Carbohydrate mouth rinsing and endurance: benefits and limits

The hypothesis doesn't rest on absorbed energy, since the drink is spat out. Receptors in the mouth are thought to detect carbohydrates and activate brain regions linked to reward and motor control. A 2013 review mentions activation of regions such as the insula, the orbitofrontal cortex, and the striatum. This mechanism remains a research-level explanation.

The largest synthesis, published in 2022, analyzed 34 studies on maltodextrin. Using a conventional method, rinsing improved performance compared with placebo, with a small effect (standardized difference 0.15). With a more conservative model, the estimated effect remained small (0.17) but the confidence interval included no effect at all.

In cyclists, a meta-analysis of 13 studies and 16 trials found an increase in average power output, but no improvement in the time to complete the event. This nuance matters: producing slightly more watts on a laboratory test doesn't necessarily mean saving time in a race.

Early studies suggested a clearer effect when glycogen stores were low, for example fasted in the morning. A 2025 meta-analysis, limited to trials conducted after a meal, nonetheless found a small effect (g = 0.18), more pronounced in aerobic exercise, with a maltodextrin solution, a rinse of 10 seconds or less, and after a carbohydrate-rich meal. The authors judge the overall certainty of the evidence to be low. So it isn't possible to predict for whom rinsing works best.

Most trials use a maltodextrin solution at about 6 to 6.4%, held in the mouth for 5 to 10 seconds, then spat out. Rinses are repeated several times during the effort, at a frequency that varies by protocol. These are research parameters, not an official dose.

To test the method:

1. 01choose a session of about an hour close to your goal;
2. 02never try it for the first time in competition;
3. 03compare it with a session without rinsing, under the same conditions;
4. 04don't change your meal, drink, and pace all at once;
5. 05note how you felt, digestive tolerance, and the result.

For an effort of about an hour, either rinsing or small amounts of carbohydrate can improve performance. Beyond that, ingestion becomes the reference strategy: up to about 60 g of carbohydrate per hour for 2 to 3 hours of effort, and about 90 g per hour for longer events, using several types of sugar. Rinsing can help out when the stomach can no longer tolerate anything, but it provides no fuel to the muscles.

To build a fueling plan, see carbohydrates before, during and after exercise and up to 120 g of carbohydrate per hour.