Brushing your teeth can create an alerting effect on the body and mind, resulting from a combination of chemical signals and physical inputs. This feeling of increased wakefulness is a direct consequence of the ingredients found in most common toothpastes and the routine associated with oral hygiene. The boost in energy comes from stimulating the nervous system and altering environmental cues that signal the body’s readiness for activity.
How Menthol Tricks Your Brain
The primary chemical factor contributing to alertness during brushing is the menthol found in mint-flavored toothpaste. Menthol simulates a cold sensation by interacting with specific sensory proteins, even though it does not actually lower the temperature in your mouth. This chemical acts on a specialized sensory receptor protein known as Transient Receptor Potential Melastatin 8, or TRPM8.
TRPM8 channels are naturally activated by temperatures below approximately 79 degrees Fahrenheit (26 degrees Celsius). When menthol binds to these receptors on nerve endings in the mouth, it triggers the same neural signal that actual cold would produce. The brain interprets this signal as a sudden drop in temperature, creating the characteristic “cool” or tingling feeling associated with mint.
The Physical Act of Brushing
Beyond the chemical stimulation of menthol, the physical elements of the brushing routine contribute to wakefulness. The mechanical action of the toothbrush moving across the gums and teeth provides direct sensory input to the nervous system. This stimulation, combined with the change in posture from lying down to standing upright at the sink, signals the body that an activity is underway.
The temperature of the water used for rinsing can also play a role, especially if it is cool or cold. Furthermore, the light in the bathroom provides a significant alerting cue. Many modern bathrooms use bright, white, or blue-spectrum lighting, which influences the body’s internal clock. Exposure to this type of light acts as a strong signal to the brain that it is daytime, reinforcing wakefulness.
Brushing Before Bed
Performing an alerting activity right before attempting to sleep can interfere with the transition to rest, particularly if it involves strong chemical and light stimuli. The combination of menthol’s cooling signal and bright light exposure works against the body’s natural wind-down process. Light, especially blue light, is known to suppress the production of the hormone melatonin. Melatonin is naturally released as light levels drop and signals the onset of drowsiness.
To minimize this stimulating effect when brushing close to bedtime, individuals can adjust certain parts of the routine. Using warm water instead of cold water for rinsing avoids unnecessary thermal stimulation. Switching to a non-mint or milder-flavored toothpaste can limit the intense TRPM8 activation caused by menthol. Dimming the bathroom lights or using an amber or red nightlight instead of bright overhead lights can also reduce the suppression of melatonin, allowing the body to prepare for sleep more effectively.