How Many Gels for a Marathon? (Simple Guide + Mile-by-Mile Timing)
Most marathon bonks happen because fueling starts too late. Here’s how many gels you need, when to take them, and how to build a simple plan you can actually execute on race day.
Quick Answer
Most marathoners need multiple gels — and they need to start earlier than they think. The simplest strategy is consistent small carb doses every ~20 minutes, adjusted by finish time and whether you’re also drinking carbs.
Mile 20 is where the marathon starts. It’s also where most marathoners fall apart.
And it usually isn’t because they didn’t train hard enough. It’s because they waited too long to fuel.
Quick Answer: How Many Gels for a Marathon?
| Feature | Typical gel count | Strategy | Best for |
|---|---|---|---|
| 3–5 gels | Conservative fueling | Often works for 3–4 hour runners who drink carbs too | Lower GI risk |
| 5–8 gels | Common “solid plan” range | Works well for many marathoners | Stable energy late |
| 8–10+ gels | Higher-carb approach (as tolerated) | Best when practiced in training and supported with fluids | Longer races / higher targets |
If you also take carbs from sports drink, you can often reduce gel count. The real target is carbs per hour — gels are just one way to hit it.
The Rule That Stops Most Marathon Bonks
Start fueling before you need it. If you wait for hunger or fatigue, you’ll almost always start too late.
- Start early (often within the first 20–30 minutes).
- Repeat on a simple interval (often ~20 minutes).
- Keep doses smaller and consistent instead of “big hits.”
Simple Timing Schedules (You Can Memorize These)
| Feature | Race duration | Example gel timing (minutes) | Notes |
|---|---|---|---|
| ~3 hours | 20, 40, 60, 80, 100, 120, 140 | Often 6–7 gels (or fewer with carb drink) | Keep it steady |
| ~4 hours | 20, 45, 70, 95, 120, 145, 170, 195, 220 | Often 8–9 gels | Smaller doses reduce GI risk |
Hydration + Sodium: The Multiplier
Gels don’t work well if you’re dehydrated. They also don’t work well if you’re washing them down with only water for hours (especially if you’re a salty sweater).
The simple goal: consistent fluids and some sodium, especially as duration and heat rise. MAVR uses your sweat profile (if you have it) to make this less guessy.
Frequently Asked Questions (FAQ)
Is it possible to take too many gels?
Yes — especially if you haven’t practiced. Too much too fast causes nausea and bloating. Build tolerance gradually in training and aim for smaller, consistent doses.
Should I take a gel at mile 20?
If mile 20 is your first “serious” fuel, you’re already behind. Most plans work better starting early and repeating consistently.
Do I need gels if the course has sports drink?
Maybe fewer. If the sports drink provides carbs you tolerate, it can replace part of your gel intake. Practice with what you’ll use on race day.
How do I practice my marathon fueling plan?
Use long runs as rehearsals: same timing, same products, same amounts. Your gut adapts with consistent practice.