Despite being applied to the armpits, they are different products and work in different ways.
The combination of heat and activity often results in increased sweating. Sweat feels great: It’s our personal evaporative cooling system. Most people eliminate at least half a liter a day, and that’s without even counting intense exercise.
Unfortunately, sweating can also worsen body odor. To control it, many of us use a daily antiperspirant or a deodorant, very different from each other.
Knowing this difference can help you adjust your personal hygiene products and stay free from unpleasant smells.
Sweat doesn’t smell bad
To understand how underarm products work, you must first understand where does the unpleasant odor come from. The sweat released by the body is actually odorless. It comes mainly from two types of glands: eccrine and apocrine.
Eccrine sweat glands, responsible for most sweat, are distributed throughout almost the entire body. They tend to release sweat that is mostly watery, essential for thermoregulation. This sweat also contains electrolytes and small amounts of other substances that, as a rule, do not cause bad odors.
The apocrine sweat glands, located mainly in the armpits and in the inguinal region, produce more oily sweat, with proteins, sugars and lipids. This sweat is also initially odorless.
However, several types of bacteria that live on the skin feed on this sweat and, in doing so, produce volatile and odorous substances. This is what generates body odor and the smell of some of these compounds can be detected by the nose in concentrations of the order of trillionths of a gram per liter of air. Apocrine glands tend to become active with the onset of puberty.
To combat these odors, we use antiperspirants or deodorants. Although the terms are often used synonymously, each name actually describes the precise way in which these products work.
What do antiperspirants do?
Generally speaking, all antiperspirants work in a similar way. They contain active ingredients that prevent the body from releasing sweat right from the start.
The ingredients responsible for this effect are normally salts with metals, most often aluminum chlorohydrate, aluminum sesquichlorohydrate, aluminum chloride or a zirconium-aluminum compound.
These substances combine with water and other molecules in the sweat gland duct, forming a temporary plug that prevents sweat from reaching the surface of the skin. As a result, bacteria are deprived of the substances they feed on to produce unwanted odors.
What do deodorants do?
Deodorants work in another way: they let sweat reach the skin, but prevent the odor from being released or becoming noticeable. This is achieved through different ingredients.
Some deodorants include antimicrobial agents, designed to reduce the microbial population responsible for producing odorous molecules. Others are perfumes, designed to mask bad odors.
Sometimes, odor-absorbing compounds are also added, which bind to volatile molecules and, in some cases, also help to absorb moisture.
Finally, certain active ingredients can alter the local pH of the skin, making the environment less favorable for the growth of bacteria.
Other approaches — still in development — seek to inhibit the production of odors by bacteria or neutralize odor precursors before they are consumed.
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In addition to the main ingredients, an underarm product can be expected to include other additives to act as preservatives, provide a pleasant fragrance, facilitate application and improve the feel of the product on the skin.
If the goal is just to stop the smell, a deodorant can do the trick. If you also want to sweat less, what you need is an antiperspirant. If you can’t decide, many products combine the two strategies — for example, an antiperspirant with a strong fragrance, or antiperspirants with antimicrobial agents.
As with many consumer products, some people have personal preferences — or prefer the results of one approach over another. As we age and change habits, the body may react differently to these products, so some “trial and error” may be necessary — and, in some cases, seeking medical advice.
What about “natural” deodorants?
Despite a rumor sparked by a fraudulent email, evidence-based research indicates that aluminum-based antiperspirants are safe and pose no health risks.
Still, “natural” deodorants are popular for several reasons. Although they sometimes use different active ingredients than “normal” deodorants, the mode of action is usually the same — antibacterial, odor masking, moisture absorbing, or a combination of these strategies.
A common active ingredient in “natural” formulations is sodium bicarbonate, used to absorb moisture and odor and to modify the pH of the armpits. Certain essential oils, used for their antimicrobial properties and aroma, are also common.
It is important to note that a product being “natural” does not necessarily mean it is safer. In fact, some alternative ingredients have not been tested as thoroughly for safety. Others present risks similar to those of synthetic counterparts — for example, the possibility of bacteria developing antimicrobial resistance to both synthetic ingredients and natural ingredients, including essential oils.
