When and how to take energy gels in cycling and running: complete guide
Knowing you need a gel is one thing. Knowing exactly when to take it — and how — is what separates athletes who finish strong from those who blow up in the final third of a ride or race.
This guide covers the timing, the technique and the most common mistakes. Everything you need to fuel intelligently on the bike or on foot.
When to start taking gels
The most common mistake in endurance nutrition is starting too late. By the time you feel your energy dropping, you're already behind — it takes 15–20 minutes for a gel to be absorbed and reach your muscles.
The rule: start fuelling before you feel you need to.
In cycling, take your first gel around the 40–50 minute mark or at kilometre 30–40, whichever comes first. In trail running and road running, from the 45–60 minute mark, depending on intensity. Before that, your glycogen stores are sufficient.
How often to take them
Once you've started, the general guideline is one gel every 30–45 minutes. The variation depends on intensity: the harder the effort, the more carbohydrates you burn per hour and the more frequently you need to refuel.
A practical guide by intensity:
- Zone 2–3 (endurance pace): one every 45–60 minutes.
- Zone 3–4 (tempo, sustained effort): one every 35–45 minutes.
- Zone 4–5 (race pace, high intensity): one every 25–35 minutes.
The critical moment: never take a gel at maximum effort
This is the most overlooked rule. At maximum intensity — a hard climb, a race surge, a sprint — blood flow to the digestive system is at its lowest. Taking a gel at that exact moment means it will sit in your gut unabsorbed, and can cause cramps or nausea.
The correct moment is just before or during a recovery section: a flat stretch after a climb, a technical descent, a brief drop in pace. That's when blood flow returns to the gut and absorption is efficient.
In cycling: take gels on flat or downhill sections, never mid-climb.
In trail running: take them at aid stations, on flat sections, or when you reduce your pace briefly.
Always take gels with water
A gel without water is a mistake. The concentrated sugars in a gel need water to dilute and be absorbed properly. Without it, the gel sits in your stomach as a hypertonic solution — which can actually draw water from your cells and worsen dehydration.
The minimum: 150–200ml of water with each gel. More is better. If you're in a section where drinking is difficult, wait until you can combine both.
Practical timing for cycling
Sportive or gran fondo: first gel at km 35–40. Then every 40–45 minutes. On climbs over 20 minutes, take the gel at the base — not mid-climb. Keep one in your back pocket for the final 20km.
Training ride over 2 hours: first gel at 50–60 minutes. Then every 45 minutes. On recovery rides, you may not need any — a banana or date works fine.
MTB and gravel: the variable terrain means you need to plan ahead. Identify your feed windows before the ride — descents, flat sections, technical stops. Take gels there, not on the steep stuff.
Practical timing for running
Marathon: first gel at km 10–12. Then every 7–8km or every 35–40 minutes. The critical zone is km 28–32 — always have a gel ready before you reach it.
Trail running: first gel at 45–60 minutes. Then every 35–45 minutes. At aid stations, take the gel and immediately follow it with water or isotonic drink.
Half marathon (under 1:45): one gel at km 8–10 is often enough. Focus more on pre-race nutrition.
Pre-race: the gel before the start
One gel 15–20 minutes before the start is one of the most effective strategies in endurance nutrition. It tops up your glycogen without overloading your stomach, and the carbohydrates are available exactly when the race begins.
This is where the dense texture of natural gels is especially useful — it absorbs gradually without creating a heavy feeling or pre-race nausea.
After 3 hours: listen to your gut
On very long efforts, the body's tolerance for sweet flavours tends to decline. Many athletes find that after 3–4 hours they simply don't want another sweet gel. This is normal — it's your gut telling you it needs variety.
In ultras and long sportives, alternate gels with salty foods, rice cakes, or broth. Gels remain the most efficient energy source, but digestive comfort matters more the longer the effort goes.
Natural gels without maltodextrin or artificial flavours hold up better in this regard — real fruit flavours are more tolerable at hour 5 than artificial ones.
The PICO advantage for timing
Each PICO gel contains 40–47g of carbohydrates in a 2:1 glucose-to-fructose ratio. The dense texture means it releases energy over a longer window than a liquid gel — which means you have a bit more flexibility on timing without the crash risk.
No maltodextrin means no aggressive glucose spike. No artificial additives means less digestive stress. The result: gels you can take consistently throughout a long effort without your stomach rebelling at hour 4.
