Sweat is a hallmark of summer, and if you’re not careful, body odour can be, too.
But it doesn’t have to be this way, and while deodorant might be enough to keep the smell at bay, there are an overwhelming number of options on the market for your underarms, from traditional antiperspirants to natural deodorants and even acids.
But what about everywhere else on your body where a funky scent might pop up? How does what we eat affect our smell, and can we really just drink chlorophyll to smell good, like TikTokkers might have you believe?
First, it’s helpful to understand where the stench comes from. “Sweat glands and bacteria are the primary causes of body odour. Everyone’s sweat gland count and activity are different: The more glands and activity, the higher the risk of body odour,” explains Geeta Yadav, a board-certified dermatologist.
Sweat glands exist all over the body, but those located in areas with more hair follicles, like armpits, contain more fats, proteins and sugars than the sweat that might appear on your forehead, for example. This is the sweat that’s most responsible for body odour – but sweat alone isn’t smelly.
“Bacteria, which naturally live on your skin, thrive in damp and dark conditions (such as those created by tight workout clothes, or just the nature of the armpit!). Bacteria break down keratin proteins on your skin and cause odur,” Yadav explained.
So, how do we keep from smelling bad?
Deodorants and antiperspirants for your underarms
While sometimes used interchangeably by the layman, deodorants and antiperspirants are not the same. Antiperspirants stop you from sweating, which means your armpits won’t be an ideal environment for bacteria and odour to thrive, so you’ll have no sweat and no smell. Deodorants don’t stop you from sweating, but they do make you smell better, either by covering up the scent of body odour, or helping inhibit it in the first place. Both of them are well-proven to keep armpits smelling fresh.
Even so-called natural deodorants, often ridiculed for their inability to prevent BO, can mask bad smells as long as your expectations are realistic: You will still sweat, and when switching to a natural deodorant you may encounter a few weeks of heightened armpit odour while pits “detox” before it begins to work. Look for ones with antibacterial ingredients like coconut oil and baking soda to reduce moisture.
Recently, though, antiperspirants, which use aluminium-based compounds, have come under fire for purportedly contributing to certain diseases, though the science falls flat and most experts agree they are safe.
“Studies do not show a correlation between aluminium-based antiperspirants and health conditions such as breast cancer and Alzheimer’s disease, but ultimately, if using an aluminium-free formula gives you peace of mind, go for it,” Yadav says.
Chris Callewaert, a senior postdoctoral researcher at Ghent University and an expert on body odour (he even uses the handle Dr Armpit online), likes the trend of moving away from aluminium antiperspirants, but not due to the scary health rumours. Instead, his research has found that antiperspirants negatively impact the armpit microbiome. This disruption can ultimately increase odour-causing bacteria. “Don’t use antiperspirant if you have slight malodour – this might make things worse in the long run,” he warns.
“Sweating is actually a very natural phenomenon and should not be needlessly blocked,” he added. Unless you have hyperhidrosis, a condition in which armpits sweat excessively, he recommends moderate use of regular deodorant instead.
For fans of acid deodorants, which are made with ingredients like lactic and mandelic acid that are typically reserved to exfoliate the face and smooth skin, here’s some good news: Callewaert approves.
As the name applies, these products are acidic, just like the natural pH of the armpit. Typical deodorants tend to be more alkaline, so by keeping the armpit in balance, it leads to a healthy underarm microbiome and less odour. The exfoliating nature of acid deodorants help keep armpits clean, too, by removing sweat and odorous molecules better than water alone can.
Deodorant for everywhere else
While the focus of body odour is typically on the armpits, it’s not the only area that can produce smell — the same odour-producing glands that are located in the armpits can be found in the groin area. It’s better to save your deodorant for use in the armpits only. “I would not recommend it, as it will impact the microbiome, and some deodorants can really shift the microbiome to a worsened odour,” Callewaert says.
Instead, perfumes or essential oils can be used, as they have less impact on the microbiome along with a long-lasting effect.
“I’d recommend using deodorant wipes like those offered by Dove instead of a traditional stick. It won’t contain antiperspirant, but it will help refresh and combat odour,” Yadav says.
There’s also another alternative: deodorising body sprays, creams and soaps that use pre- and probiotics to prevent BO. The pre- and probiotics directly interact with your skin’s microbiome, and a healthy microbiome – which these bacteria contribute to – will produce less odour. These are already being used in products like OffCourt and other body deodorants.
Not just any probiotics will work, though. “The lactobacilli and bacilli that are used now do not really occur naturally on the skin, and definitely not in high amounts,” Callewaert explains. “So they will only be transiently present when applied.” Probiotics also need to be alive to be effective, which isn’t often the case in deodorants or body washes.
How the foods you eat can contribute to BO
It’s not only what we put on our bodies that affects how we smell, but what we put in it, too. “Food can have a big impact on the skin microbiome and odour development,” Callewaert says. In fact, his research on the gut-skin axis found nearly all skin disease has a link with the gut.
What’s good at preventing body odour is obvious: “It will be no surprise that we also found that the daily consumption of vegetables leads to an improved body odor, a less musty, less sour and less bad body odour, as well as significantly more non- or good-odorous bacteria in the underarms,” Callewaert says.
“Drinking lots of water, eating hydrating foods like cucumber and watermelon, and even eating citrus can help eliminate those bad odours,” Yadav says.
The wrong foods have the opposite effect. “Some foods contain compounds that your body can’t break down, which means they get released from your body through sweat,” Yadav explains. She named alliums, like onions and garlic, along with alcohol as the most common offenders.
Callewaert’s research showed that frequently eating meat and fast food led to worsened underarm odour, “as well as a higher abundance of malodour-associated bacteria in the underarms.”
While TikTokkers claim chlorophyll helps prevent body odour, Callewaert says he hasn’t studied it. However, he has his doubts that any one ingredient would make a big difference. “In my opinion, it is really the bulk of what we eat that will have the biggest impact on the skin microbiome and odour development. Consuming one ingredient in low concentrations, like chlorophyll, will probably only have a marginal effect, if there is any at all,” he said. It should be noted that some older studies have looked at chlorophyll’s deodorising effects, and the results are dicey at best.
In-office treatments for your armpits
Some of the most effective ways to stop sweating (and therefore the odour that comes along with it) are treatments that need to be done by a professional. The first is Botox. The same treatment used to reduce and prevent wrinkles (among other uses) can be injected into the armpits to stop sweating for about four to six months. “Hyperhidrosis treatments like Botox, which temporarily paralyses the sweat gland activity, or MiraDry, which permanently destroys sweat glands, can go a long way towards reducing sweat and thus body odor,” Yadav says.
MiraDry is a newer treatment that, while more costly than Botox, can last much longer. It’s also needle-free. It works by destroying sweat glands via energy waves.
Chill out
While easier said than done, keeping stress low can help, too. “Stress has an impact on odour development: Stress releases adrenaline, which has a direct impact on the apocrine sweat glands. These are the precursors for body odour. The skin microbiome will break down the apocrine sweat and lead to a burst of malodor,” Callewaert says.
Staying body odour free doesn’t necessarily have to be complicated, but if you find that you’re smellier than you like, following just a few of these tips can make a big difference.