What the research says
The International Society of Sports Nutrition’s 2021 position stand concludes that caffeine consistently improves endurance performance when taken in doses of 3–6 mg per kg of body mass, most commonly about 60 minutes before exercise. Doses as low as 2 mg/kg can help, and higher doses add side effects without clear extra benefit.
Caffeine dose by body weight
| Body weight | 2 mg/kg | 3 mg/kg | 4 mg/kg | 6 mg/kg |
|---|---|---|---|---|
| 50 kg (110 lb) | 100 mg | 150 mg | 200 mg | 300 mg |
| 55 kg (121 lb) | 110 mg | 165 mg | 220 mg | 330 mg |
| 60 kg (132 lb) | 120 mg | 180 mg | 240 mg | 360 mg |
| 65 kg (143 lb) | 130 mg | 195 mg | 260 mg | 390 mg |
| 70 kg (154 lb) | 140 mg | 210 mg | 280 mg | 420 mg |
| 75 kg (165 lb) | 150 mg | 225 mg | 300 mg | 450 mg |
| 80 kg (176 lb) | 160 mg | 240 mg | 320 mg | 480 mg |
| 90 kg (198 lb) | 180 mg | 270 mg | 360 mg | 540 mg |
| 100 kg (220 lb) | 200 mg | 300 mg | 400 mg | 600 mg |
Red values exceed the 400 mg daily guideline on their own.
How much caffeine is in…
| Source | Caffeine | Data from |
|---|---|---|
| Brewed coffee, 8 oz (237 ml) | 96 mg | Mayo Clinic |
| Espresso, 1 oz (30 ml) | 63 mg | Mayo Clinic |
| Instant coffee, 8 oz | 62 mg | Mayo Clinic |
| Energy shot, 2 oz | 200 mg | Mayo Clinic |
| Caffeinated gel (typical range) | 25–100 mg | manufacturer labels |
| Maurten Gel 100 CAF 100 | 100 mg | maurten.com |
Coffee varies a lot: the FDA notes a 12 oz cup of brewed coffee can contain 113–247 mg. Gels and tablets give a known dose.
Who should be careful. People who are pregnant (EFSA: up to 200 mg a day), have heart rhythm problems, anxiety, high blood pressure or take interacting medicines should talk to a doctor. Caffeine can cause jitters, a racing heart, stomach upset and poor sleep. About 1,200 mg taken rapidly can be toxic.
Combine with your fuelling plan in the race fueling calculator and carb loading calculator.
Last reviewed: September 2026 · Health disclaimer