What makes us sweat?
Our skin has two types of sweat glands: Eccrine glands, found over most of the body, emit liquid made mainly of water and electrolytes; and apocrine glands, concentrated in areas abundant with hair follicles (underarms, genitals, scalp), produce liquid containing lipids, proteins and steroids. Eccrine glands  help regulate temperature when the body is too warm (due to weather, exercise or fever), while apocrine glands contribute sweat stimulated by emotional stress, nervousness or arousal. There's no correlation between overactive glands and smelliness; many people who perspire excessively emit very little odour.

Stress sweat
"Stress sweat" from apocrine glands is broken down by the bacteria on our skin into compounds that are responsible for body odour, explains Hamilton dermatologist Dr. Peter Vignjevic. So why do some people smell more than others? George Preti, who studies human body odours at the Monell Chemical Senses Center in Philadelphia, says genes likely play a role. Diet may as well: One study indicates meat eaters give off a stronger odour.  

Combating sweat
Deodorants fight odour using a combination of fragrance and antibacterial agents, while antiperspirants contain compounds (generally, aluminum salts, with clinical brands containing the highest concentrations) that temporarily block sweat glands. And no, sweating doesn't get rid of toxins, says Dr. Kevin Smith, a Niagara Falls, Ont., dermatologist. (That  work is carried out by your liver, intestines and kidneys.) Nor is there any evidence that the chemicals in antiperspirants, in the amounts used, pose any health risks, notes  Dr. Vignjevic. And what's behind your suspicion that your body "stopped" your deodorant from working? According to Dr. Smith, it's likely that you're not putting on your antiperspirant properly; these products perform best when applied to paper-dry skin before bed. If you'd also like to dab it on after your morning shower, he suggests gently blow-drying your armpits beforehand.

DIY deodorant?
Yes, if you're crafty, you can make your own deodorant, using coconut oil, cornstarch, baking soda and essential oil. Does it work? Possibly. The powder absorbs moisture and the essential oil may mask the smell. However, yeast (the type that causes uncomfortable skin infections) can feed on the starch, and people with sensitive skin may react to essential oils. Find a recipe to try at coconutoil.com/home-made-coconut-oil-deodorant.

Is stress making you sweat? Check out how stress affects your body.

This story was originally part of "The Underarm" in the June 2015 issue.             Subscribe to Canadian Living today and never miss an issue!