Featured Image Credit: towfiqu ahamed via Getty
People on social media have been warned to stay away from a common oral hygiene habit after they've finished a workout, as there's a surprising clash that you likely won't have considered before.
It can sometimes be hard to know if a habit you've been doing as part of your daily routine is actually more harmful than expected, yet there are some things that seem normal yet are actually detrimental to your health.
This is especially the case in conjunction with workouts and exercise, as you could be sacrificing the benefits of physical activity without even knowing which is definitely not want you want.
That's why a warning from infamous biohacker Bryan Johnson is definitely something you should consider, as while his regular advice is largely outside of what most people would consider, this could save you a lot of frustration down the line.
Advert
As shared on his X profile, Johnson urged people to avoid using mouthwash after a workout, as he advises that "rinsing with antiseptic mouthwash after exercise can blunt the benefits of a workout."
A reminder to avoid using mouthwash after a workout.
— Bryan Johnson (@bryan_johnson) January 13, 2026
Rinsing with antiseptic mouthwash after exercise can blunt the benefits of a workout.
Antibacterial mouthwash cut over 60% of exercise’s blood-pressure-lowering effect after 1 hour. And fully canceled it 2 hours… pic.twitter.com/XYw5dVqYQj
Adding to this, he illustrates that "antibacterial mouthwash cut over 60% of exercise's blood-pressure-lowering effect after 1 hour. And fully canceled it 2 hours post-exercise."
While it might seem odd at first to take mouthwash after physical exercise, a large proportion of people do their workouts as soon as they get up, and there's a chance that you'd just use mouthwash before heading to work or starting your day post-workout.
Key to Johnson's advice is a study published in the Free Radical Biology and Medicine journal, which measured the blood pressure of study participants after a workout when using antibacterial mouthwash.
"Post-exercise hypotension (PEH) is a common physiological phenomenon leading to lower blood pressure after acute exercise, but it is not fully understood how this intriguing response occurs," the study outlines.
"This study investigated whether the nitrate-reducing activity of oral bacteria is a key mechanism to trigger PEH," and that is indeed the case following a trial of 23 'healthy individuals', with Johnson representing the results in his original post.
"These findings show that nitrite synthesis by oral commensal bacteria is a key mechanism to induce the vascular response to exercise over the first period of recovery thereby promoting lower blood pressure and greater muscle oxygenation."
Many in the replies to Johnson's post are wondering whether it's ever a good idea to use mouthwash considering what the study argues, and while it's generally 'fine' to use under most circumstances, you'll want to avoid it within the proximity of a workout — both before and after.
