodium citrate, antioxidants (vitamin E and C), preservatives (sodium benzoate, potassium sorbate), calcium carbonate, sea salt, fumaric acid, calcium chloride, pectin, citric acid, malic acid, herbal blend (chamomile, ginger).
9 Gu Roctane
Roctane is a more expensive variant on Gu, though the price has reduced significantly since its introduction. The main difference is the addition of 1.7g of amino acids, which may help slightly. Roctane is not as thick as the standard Gu. I've not noticed any difference when using it, but if you like Gu and are looking for even a slight advantage, it may be worthwhile. If you are paying hundreds of dollars for a race entry and travel, then the extra cost is minor. If you take 8 gels in a 4-hour marathon, Roctane only adds $4-5 to the cost of the race. Of course, you'll need to practice with Roctane in your training, so you'll have to factor that cost in as well.
Ingredients (Blueberry flavor): Maltodextrin, water, Fructose, Roctane Amino acids (Histidine, Leucine, Valine, Isoleucine), Ornithine Alpha-ketoglutarate (OKG), sodium citrate, malic acid, citric acid, potassium citrate, natural pomegranate flavor, natural berry flavor, calcium carbonate, sea salt, Caffeine, sodium benzoate, potassium sorbate.
10 Vi Endurance
Vi Endurance has no Fructose, so it's ideal for those that suffer from fructose malabsorption. It has a little fat in the form of Medium Chain Triglycerides, as well as some Taurine, which I think are good things, but probably the amount is not significant enough to make much of a difference. There is a little Caffeine, intended to increase the carbohydrate absorption rather than to improve performance. I found the Vi Endurance very easy on the stomach and a worthy alternative to Hammer Gel, though it's only from the manufacturer and so it a little more pricy ($1.64 with shipping.)
Ingredients (Vanilla): Maltodextrin, water, dextrose, Vi Endurance Formula (MCT Oil, Taurine, Glucuronolactone, ornithine alpha-ketoglutarate (OKG), citrulline malate, Magnesium aspartate, sodium citrate, potassium aspartate), pure vanilla flavor, potassium sorbate, sea salt, Caffeine
11 Clif Shot (new formula)
The new formula Clif Shot uses Maltodextrin like other Gels and is similar to Gu. However, it has slightly more sugar making it a little more difficult to digest. One nice thing about Clif Shots is their 'litter leash', which is a thin strip that holds the top to the body of the packet so that you're less lightly to drop the top. I found in practice that I often break the leash when opening the gels, but the idea is a noble one.
Ingredients (Vanilla): Organic Maltodextrin, Organic Sugar, Water, Natural Flavor, Sea Salt, Potassium Citrate.
12 USN Vooma Energy
Vooma has quite a strong flavor, but it is a soft, rounded flavor that I rather like. Vooma has a thinner consistency than most gels which makes it easy to swallow on the run. Overall, I've found myself looking forward to these gels more than most. (Note that this gel is generally only available in Europe.)
Ingredients (Vanilla Caramel): Water, Maltodextrin, Dextrose, Sucrose, Acidity regulators (Sodium Citrate E331i; Potassium citrate E332i), Creatine Monohydrate, Ascorbic Acid, L-Carnitine, Branched Chain Amino Acids (BCAAs)(L-Leucine, L-Valine, L-Isoleucine), Acidulant (Citric Acid), Sodium Chloride, Flavoring, Preservative (Potassium Sorbate), Glutamic Acid, Thickener (Xanthan Gum).`
13 PowerBar Gel
PowerBar Gel is noteworthy because of its higher sodium content that may help alleviate Hyponatremia and Cramps. I found the flavor stronger than Hammer, Gu or Cliff, but still quite pleasant. The level of Fructose is higher than I'd like to see for digestibility. You may need to drink some water near the time you take PowerBar Gel due to the extra electrolytes. PowerBar Gel has a noticeably thinner consistency than most other gels, and is almost a liquid. This makes it far easier to take in cold weather as it does not go so thick, but it also make it trickier to mix with saliva in your mouth.
Ingredients (vanilla): Carbohydrate blend (Maltodextrin, Fructose), water, electrolytes (sodium chloride, sodium citrate, potassium chloride), natural flavor, citric acid, sodium benzoate and potassium sorbate.
The main ingredients in eGel are close to Gu, which is no bad thing. The main differences are that eGel is twice the size of Gu, does not come in caffeinated varieties and has more electrolytes. While eGel has more electrolytes per packet than PowerBar Gel, if you take into account then PowerBar Gel has the most concentrated electrolytes. The size of eGel may appeal to some people, but I generally find the usual size more convenient. The flavors of eGel are somewhat unusual in that they taste quite sour or 'tart', possibly because of the citric acid content. Flavor is a personal thing, so if you like sour, tart tastes, then you may get on well with eGel, but I found it overwhelming. However, it's possible that eGel may be acidic enough to help with cramping. An oddity of eGel is that they contain coloring, which is strange given that most people will never actually see the gel. </br>Ingredients (Mountain Rush): Maltodextrin, Filtered Water, Fructose, Citric Acid, Sodium Citrate, Potassium Citrate, Natural Flavor, Amino Acid Blend (Leucine, Valine, Isoleucine, Histidine), Vitamin C (Ascorbic Acid), Vitamin E (Tocopherol acetate), Sodium Benzoate And Potassium Sorbate, Yellow 5, Vitamin B6
15 High5 EnergyGel
This High5 gel has a slightly sweet taste with a mild orange flavor. This light flavor makes the gel worth considering if you want to avoid the sweeter flavors that are common in other gels. High5 has a very thin, almost a liquid consistency that makes it easy to take. (Note that this gel is generally only available in Europe.)
Ingredients (Orange): Glucose, Water, Maltodextrin, Fruit Juice (min 15%, Orange/Lemon),Sea Salt, Sodium Benzoate, Potassium Sorbate
16 ISOStar Gel
This gel contains a lot of sugar, making it a little slower to digest. I found the flavor rather too sweet, and while the sweetness was offset by a strong lemon sharpness, the overall taste was a little overpowering. They claim a "Cardio Pump vasodilator", but I didn't find any supporting scientific evidence, nor did I detect any unexpected performance change when I took this gel. (Note that ISOStar is a Finnish company, and this gel is generally only available in Europe.)
Ingredients (Lemon): Wheat glucose syrup, water, natural flavouring, CARBO PUMP complex (dry extracts of apples and grapes 0.22%, vitamins C and B1), Acidifier: citric acid, preservatives: potassium sorbate and sulphur dioxide.
17 Accel Gel
I like the 4:1 carbohydrate to Protein ratio of Accel Gel, and I often use it in ultramarathon races. There is more sugar than I would like at 13g and the thin consistency makes it harder to eat slowly and mix with saliva.
Ingredients (Vanilla): Water, Fructose, Sucrose, Whey Protein Isolate and Hydrolysate, Maltodextrin, Glycerin, Natural Flavors, Salt, Ascorbic Acid, Vitamin E Acetate, Soy Lecithin.
18 Honey Stinger
Honey contains only simple sugars rather than the Maltodextrin that other Gels use. This makes Honey Stinger much harder to digest than other Gels, and much sweater. This is the one of the few Gels I've tried that has given me digestive problems when taken slowly. I also found the sweetness overpowering and unpleasant, though the honey aftertaste was quite nice. I would not recommend Honey Stinger Gels.
Ingredients (Gold flavor): Honey, Water, Potassium Citrate, Salt, Natural Flavors, Vitamins & Minerals, Niacinamide (Vit B3), Calcium Pantothenate (Vit B5), Pyridoxine, Hydrochloride (Vit B6), Riboflavin (Vit B2), Thiamine Mononitrate (Vit B1), Cyanocobalamin (Vit B12)
19 #9 Chocolate
The only ingredients in this #9 are Agave and Cocoa, and Agave is predominantly Fructose (55% Fructose to 20% glucose). This amount of Fructose is slow to be absorbed and can be difficult to digest, making it a poor choice for most runners. The Agave makes this gel intensely sweet, which I did not like and the 'processed with alkali' means that most of the antioxidants are destroyed. This is also by far the thickest gel that I've tested so far, being more like a paste than a gel. This gel may be suitable for runners that suffer from a blood sugar drop after taking more conventional gels prior to exercise (see The Science of Energy Gels for more details).
Ingredients: organic agave nectar, cocoa processed with alkali
20 2nd Surge
The ingredients in 2nd Surge are rather grim, with Agave providing Fructose and Brown Rice Syrup providing glucose (as disaccharides and trisaccharides). While this may sound better than simply using all sugar, it's chemically not an improvement, especially as Brown Rice Syrup has a bitter aftertaste and unfortunately may contain arsenic. I found that 2nd surge was overly sweet, with a slightly bitter undertones and rather gritty in texture. 2nd Surge has a higher dose of Caffeine than most gels. It's unlikely that you'd want to take a 2nd surge every 30 minutes, but if you did, you'd have 800mg of Caffeine during a four hour marathon, which is rather high. (For a 150 pound/75Kg person, that would be nearly 11mg/Kg, far more than seems prudent.) The ratio of carbohydrate to Protein can have some benefits, but it's a 6:1 ratio, rather than 4:1 which the manufacturer claims is ideal in their Accel Gel. Overall, there seems nothing to recommend these gels.
Ingredients (chocolate flavor): Agave syrup, brown rice syrup, evaporated cane sugar, water, whey Protein isolate, glycerin, pea Protein isolate, cocoa, natural flavors, green tea extract, d-alpha-tocopheryl, salt, grape, pomegranate, mangosteen, goji berry, blueberry, chokeberry, cranberry, apple and bilberry extracts.
21 Chia Surge
Chia surge is one of the more unusual gels as it contains chia seeds which give it a bitty texture. I found that these seeds got caught in my teeth, even when I tried to swallow without chewing or mixing with saliva, which was amazingly annoying. Chia surge also has relatively few calories, too much glucose, not enough Maltodextrin and almost no sodium. Chia Surge contains beta-Alanine which has been shown to improve sprint performance, though you'd likely need to take 4-12 packets a day for some days to see the benefit (see The Science of Energy Gels for more details). Overall it's hard to recommend Chia Surge. </br>Ingredients(Raspberry): Water, Dextrose, Maltodextrin, Citric Acid, Fruit And Vegetable Juice (For Color), Natural Flavors, ULS (Organic Cane Sugar, Natural Flavors, Stevia).
22 Other 'energy gels'
These products are similar to energy gels, but are not carbohydrate based.
Unlike energy gels, PocketFuel is a peanut butter like paste in an energy gel like packet. They are similar a little larger than most other gels (about 1.8oz/52g) but have far more calories (~280) due to their higher fat content. (Be careful of the nutrition label, which quotes values for a 32 gram serving, even though the packet contains 52g. The label says each packet contains "about 2" servings, but is actually 1.6 servings.) I would not generally recommend PocketFuel for runs shorter than about 40 miles, but for longer races they make a convenient form of food. Note that for some flavors the ingredients tend to settle and it's worth squishing the packet before your run to mix things up.
Ingredients (chocolate haze):Hazelnuts, almonds, sugar, cocoa powder, sunflower oil, organic palm fruit oil, sea salt.
Vespa claims to improve endurance performance by improving fat burning rather than providing fuel like other gels. The science does not seem to back this up, and they are remarkably expensive ($6.75 each).
23 Chewable Carbohydrates
An alternative to energy gels is the solid blocks of carbohydrate, such as Clif Bloks, or Gu Chomps. I don't generally recommend these alternatives for a number of reasons. The biggest problem is that it's harder to chew a block than to swallow a gel while running, especially if you're Breathing hard. A mistake can result in choking, which will really upset your running. The ingredients in the chewables are not as good as the gels – the primary ingredient in Clif Bloks is brown rice syrup and Gu Chomps use Tapioca Syrup. Sport Beans may be more convenient than the Clif Bloks or Gu Chomps but are nearly all sugar rather than the more easily digested Maltodextrin.