For most people, the daily personal hygiene routine includes the use of deodorants or antiperspirants to avoid unpleasant odors caused by perspiration.
If you use these products, it is quite possible that you have already heard that they can be harmful to your health, due to the amount of aluminum they contain and because they block pores.
In recent years, there has been a growing supply of natural deodorants on the market that promise to be less aggressive on the skin, without alcohol or aluminum — substances supposedly linked to diseases such as breast cancer.
These products are much more expensive, and the price can be three or four times higher than that of a traditional deodorant or antiperspirant.
Is it worth investing in these products? Are the ones we used really dangerous for our health?
BBC journalist Greg Foot spoke to dermatologist Adil Sheraz and Barbara Olioso, a chemist specializing in the composition of natural products, to understand the science behind these claims and what marketing is.
First, it’s important to understand how sweating works.
“Sweating is the mechanism that regulates our body temperature”, explains Sheraz. “Sweat releases fluids, basically water with electrolytes, salt. When the body heats up, you release this fluid on the surface of the skin, it evaporates into the air and thus takes the heat away, reducing body temperature.”
Furthermore, we can sweat in situations that cause us stress, nervousness or anxiety.
It is not the perspiration itself that generates the odor, but rather the interaction of sweat with the bacteria that live on our skin.
“We have approximately 2 to 4 million sweat glands in the body. Some are called eccrine sweat glands, which are present in almost the entire body, release water and salts and do not have any type of odor”, says the dermatologist.
Others are apocrine sweat glands, which fulfill a slightly different function and are present in the armpits, groin, scalp and some areas of the face.
“These glands also produce sweat, but their composition is a little different: they contain fatty acids, carbohydrates, some complex lipids and steroids. When this sweat is released, the bacteria that normally live on our skin feed on these components and this creates the odor that you associate with perspiration,” says Sheraz.
To avoid bad odor, we can generally use three types of products: deodorants, antiperspirants and natural deodorants.
Deodorants reduce odor by killing bacteria or masking the odor they generate, but they have no impact on the amount of sweat a person produces.
Natural ones, which are presented as the healthiest option, are usually made from a “mixture of natural antibacterial products (such as sage extract or zinc derivatives) with sweat-absorbing ingredients (various types of starches) and sodium bicarbonate “, explains Olioso.
Unlike the latter, antiperspirants – predominantly based on aluminum compounds – form a temporary covering in the sweat ducts and interrupt their flow to the skin’s surface.
Can blocking underarm pores be harmful? And does this have a negative effect on our health?
“If we think about the number of sweat glands we have, those in the armpits only represent between 1% and 2% of the total. Therefore, blocking these pores with aluminum will not have a harmful effect on the sweat you produce,” says Sheraz.
“If you need to cool off, you will cool off because your body has plenty of other sweat glands to do that.”
As for aluminum, although there are some studies that have in the past linked the product to certain medical conditions, such as breast cancer or dementia, Sheraz says, “if we look at all these studies, we will see that there is no conclusive proof that aluminum causes any ( these conditions)”.
Aluminum was developed as an antiperspirant at the beginning of the 20th century, meaning it has been in use for over a hundred years. A possible harmful effect would have already been proven in studies, argues Sheraz.
Antiperspirants can cause irritation to the underarm skin, due to the other chemicals they contain. But this, highlights the dermatologist, is due to not using the product correctly.
And what would be the correct way?
The best way to use a product that contains aluminum is to ensure your underarms are completely dry.
If they are wet, the aluminum chloride will react with the water and produce hydrochloric acid that will irritate the skin.
For this reason, Sheraz recommends applying antiperspirant at night and washing your underarms the next morning.
Over time, aluminum will build up in ducts and block them. So, even if you apply it at night, you will see the results the next day, as you will sweat less.
But, according to Sheraz, “this takes at least a week to take effect.”
So the best option is ultimately a matter of preference.
“It’s a question of having a hierarchy of values”, says chemist Barbara Olioso.
“If long-term performance and protection are key to you, choose an antiperspirant. If you have a more environmentally friendly drinking style and don’t mind weaker, longer-lasting performance, opt for a natural one,” he says, leading also take into account the type of packaging of the product.
