Mavr Sports Nutrition Team
October 2, 2026. 10 min read.
Caffeine is the most common legal performance aid in Hyrox, and for good reason. It makes hard work feel a little easier, and Hyrox is about an hour or more of hard work. But a lot of athletes get the details wrong. They take a big pre-workout scoop on top of two coffees, start shaking in the start pen, then lie awake until 2 am after a late wave.
This guide covers how much caffeine to take for your body weight, when to take each form (coffee, capsule, gum, or gel), whether you need any during the race, and how to plan around sleep when your wave is in the afternoon. All doses here stay inside published safety limits for healthy adults. Try every part of this in training before race day.
Yes, for most people. The International Society of Sports Nutrition (ISSN) reviewed the research and found that caffeine improves a wide range of performance, from endurance to muscular endurance, sprinting, jumping, and strength. A separate meta-analysis found small but real gains in maximal strength and power. Hyrox needs both: 8 km of running and eight stations, from the SkiErg to 100 wall balls. Caffeine will not replace training or a good breakfast, but it can make a hard race feel slightly easier.
Research on performance uses doses of 3 to 6 mg per kg of body weight, and the ISSN notes the lowest dose that works may be as low as 2 mg per kg. Higher doses bring more side effects: a racing heart, shaking, an upset stomach, and poor sleep. Very high doses, around 9 mg per kg, cause side effects in many people and are not needed for a benefit.
For safety, the European Food Safety Authority (EFSA) found that single doses up to 200 mg (about 3 mg per kg for a 70 kg adult) raise no safety concern for healthy adults, even when taken less than 2 hours before hard exercise. It also found up to 400 mg spread across a day is fine for healthy adults who are not pregnant. So for a race of about an hour, we suggest 2 to 3 mg per kg, with the pre-race dose capped at 200 mg.
| Body weight | Low dose (2 mg/kg) | Standard dose (3 mg/kg, max 200 mg) |
|---|---|---|
| 55 kg (121 lb) | 110 mg | 165 mg |
| 65 kg (143 lb) | 130 mg | 195 mg |
| 75 kg (165 lb) | 150 mg | 200 mg |
| 85 kg (187 lb) | 170 mg | 200 mg |
| 95 kg (209 lb) | 190 mg | 200 mg |
Caffeine starts to act about 15 to 30 minutes after you swallow it, and the most common timing in research is 60 minutes before exercise. Gum is different. It is absorbed through the lining of your mouth, so it gets into your blood faster, and the ISSN notes it may need a shorter wait.
Coffee
When to take it45 to 60 minutes before your wave
Good to knowDose varies a lot. A 250 ml mug of brewed coffee has about 100 mg on average
Capsule or tablet
When to take it45 to 60 minutes before
Good to knowExact dose, no extra liquid in your stomach
Caffeine gum
When to take it10 to 15 minutes before, in the start area
Good to knowActs faster. Handy when start times slip. Check the dose on the pack
Caffeinated gel
When to take it15 to 30 minutes before the start
Good to knowGives carbs and caffeine together. Check the label and count it in your total
Energy drink
When to take it45 to 60 minutes before
Good to knowCarbonation and volume can upset your stomach. A typical 250 ml can has about 80 mg
Pre-workout powder
When to take itOnly if you know the exact dose
Good to knowMany contain 200 mg or more plus other stimulants. Easy to overdo
| Form | When to take it | Good to know |
|---|---|---|
| Coffee | 45 to 60 minutes before your wave | Dose varies a lot. A 250 ml mug of brewed coffee has about 100 mg on average |
| Capsule or tablet | 45 to 60 minutes before | Exact dose, no extra liquid in your stomach |
| Caffeine gum | 10 to 15 minutes before, in the start area | Acts faster. Handy when start times slip. Check the dose on the pack |
| Caffeinated gel | 15 to 30 minutes before the start | Gives carbs and caffeine together. Check the label and count it in your total |
| Energy drink | 45 to 60 minutes before | Carbonation and volume can upset your stomach. A typical 250 ml can has about 80 mg |
| Pre-workout powder | Only if you know the exact dose | Many contain 200 mg or more plus other stimulants. Easy to overdo |
A simple plan that works for many people: a normal mug of coffee with breakfast 2 to 3 hours before, then caffeine gum or a capsule closer to the start to reach your target dose. Remember the coffee from breakfast still counts.
Usually not. In healthy adults, it takes about 4 hours on average for the body to clear half of a caffeine dose. A dose taken 45 to 60 minutes before your wave is still working when you reach the wall balls in a 60 to 90 minute race. If you expect to race longer than about 90 minutes and plan to take a gel anyway, a caffeinated gel on the run out of station 4 or 5 can give a late lift. Count it in your total, and keep the pre-race dose lower to make room.
Hyrox waves run all day, and many athletes start in the afternoon. Caffeine and sleep do not mix well. A meta-analysis of 24 studies found caffeine cut total sleep by about 45 minutes on average. To avoid losing sleep, it suggested a mug of coffee (about 107 mg) at least 8.8 hours before bed, and a typical pre-workout serve (about 218 mg) at least 13.2 hours before bed. Another study found 400 mg taken 6 hours before bed still disturbed sleep.
Before about 10:30
Up to 3 mg per kg, max 200 mg
About 10:30 to 14:30
About 100 to 150 mg. The higher end may cost some sleep
After about 14:30
About 100 mg or less, or none. Accept a shorter night only if this is your one race
Racing again the next day
Go lower on day one. Sleep matters more than a few seconds
| Your wave (bedtime about 22:30) | Suggested pre-race caffeine |
|---|---|
| Before about 10:30 | Up to 3 mg per kg, max 200 mg |
| About 10:30 to 14:30 | About 100 to 150 mg. The higher end may cost some sleep |
| After about 14:30 | About 100 mg or less, or none. Accept a shorter night only if this is your one race |
| Racing again the next day | Go lower on day one. Sleep matters more than a few seconds |
One short night before a rest day is not a disaster. But if you race singles on Saturday and doubles on Sunday, or have a hard week of training ahead, a smaller dose on a late wave is the better trade. Do not use extra caffeine in the evening to stay alert at the venue. Eat instead.
No. The ISSN found no consistent difference in the performance effect of caffeine between people who use it every day and people who do not. Keep your normal coffee habit in race week, so you avoid withdrawal headaches. On race day, just make sure your usual coffee plus your race dose stays under 400 mg.
Never try caffeine, or a new form of it, for the first time on race day. Pick a simulation or a hard compromised run session at the same time of day as your wave. Use the exact product and dose you plan to race with. Afterward, write down how you felt at the start, whether your stomach was fine, whether your heart rate felt odd, and how you slept that night. Do this at least twice. If it went badly, drop to 2 mg per kg or try a different form.
Breakfast
Morning wave at 09:0006:30, with one mug of coffee (about 100 mg)
Afternoon wave at 15:30Normal breakfast with your usual coffee before 08:00
Pre-race meal
Morning wave at 09:00Part of breakfast
Afternoon wave at 15:30Carb lunch around 12:30, no coffee
Race dose
Morning wave at 09:0008:45: caffeine gum (about 100 mg)
Afternoon wave at 15:3015:15: gum or half a capsule (about 70 to 100 mg), or none
Day total
Morning wave at 09:00About 200 mg
Afternoon wave at 15:30About 170 to 200 mg, most of it before 08:00
| 70 kg athlete | Morning wave at 09:00 | Afternoon wave at 15:30 |
|---|---|---|
| Breakfast | 06:30, with one mug of coffee (about 100 mg) | Normal breakfast with your usual coffee before 08:00 |
| Pre-race meal | Part of breakfast | Carb lunch around 12:30, no coffee |
| Race dose | 08:45: caffeine gum (about 100 mg) | 15:15: gum or half a capsule (about 70 to 100 mg), or none |
| Day total | About 200 mg | About 170 to 200 mg, most of it before 08:00 |
Want the numbers sized to you? Our free Hyrox nutrition calculator sets your pre-start caffeine at 3 mg per kg (capped at 200 mg), counts caffeinated gels toward a 400 mg race limit, and lowers the dose for relay legs.
About 2 to 3 mg per kg of body weight, with the pre-race dose capped at 200 mg. For a 70 kg athlete that is about 140 to 200 mg. Start at the low end and only use the higher dose if you have tried it in a hard session.
Coffee, capsules, and energy drinks about 45 to 60 minutes before your wave. Caffeine gum about 10 to 15 minutes before, because it is absorbed through the mouth and acts faster. A caffeinated gel 15 to 30 minutes before the start.
Not better, just faster. Gum lets you take caffeine close to the start without a full stomach, which helps when start times slip. Coffee is fine if you drink it 45 to 60 minutes before. Many athletes use both, so count the total.
Most people do not need to. Caffeine taken before the start is still working at the finish of a 60 to 90 minute race. If you expect to race longer than about 90 minutes and plan to take a gel anyway, a caffeinated gel on the run after station 4 or 5 is an option.
It can. Research suggests a mug of coffee at least 9 hours before bed and a 200 mg dose at least 13 hours before bed to avoid losing sleep. For waves after about 14:30, take 100 mg or less, or skip it, especially if you race again the next day.
Only if you know exactly how much caffeine is in it and you have used it before hard training. Many pre-workouts contain 200 mg or more plus other stimulants. Added to your morning coffee, that can push you past safe limits and cause shaking or stomach trouble.
General guidance for healthy adults, not medical advice. Talk to a doctor or registered dietitian if you have a health condition, take medicines or have special dietary needs. Caffeine advice is for healthy adults only. EFSA's safe limit is 200 mg in one dose and 400 mg in a day.
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