Caffeinated Energy Gels

Most caffeinated gels contain between 20 and 50 milligrams of caffeine per packet, though some concentrated formulations go up to 75 or 100 milligrams. For reference, a standard cup of brewed coffee contains roughly 80 to 100 milligrams. The amount per gel is listed on the nutrition label, and tracking your total caffeine intake across all sources during a race is necessary to stay within the research-supported range of 3 to 6 milligrams per kilogram of body weight.

Caffeine reaches peak blood concentration within 30 to 60 minutes of ingestion. Many athletes save caffeinated gels for the second half of a race, when fatigue and mental fog are most pronounced. For events under two hours, one caffeinated gel 30 minutes before the start may be sufficient. For longer events, spacing two to three caffeinated gels across the final hours is a common approach. Using only caffeinated gels from start to finish raises total caffeine intake and increases the chance of side effects.

You can, but you must track total caffeine across all sources. Research supports performance benefits at 3 to 6 milligrams per kilogram. For a 70-kilogram athlete, that is 210 to 420 milligrams total across the event. A pre-race coffee providing 100 milligrams plus three caffeinated gels at 40 milligrams each totals 220 milligrams, which falls within range. Exceeding 6 milligrams per kilogram increases the likelihood of anxiety, elevated heart rate, and gastrointestinal distress without additional performance benefit.

Caffeine has a mild diuretic effect at rest, but published research shows this effect is negligible during exercise when athletes maintain normal fluid intake. A 2014 study in PLOS ONE found no difference in hydration status between caffeinated and non-caffeinated groups during exercise. Caffeine in the amounts found in energy gels does not meaningfully alter fluid balance during activity, provided you continue drinking to thirst or according to your hydration plan.

Caffeine has a half-life of three to seven hours, meaning half the dose is still circulating hours after ingestion. A gel containing 50 milligrams of caffeine consumed at 7 PM still has roughly 25 milligrams active in your system at 10 PM or later. For evening events, using non-caffeinated gels or limiting caffeinated gels to early in the race reduces the chance of disrupted sleep afterward. Poor post-race sleep impairs the recovery process that follows competition. (edited)