If you’ve browsed through race nutrition options, you’ve probably noticed that some gels are labeled “with caffeine.” But why is caffeine added—and should you be taking it?

Let’s break it down.

Why Gels Include Caffeine

Caffeine isn’t just a wake-up boost. It’s one of the most effective — if not, THE most effective — legal, and well-researched supplements in sports science, especially for endurance runners.

Here’s why:

1. It Lowers Perceived Exertion

Caffeine blocks adenosine receptors in your brain. Adenosine is a chemical that builds up as you get tired, making you feel sluggish. By blocking it, caffeine helps you feel less fatigued at a given pace so you can sustain effort longer without it feeling harder.

2. It Enhances Endurance

There are several studies show that caffeine can increase time to exhaustion and improve race performance. For example, a study found that caffeine increased time to exhaustion in runners by an average of about 17% (though individual responses varied widely—from just as few as 2% percent to over 30%).

3. It Sharpens Mental Focus

Caffeine stimulates your central nervous system, improving alertness, decision-making, and reaction time. This matters during technical courses, long-distance races, or when you’re deep into late-race fatigue.

4. It May Help With Fuel Efficiency

Some evidence suggests caffeine can enhance carbohydrate absorption in the gut and increase the rate at which muscles take in glucose—making your energy gels more effective

What Runners Should Watch Out For

Despite its benefits, caffeine isn’t for everyone. You’ll want to consider:

• Sensitivity: Some runners feel jittery, anxious, or nauseated.
• Overconsumption: Multiple gels can add up to over 400 mg of caffeine. That’s roughly 4–5 cups of coffee, which may lead to side effects.
• Sleep disruption: Caffeine’s half-life is 3–6 hours, so it can linger in your system post-race and can disrupt your sleep and impact recovery.
• Tolerance: If you take caffeine regularly, its race-day effect may be blunted as you may have already built a tolerance. Consider refraining or tapering caffeine taper beforehand.

Recommendations for Caffeine Use in Races

• Test in long run training first. As always, never try anything new on race day. The same goes for considering a caffeine strategy on race day.
• Use a mix of gels. Alternate between regular and caffeinated gels to stay in control of your total caffeine dose. For example, consider taking in a dose of caffeine at the start of a run as a boost and another dose towards the end to starve off fatigue.
• Time it smart. Caffeine peaks in 30–60 minutes. Use it when you need a lift, like in the second half of your race. Remember to space it out properly because by the time the caffeine hits, it may be too late.
• Start small. If you’re new to it, go with 25–50 mg per dose and work up from there.
• Cap it around 200–300 mg for a marathon, spaced out intelligently.

Bottom Line

Caffeine is a powerful — and legal — performance tool backed by decades of research. But like all tools, it works best strategically and with intention.

So if you’re considering caffeinated gels, know how it works, test it in training, and make it part of a larger fueling strategy — not just a shot in the dark.