There is no single winner. Maurten Gel 100 suits runners who want a neutral taste and a gentle gut feel. GU Energy Gel suits runners who want flavor variety and a caffeine option. SiS GO Isotonic suits runners who want a thinner gel they can take without water. The right one is the gel your stomach handles at goal pace after three or four long-run rehearsals.
Below we compare the three on what matters over 42.2 km: carbohydrates, caffeine, texture, water needs, how many you carry and how to test them before race day in Singapore’s heat and humidity.
TL;DR
- Maurten Gel 100: 25g carbs per 40g serving, caffeine-free, hydrogel texture, mild taste. Best for sensitive stomachs.
- GU Energy Gel: 22g carbs per 32g serving, 20mg or 40mg caffeine depending on flavor, many flavors. Best for taste variety and a caffeine boost. Take it with water.
- SiS GO Isotonic: 22g carbs, thinner isotonic format, no water needed. Best if you dislike thick gels or struggle to drink at pace.
- Plan 60g of carbs an hour as a starting point, then adjust in training. Never debut a gel on race day.
- You can shop all three at Racepack SG with next-day delivery within Singapore.
Table of Contents
- Maurten vs GU vs SiS at a glance
- Maurten Gel 100: the gentle option
- GU Energy Gel: flavor and a caffeine choice
- SiS GO Isotonic: the no-water option
- Carbs, caffeine and water: what the numbers mean
- How many gels do you need for a marathon?
- How to choose: a quick decision guide
- Test your gel before race day
- Our perspective
- Stock up for your marathon
- Practical tips for race week
- FAQ
- Ready to fuel your race?
- Sources
Maurten vs GU vs SiS at a glance
Here is the side-by-side before we go into detail. Figures are per standard gel and come from the sources linked in each section. Recipes and flavors change, so always read the label on the pack you buy.
| Feature | Maurten Gel 100 | GU Energy Gel | SiS GO Isotonic |
|---|---|---|---|
| Carbs per gel | 25g (40g gel) | 22g (32g gel) | 22g |
| Caffeine | None in the standard gel | 20mg or 40mg, depending on flavor | Standard gel is non-caffeinated |
| Texture | Thick hydrogel | Concentrated, sticky | Thinner, isotonic |
| Water with it | Helpful | Required | Not needed |
| Taste | Close to neutral | Strong, recognizable flavors | Varied flavors, lighter feel |
| Best for | Sensitive stomachs | Flavor lovers, caffeine users | Runners who skip water at aid stations |
Sources for the figures: Fit&Well’s running gel roundup for Maurten and GU, and our own SiS GO Isotonic product page for SiS.
Maurten Gel 100: the gentle option
Maurten Gel 100 delivers 25g of carbohydrate in a 40g serving and is caffeine-free, according to Fit&Well. That makes it the most carb-dense of the three per gel, so you need fewer of them to reach the same hourly target.
The selling point is the hydrogel. Maurten describes a format that forms a gel in the stomach, and Fit&Well reports it is designed to be absorbed through the small intestine to lower the risk of an upset stomach compared with standard formulas. RunDataLab notes the claims around faster gastric emptying and less GI distress, and adds that independent research is still limited but growing.
The ingredient list is short: glucose, fructose, calcium carbonate, gluconic acid and sodium alginate, plus water, as Runivore lists it. The glucose and fructose mix matters because two carbohydrate types use separate absorption routes. Our guide to energy gel ingredients that speed carb uptake explains why.
Who it suits: runners with a history of stomach trouble, runners who find sweet gels hard to face after 30km, and anyone who wants a plain taste. Expect a thick texture, which some runners notice at first.
You can pick up Maurten Gel 100 in our store.
GU Energy Gel: flavor and a caffeine choice
GU Energy Gel gives 22g of carbs in a 32g serving, with 20mg or 40mg of caffeine depending on the flavor, per Fit&Well. The same review calls it concentrated and sticky, with water required, and says it may not suit very sensitive stomachs.
The upside is variety. Long races are as much a mental job as a physical one, and a flavor you look forward to at 30km can help you keep taking in fuel. A personal account from Running Momma describes GU’s taste as recognizable and its texture as thick, and some runners find it cloying after several gels. That is one runner’s view, but it shows why taste tolerance deserves a place in your decision.
Caffeine flavors let you plan a late-race lift. A common approach is to keep early gels caffeine-free and use caffeinated ones later, but test it, because caffeine affects people differently. If you are sensitive to caffeine, or run an early morning race and want to sleep well the night before, stick with the non-caffeinated options.
We stock caffeinated flavors such as GU Salted Caramel and GU Salted Watermelon, both in 6, 12 or 24 packs, plus the GU Roctane assorted pack built for longer efforts.
Who it suits: runners who like a bold flavor, want caffeine in the second half, and are comfortable carrying water or running between aid stations.
SiS GO Isotonic: the no-water option
SiS GO Isotonic provides 22g of carbs per sachet and is designed to be taken without extra water, as shown on our SiS GO Isotonic gel page. The format is larger and thinner than a concentrated gel, which is why water is not part of the routine.
That suits runners who struggle to grab cups at crowded aid stations, or who get a sloshing stomach when they combine gel and water. RunDataLab points out that GO Isotonic uses maltodextrin only, with no fructose, and that single-source carbohydrate is generally tied to an absorption ceiling of roughly 60g per hour. For many recreational marathoners, 60g an hour is already a solid target, so this is rarely a problem. Runners who want to push toward 90g an hour usually look at mixed-carbohydrate products.
You can buy it as a single gel in your choice of flavor to trial, or as a 30 pack once you know it works for you.
If you want a caffeine option from the same brand, SiS BETA Fuel + Nootropics is a caffeinated gel in our range.
Who it suits: runners who dislike thick gels, runners who skip water at some aid stations, and anyone starting out with gels who wants a gentle first step.
Carbs, caffeine and water: what the numbers mean
On paper, the three are close. Maurten gives 25g per gel, GU and SiS give 22g. A comparison from StripeFit shows the same pattern. The difference of 3g per gel is small. What changes your race is how you take them.
- Carbohydrate: Maurten gets you there in fewer gels. GU and SiS need slightly more.
- Caffeine: only GU’s flavor range builds caffeine into several standard gels. Maurten and SiS offer caffeinated versions as separate products.
- Water: GU needs water. Maurten is easier with some. SiS GO Isotonic is built to be taken without.
Treat water and caffeine as separate decisions from carb quantity. Many runners get the carbs right and then struggle because the gel they chose forces a drinking routine they cannot manage at pace.
How many gels do you need for a marathon?
A common starting target is 60g of carbs per hour. RunDida’s marathon fueling guide gives 30g per hour as a minimum and 90g with mixed carbohydrate sources as an upper range, and suggests starting the first gel around 30 to 45 minutes in.
Translated into gels, using the figures above and RunDataLab’s arithmetic:
| Finish time | Gel at 60g/hour (approx.) | Maurten (25g) | GU or SiS (22g) |
|---|---|---|---|
| 3:30 | about 210g total | 8 to 9 gels | 9 to 10 gels |
| 4:00 | about 240g total | 9 to 10 gels | 11 gels |
| 4:30 | about 270g total | 10 to 11 gels | 12 gels |
These are our own calculations from the per-gel carbohydrate figures, assuming steady intake from the start, not a prescription. You may also take carbs from sports drink at aid stations, which lowers your gel count. Our guide on how many energy gels you need for a full marathon goes deeper on planning.
How to choose: a quick decision guide
- Stomach often upsets you in long runs? Start with Maurten Gel 100.
- You skip water or struggle with thick textures? Try SiS GO Isotonic.
- You want strong flavors and a caffeine lift late in the race? Try GU caffeinated flavors.
- You get bored of sweetness? Mix: a neutral gel early, a flavored one later. Just rehearse the combination.
- You need to carry many gels? Higher carbs per gel (Maurten) means a lighter load for the same fuel.
Budget matters too. Marathon training uses a lot of gels, so a sensible plan is to buy a pack of your race gel for the long runs and keep the rest of your training fueling simpler. Check current pack prices on each product page.
Test your gel before race day
Every source we reviewed agrees on one point: practice decides what works. Long runs are fueling rehearsals, and the gut adapts to the carbohydrate you train it with.
A simple rehearsal plan:
- Weeks 12 to 8 out: use your chosen gel on long runs, one every 30 to 45 minutes.
- Weeks 8 to 4 out: raise toward your race-day hourly target and practice taking the gel with or without water as you will on the day.
- Final 3 long runs: use the exact flavor, timing and caffeine plan you will race with, at goal pace in the heat you expect.
- Race morning: eat what you rehearsed. Bring more gels than you think you need, since sweaty hands and dropped gels happen.
If a gel causes stomach cramps, nausea or bloating repeatedly in training, switch format. If symptoms persist or are severe, speak to a doctor or a sports dietitian.
Our perspective
We hear the same question from runners across Singapore: which gel is best? Our answer is that the best gel is the one you can take on schedule for four hours without thinking about it.
That is why we carry all three brands instead of asking you to pick a side. Maurten Gel 100 is what we suggest first for runners who worry about their stomach. SiS GO Isotonic is a practical choice when drinking at pace is hard. GU gives you flavor and caffeine choices that keep fueling interesting in the second half.
Buy a few, rehearse them on your long runs, and lock in your plan well before race week. We built Racepack around that approach: authentic products, next-day delivery within Singapore, and enough choice to find your fit.
Jason John
Stock up for your marathon
We are an official retailer for major brands, and we guarantee product authenticity. That matters when you are spending months training for one race and need to trust what is in the pack. Order Maurten, GU and SiS together for your build-up, with next-day delivery within Singapore.
Start with Maurten Gel 100 if you want a gentle option, or browse all energy gels and hydration to build your race-day kit. If you also want something for after the finish line, see our recovery powders and protein powders.
Practical tips for race week
- Lay out your gels by kilometer or time, and tape or pin them to your race belt in order.
- Practice opening each gel with sweaty hands.
- Keep your caffeine plan simple: one caffeinated gel late is easier to judge than several.
- Pair gels with electrolytes if you sweat heavily. Our SiS GO Electrolyte Powder and SiS GO Energy Powder are options for drink-based fueling.
- Do not try a new flavor in the last week.
FAQ
Which is the best energy gel for a marathon: Maurten, GU or SiS?
None wins for everyone. Maurten Gel 100 is a strong first choice for sensitive stomachs, GU suits runners who want flavor and caffeine options, and SiS GO Isotonic suits runners who prefer no water. Choose by testing in long runs.
How many carbs are in each gel?
Maurten Gel 100 has 25g per 40g serving, and GU Energy Gel has 22g per 32g serving, according to Fit&Well. SiS GO Isotonic has 22g per sachet. Always check the pack, since recipes can change.
Do I need water with these gels?
GU Energy Gel is concentrated and needs water. Maurten is usually easier with some water. SiS GO Isotonic is designed to be used without extra water.
Which gel is best for a sensitive stomach?
Many runners start with Maurten Gel 100 because of its hydrogel format, which is designed to be gentle on the stomach. Independent research is still growing, so rehearse it in training and see how you respond.
Which gels have caffeine?
Maurten Gel 100 and SiS GO Isotonic in their standard versions are non-caffeinated. GU has 20mg or 40mg in certain flavors, and we also stock caffeinated options such as SiS BETA Fuel + Nootropics. Check each product page for the amount.
How many gels should I take per hour?
Many marathoners aim for about 60g of carbs an hour, which is roughly 2 to 3 gels depending on the gel. Start with fewer, build up in training, and adjust for your gut tolerance.
When should I take my first gel?
A typical plan is to take the first gel 30 to 45 minutes into the race, then continue at regular intervals. Do not wait until you feel tired.
Can I mix different gel brands in one race?
Yes, if you have rehearsed the mix. Some runners use a neutral gel early and a flavored caffeinated one late. Never combine products for the first time on race day.
Do you deliver energy gels in Singapore?
Yes. Racepack SG offers next-day delivery within Singapore on in-stock products, and guarantees product authenticity.
What else should I buy for marathon fueling?
Many runners add electrolytes or an energy drink mix, and a recovery or protein powder for after the run. Browse our hydration, recovery and protein collections.
Ready to fuel your race?
Pick your gel, test it, and show up on race day with a plan. Buy Now at Racepack SG and get next-day delivery within Singapore.
Sources
- Best running gels, Fit&Well
- SiS vs. Maurten vs. Huma energy gels, Runivore
- Running gels compared, Running Momma
- Maurten vs GU vs SiS Energy Gels, StripeFit
- Marathon Nutrition: Science-Based Fueling Guide, RunDida
