Energy gels have become the default fuelling choice for cyclists. They're compact, portable, and deliver carbohydrates quickly. The number of brands and formulations has exploded over the past few years — which means there's a lot of marketing noise to cut through.
Let me break down what actually matters when choosing and using gels, because the difference between getting this right and getting it wrong is the difference between finishing strong and finishing in a bush.
How Energy Gels Work
A gel is essentially a concentrated carbohydrate delivery system. Most contain 20-30g of carbohydrates in a single-serve sachet, designed to be absorbed quickly and converted into energy your muscles can use.
The carbohydrates enter your bloodstream through your small intestine. The speed of absorption depends on the type of carbohydrate:
Glucose (or maltodextrin): Absorbed through the SGLT1 transporter in your gut lining. Maximum absorption rate: approximately 60g per hour through this pathway alone.
Fructose: Absorbed through a different transporter (GLUT5). Maximum rate: approximately 30-40g per hour.
This is why the best gels use a combination of both. By engaging two separate absorption pathways, you can take in up to 90-120g of carbohydrate per hour — dramatically more than glucose alone.
What to Look for on the Label
Carbohydrate Type and Ratio
The gold standard is a 2:1 or 1:0.8 glucose-to-fructose ratio. This ratio maximises carbohydrate absorption and minimises gut distress. Most premium gels now use this formulation — check the ingredients.
If the label just says "maltodextrin" with no fructose source, you're limited to 60g per hour maximum absorption. Fine for shorter efforts, but a limitation on longer rides where you need 80-120g per hour.
Carb Content Per Gel
Gels typically contain between 20-45g of carbohydrates. Higher-carb gels mean fewer sachets to carry and fewer packets to open — a real advantage when you're trying to fuel at race pace.
A 25g-carb gel requires 4 gels per hour to hit 100g/hr. A 40g-carb gel only needs 2-3. Fewer gels means less packaging, less opening and squeezing, and less chance of forgetting.
Electrolytes
Some gels include sodium (200-300mg per gel). This is useful on hot days or long events when sweat losses are significant. If your gel doesn't contain electrolytes, supplement with electrolyte tablets in your bottles.
Caffeine
Many brands offer caffeinated versions (30-75mg per gel). Caffeine is a proven performance enhancer, but time it strategically — save caffeinated gels for the second half of a race or the final push. Using caffeine too early wastes its ergogenic effect.
A sensible race strategy: regular gels for the first two-thirds, caffeinated gels for the final third.
When to Take Gels
Timing matters more than most people realise. The goal is to maintain a steady supply of carbohydrate to your working muscles — not to wait until you're bonking and then frantically eat three gels in five minutes.
Start early. Take your first gel 20-30 minutes into the ride, well before you feel any fatigue. By the time you feel hungry, you're already behind.
Be consistent. Set a recurring timer on your bike computer. Every 20-30 minutes, take a gel or equivalent. This creates a steady drip of carbohydrate rather than boom-and-bust spikes.
Don't wait until it's too late. Once you've bonked, gels can help you limp home, but they won't restore full performance. The glycogen deficit is too large to fix on the fly. Prevention through consistent fuelling is the only strategy.
How to Take a Gel Without Crashing
Taking a gel while riding at speed is a skill. Here's the technique:
- Move the gel to an easily accessible pocket before you need it — jersey centre pocket or top tube bag
- Choose a smooth section of road with no technical demands
- Open the gel with your teeth (or pre-open gels before the ride by tearing the top and folding it over)
- Squeeze the gel into your mouth
- Follow immediately with a few mouthfuls of water
That last point is important. Gels are concentrated. Taking them without water can cause stomach cramping as your body pulls fluid into the gut to dilute the concentrated carbohydrate. Always chase a gel with water.
Some newer gel formulations are designed to be taken without water — they're more dilute, more like a thin syrup than a thick paste. These are genuinely easier on the stomach but deliver fewer carbs per sachet.
Training Your Gut
Your gut is a trainable organ, and this is one of the most important things I can tell you. If you currently can't tolerate more than one gel per hour without stomach issues, that's not your permanent limit — it's your current training level.
Start with one gel every 30 minutes during training rides. After two weeks, increase to one every 25 minutes. Gradually work up to your target race intake over 6-8 weeks.
The gut adapts by upregulating the transporters that absorb carbohydrates. Cyclists who regularly practise high-carb fuelling in training can absorb significantly more than those who don't. This is why the pros can smash 120g per hour without issues — they've trained their guts for years.
For more detail on gut training protocols and in-ride nutrition strategies, check our complete in-ride nutrition guide.
Gel Alternatives: When Gels Aren't Right
Gels aren't the only option. Some riders prefer:
Energy chews: Similar nutrition to gels in a chewable format. Easier to eat in small portions. The downside is they require more chewing, which can be difficult at high intensity.
Rice cakes and bars: Real food alternatives for longer, lower-intensity rides. More satisfying, less gut stress for some riders. Harder to eat at race pace.
Liquid nutrition: Energy drink powder in your bottles. The easiest way to fuel because you're already drinking. The limitation is that you can only carry so much fluid, and in hot conditions your bottle space is needed for hydration.
The best approach for most cyclists: gels as the primary fuel source, supplemented with energy drink in the bottles and solid food for ultra-distance events.
Common Gel Mistakes
Testing new gels on race day. Never. Always. Test in training first. What works for your mate might wreck your stomach.
Taking gels without water. Concentrated carbohydrate plus zero fluid equals stomach cramps. Always have water available.
All glucose, no fructose. If you need more than 60g per hour — and you do for any effort over 90 minutes — you need a dual-source formulation.
Too much caffeine. Stacking multiple caffeinated gels plus coffee plus pre-workout is a recipe for jitters, elevated heart rate, and GI distress. Limit total caffeine to 3-6mg per kg body weight across the entire event.
Key Takeaways
- Choose gels with a 2:1 or 1:0.8 glucose-to-fructose ratio for maximum absorption
- Higher-carb gels (40g+) mean fewer sachets and fewer interruptions during a ride
- Start fuelling at 20-30 minutes into the ride, then every 20-30 minutes consistently
- Always take gels with water to avoid stomach cramping
- Save caffeinated gels for the second half of the event
- Train your gut progressively over 6-8 weeks to handle race-level intake
- Test every product in training before using it on race day
- Check our In-Ride Nutrition Guide for the complete fuelling strategy
- Use the In-Ride Fuelling Calculator to find your personalised carb targets
- For race day, see our race day nutrition guide for the full timeline
- Hydration is essential alongside gels — always chase with water
