The Mile 20 Caffeine Mistake That’s Costing You Minutes—And How Pros Avoid It
Estimated read time: 3.36 minutes (about as long into your marathon as it takes to realize you need to find a bathroom. 🚽😅)
Hey Performance Nerds! Jonah here. 🤓
Most runners make the same mistake: they take their caffeine gel at mile 20.
By the time it peaks (45–60 minutes later), you’re already across the finish line. That’s a wasted performance boost.
Here's what you'll learn today:
✅ When to take caffeine so it peaks when you actually need it
⚖️ The exact dose based on your body weight (not guesswork)
🏃♂️ Why pros take their caffeinated gel around mile 8-10, not mile 20
This one started as a quick Instagram Reel that did surprisingly well, so here’s the deeper dive for the newsletter crew.
(Augie’s never needed caffeine. He already runs on pure mailman-induced adrenaline.)
🎁 Big Update: New Referral Rewards Are Live!
We just upgraded the Marathon Science referral program — and the new prizes are 🔥
👟 Refer 1 friend → Get The Ultimate Shoe Rotation Guide (29 pages)
Your complete blueprint to smarter shoes: weekly rotation schedules, 50+ reviews, and science-backed guidance on how to match cushioning, drop, and carbon plates to every run.
📞 Refer 50 friends → Get a 1:1 Coaching Call with Me
A private 30-minute strategy session to dial in your training, fueling, or recovery — usually reserved for NFL athletes.
Ready to claim yours? Share your link below and start earning rewards. 👇
🧬 Performance Sponsors:
🚀 Train Harder. Recover Smarter.
SiS—the same science-backed fuel trusted by Olympic marathoners—is now sponsoring Marathon Science.
From gels to recovery tools, every product is backed by real performance data and built for serious athletes like you.
🚀 Power Your Pace with Stryd
Stryd — the running power meter trusted by serious athletes — is now an official performance sponsor of Marathon Science, delivering real-time pacing precision so you can train smarter and race faster.
💡 See this week’s full Stryd training tip at the end of this newsletter.
🧠 The Science — How Caffeine Actually Works
Caffeine doesn’t give you new energy. It changes how your brain interprets fatigue.
As you run, a molecule called adenosine builds up and triggers fatigue signals in your brain. Caffeine blocks those receptors.
Think of it like turning down the "pain volume" knob in your head. You can hold pace longer because your brain isn't screaming at you to slow down.
The timeline looks like this:
15 minutes: Caffeine enters your bloodstream.
45–60 minutes: Peak blood levels (maximum effect).
1–2 hours: Prime performance window.
3–5 hours: Half-life (still active but fading).
Research shows caffeine improves endurance by 2–4% on average. For a 3-hour marathoner, that's 4–7 minutes.
But only if you time it right.
Taking 200mg more caffeine won't help if your timing is wrong. You need it working before fatigue sets in, not after.
⏱️ The Protocol — When & How to Take It
Your caffeine strategy should match your race distance:
Race Duration | Pre-Race Dose | In-Race Top-Ups | Notes |
|---|---|---|---|
<2 hours (Half Marathon) | 3–6 mg/kg | None needed | One pre-race dose is enough |
2–3 hours (Marathon) | 3–6 mg/kg | 1–2 gels early (30–90 min in) | Peaks in final third |
>3 hours (Ultra) | 3–6 mg/kg split doses | 100-200 mg every 60–90 min | Maintain steady levels |
The three-step approach:
Pre-race: Take 3–6 mg/kg of caffeine 45–60 minutes before the gun. Coffee, gel, or capsule.
In-race: Add 100-200 mg every 45–60 minutes. Take these in the first half so they peak when you need them.
Total ceiling: Don't exceed ~6 mg/kg combined (pre-race + in-race). More = side effects without benefit.
I personally cap at 200–400 mg total for a marathon. Find your ceiling in training.
Each gel has 75–200 mg. Check labels and do the math.
🚨 The Mile 20 Trap (Why "Save It for the End" Fails)
That late gel? It peaks after you finish. You'll feel it working while you're grabbing your medal.
Caffeine must peak before fatigue. It takes 45–60 minutes to hit, so work backwards.
For a marathon, your key effort window is miles 18–26. Take your caffeine around mile 8–10, about 60–75 minutes into the race.
This is why elite runners take their caffeine early. They know the science.
If a late gel still gives you a boost, take it. Just make sure you're also fueling early when the timing actually works.
MY SiS BETA FUEL + Nootropic Gel Strategy (3-Hour Marathon)
⚖️ Individual Differences — Find Your Sweet Spot
Not everyone responds to caffeine the same way. You won't know your sweet spot until you test.
Don’t quit coffee before race week. Daily drinkers still get the same performance boost—no detox needed.
Watch for side effects like GI distress, jitters, or a racing heart rate if you’re using untested doses.
Practice your caffeine plan like any other gear test:
Try 1–2 mg/kg on a long run
Track heart rate, gut feel, and effort
Adjust over time until it feels dialed
You wouldn't test new shoes on race day. Don't test a new caffeine strategy either.
🎯 Key Takeaways
✅ Timing beats dosage: Take caffeine 45–60 minutes before the start and within the first third or half of your race
✅ 3–6 mg/kg total = proven sweet spot
✅ Add 100–200 mg every 45–60 minutes to stay topped up—but keep total race-day caffeine under 400 mg
✅ Test in training before race day
⚠️ Avoid the mile 20 trap—that gel will peak after the finish line
💬 One last thing before you go.
After the NFL, I wasn't sure if obsessing over performance science still mattered—until this community proved it does.
Your training goals? They brought that fire back.
If you're testing caffeine strategies or still figuring out your fueling plan—hit reply and tell me how it's going. I read every message and I'm here to help.
Are You a True Running Nerd? Prove it.. 🧐
Welcome to the prove you’re a nerd section. Each week, I ask a question about a common running science myth.
Answer correctly, and you’ll be entered into a weekly raffle to win a package of Jonah’s favorite supplements.
Why do endurance athletes mix fructose with glucose when fueling above ~60 g of carbs per hour?
- A. Fructose provides a slower, steadier release of energy than glucose 🕒🍯
- B. Fructose uses a different intestinal transporter (GLUT5), allowing more total carbs to be absorbed per hour 🚀🧬
- C. Fructose spares muscle glycogen by forcing fat oxidation 🥑🔥
- D. Fructose boosts insulin response to improve muscle uptake of glucose 💉⚡
Last Week’s Results: The Calf Tax 💥🦶
Minimalist fans, brace yourselves, this one hit right in the soleus (lol). Most of you got it right: low-drop shoes look sleek, but they make your calves do double duty every stride.
The correct answer?
C. Low drop (0–4 mm) 🦶🔥 ✅
A lower heel-to-toe drop shifts more of the load from your quads to your calves. That extra dorsiflexion increases Achilles tension and calf workload—great for strength over time, but risky if you ramp up mileage or transition too fast.
Here’s how the votes shook out:
🟨 A. High drop (10–12 mm) 👟⬆️ – 77
⬜️ B. Moderate drop (6–8 mm) ⚖️ – 7
🟩 C. Low drop (0–4 mm) 🦶🔥 – 192 ✅
⬜️ D. It doesn’t matter—calf load is the same in all 🏃♂️🤷 – 23
Bottom line?
Low-drop shoes build strong calves, but only if you earn the right to wear them. Transition slowly, or you’ll pay the calf tax early. 💸🦵
🏃♂️ Stryd Training Tip — Treadmill vs Outdoor: Does It Really Matter?
Short answer: not much.
Bas van Hooren’s research shows treadmill and outdoor running are nearly identical for stride mechanics and muscle activation. So your data—and your gains—translate almost perfectly between the two.
Still, a few small differences show up:
Less air resistance indoors → slightly easier effort at the same pace
Softer surface → marginally less impact load
Longer contact time → tiny drop in leg stiffness
That’s it. Nothing that ruins your training or makes your treadmill runs “fake miles.”
How to use Stryd:
Treat treadmill runs as normal sessions—your power data stays accurate.
Expect pace to read a bit faster at the same power.
When switching outside, give one easy run to recalibrate.
💡 Bottom line: Treadmill or tarmac, your stride—and your Stryd—tell the same story.
Don’t forget: You + Science = AWESOMENESS 😎
Yours in science,
Jonah
P.S. - We have a crew of 20,341+ nerds here who are running FAST using science.
Did you need running science advice or tips? 🏃♀️💨🧪
Reply with your question, Augie and I (pictured below) will get back to you with science-backed tips!
Enjoy the newsletter? Please forward to a pal. It only takes 18 seconds. Making this one took 11.23 hours.
Please email me directly if you’re interested in references for this week!