When summer hits, the combination of heat and activity often result in increased sweating. Sweat is great – it’s our personal evaporative cooling system. Most of us will sweat out at least half a litre each day, and that’s before any intense exercise.

Unfortunately, sweating can also exacerbate body odour. To control this, many of us use an antiperspirant or deodorant every day. Even though we apply both to our underarms, the two products are actually distinct and function in different ways.

Knowing this difference can help you troubleshoot your personal hygiene products – and stay stink free.

To understand how underarm products work, we first need to look at where the unpleasant odour comes from.

The sweat our bodies release is actually odourless. It comes primarily from one of two types of glands: eccrine and apocrine.

Eccrine sweat glands, responsible for the greatest amount of sweat, are located over most of the body. They tend to release a mostly water-based sweat primarily responsible for our thermoregulation. This sweat also contains electrolytes and small amounts of other substances that typically don’t result in bad odours.

The apocrine sweat glands, found primarily in the armpit and groin regions, produce sweat with a more oily composition, containing proteins, sugars and oils. This sweat is also odourless at first.

However, several types of bacteria that live on the skin feed on this sweat, and in........

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