How they work

We all sweat, and that can lead to body odor, stains on our clothing and more. No one wants to be near you if your armpits smell bad, either. To combat these problems, deodorants and antiperspirants were created. Deodorants help keep you smelling good by masking body odor and targeting the bacteria that creates odors in the first place, while antiperspirants work by stopping you from sweating. How do antiperspirants work beyond that, though? How do they stop you from sweating?

How Antiperspirants Work

First, understand that antiperspirants work slightly differently, depending on whether you’re using a solid or a spray. In a solid stick, the active ingredient (an aluminum salt, or derivative) enter the cells around eccrine glands (the most numerous and active type of human sweat glands). There, it draws in water. The more water drawn in by the aluminum, the more the cell swells. Eventually, it swells to the point that the eccrine gland is effectively squeezed shut.

Over time, though, the cells eventually reach equilibrium. When this happens, the water inside the cell evaporates through osmosis, and the swelling reduces. This releases the pressure on the eccrine gland, and it begins to emit sweat again. The only option now is to reapply the antiperspirant.

Spray antiperspirants work in a similar way. They still use an aluminum component, but they lack some of the others found in a stick type antiperspirant, such as wax and liquid emollients.

Some antiperspirants take things a step further. They combine not only the cell swelling capabilities of aluminum, but include additional ingredients that, when mixed with sweat, form a gel. This gel-like substance ultimately plugs up the sweat gland, acting like a cork and preventing sweat from leaving the gland even when the cells around the gland are not swollen from exposure to aluminum chloride. Eventually, the plug comes out though, and you will need to reapply the antiperspirant.

The Problem with Aluminum

Aluminum, the active ingredient in pretty much all conventional antiperspirants, has some potentially problematic side effects. Several brands and formulations have been discontinued due to the metal’s harmful effects. For instance, the first-ever antiperspirant in the US, called Everdry, was ultimately discontinued because of the skin lesions it created in users. Other side effects to higher concentrations of aluminum in antiperspirants include dermatitis, and, in rare but serious cases, kidney damage (linked to aluminum chloride, specifically).

While the US government, UK government, EU regulators and other official bodies have not found any proven link between them, the aluminum content in antiperspirants has been linked tentatively to many health problems, ranging from an increased risk of cancer, to Alzheimer’s disease. Again, there is no proven scientific link here, but the mounting evidence should make you think twice before using an antiperspirant with aluminum as the active ingredient (all conventional brands use some type of aluminum, whether that’s aluminum chloride, aluminum hydroxybromide, or something else).

Ultimately, antiperspirants help keep you from sweating, but their cons may outweigh their pros. Cancer and Alzheimer’s aside, there are benefits to sweating freely.