Does chlorophyll freshen breath? A runner in one of our groups asked me this after a long Sunday run, so I went back through what has actually been tested.

Does chlorophyll freshen breath? What was tested

Chlorophyll gum, mints and toothpaste were huge in the early 1950s, and the craze faded within a few years when the evidence did not hold up. A 2014 study measured garlic breath and found raw apple, parsley, spinach and mint reduced the smelly compounds. Chlorophyllin did not. There is no good modern trial showing chlorophyll fixes bad breath that starts in the mouth.

Propel Health Australia covers the history and the studies in chlorophyll for bad breath.

Why training gives you bad breath

Breathing hard through your mouth dries it out, and a dry mouth lets bacteria on the tongue produce sulphur compounds. Sports gels and sweet drinks feed those bacteria. Long fasted sessions can add a different smell as your body burns more fat.

What actually helps

• Sip water through the session, not just at the end.
• Rinse with water after gels or sports drinks.
• Clean your tongue when you brush.
• Eat something after long sessions instead of running on empty all morning.
• See your dentist if bad breath hangs around.

A simple routine for long run days

Before you head out, drink a glass of water and eat something small if the run is longer than an hour. Carry water or plan a route past a bubbler, and take small sips every 15 to 20 minutes rather than gulping at the end. If you use gels, follow each one with a mouthful of water to rinse the sugar off your teeth. Afterwards, have a proper meal within a couple of hours, brush your teeth and give your tongue a scrape. It sounds basic, and it is, but this routine does more for training breath than any product on the shelf, and it is better for your recovery as well.

Where chlorophyll fits

If you enjoy a glass of chlorophyll water, it is one more reason to drink water, and that genuinely matters for a dry mouth. Just do not expect it to replace a toothbrush. If you want to try it, you can buy liquid chlorophyll from Propel Health Australia. It is unflavoured and uncoppered, with no preservatives or additives.

Quick answers

Do chlorophyll mints work?

The mint does the masking. There is no good evidence the chlorophyll adds anything.

Will chlorophyll stain my teeth?

It can. Dilute it and use a straw.

More: chlorophyll water after training, chlorophyll capsules or liquid, what to eat before training.

Written by Grant Jenkins, Accredited Exercise Physiologist at PropelFit, Samford. General information only, not individual advice. Check with your GP before starting a new supplement, especially if you are pregnant, take medication or have a medical condition.