The Smelly Truth about Antiperspirants

Have a body odour problem? Surprisingly antiperspirants are not the answer.

Antiperspirants have been widely used for over 60 years, but new research from the Archives of Dermatological Research suggest that they may actually make you smell worse!

new smell- deodorant

(Image credit: Alan [CC BY-NC 2.0] via Flickr)

The research from the University of Ghent showed that individuals that used antiperspirants had an increase in the smelliest type bacteria that lives in the armpits called Actinobacteria, specifically Corynebacteria. It is suggested that the aluminium compounds in the antiperspirants kill good odourless bacteria like Staphlococcus allowing the smelly ones to flourish. Deodorants on the other hand, reduced the levels of both types of bacteria.

The study involved 8 individuals refraining from using antiperspirant or deodorant for a month. They compared the results to a person who was told to use antiperspirants and not previously use them.

The experiment has been criticized due to the small sample size with only 9 people in total taking part. But the scientists say that these are simply initial findings and further research will be conducted to substantiate the findings.


Where does body odor come from?

Our skin has a layer of friendly or commensal bacteria on its surface called our microbiome. These bacteria help us to stop harmful bacteria from colonizing and taking over our skin.  When we sweat, the bacteria in our armpits consume the amino acids and lipids in the sweat and create smelly compounds that we detect as body odour. Sweat itself doesn’t have any scent.

Antiperspirants work by blocking sweat glands with aluminum based compounds such as aluminium chlorohydrate. This prevents sweating so bacteria have no food source to produce the smelly gases from. Deodorants on the other hand use antimicrobial agents to kill bacteria and mask bad odours they create with better smelling ones.


Staphlococcus epidermidis, an odourless inhabitant of our skin (Image Credit: Microbe World [CC BY-NC-SA 2.0])                


Actinobacteria, the smelly bacteria on our skin (Image Credit: AJ Cann [CC BY-NC 2.0])

What can people with chronic body odour do?

Since neither of these address the bacterial composition of the armpits directly, they are not long-term solutions for people who need it the most, sufferers of chronic body odour or bromhidrosis. The researchers shifted their focus to armpit bacterial transplants in order to restore the bacterial balance without the use of antiperspirants or deodorants.

Researchers successfully transferred armpit bacteria from a person without body odour to the washed armpit of a relative of theirs with severe body odour. This led to an almost immediate and permanent reduction in the pungency of his scent with a simple and non invasive procedure.

Problems occur when armpit bacteria transplants are performed between people who are not closely related. This may be due a wide range of factors including differences in skin composition and hairiness.

What should we take away from this?

In the long term, a change to deodorants from antiperspirants would probably be beneficial for your armpit bacterial ecosystem. But wearing antiperspirants is still more socially acceptable than not using any at all. It really comes down to who you love more, your armpit bacteria or your potential date.

13 Responses to “The Smelly Truth about Antiperspirants”

  1. wesleyw says:

    Hey Jess,
    Thank you!
    I guess there’s a difference between a normal amount of body odour that we use deodorants for and those with extremely bad body odours which this method is targeting.

    There is an unrelated disease that can’t be cured with this method called trimethylaminuria in which the person and their body fluids smell like fish. It just shows that body odour can be devastating bad body odour can be to a person’s life and their relationships with friends and family and how we can take it for granted.

    That point you raised is really interesting, we are so much more hygienic we are compared to even 50 years ago. It introduces the possibility we may be doing more harm than good in using so many products to clean ourselves and our surroundings is something new we have to be aware of.

  2. jfrench says:

    Hi Wesley,

    Thanks for such an entertaining post! I have images in my mind of people rubbing armpits to transfer healthy bacteria to each other… but Im sure it wasn’t as crude as that!

    I have never thought about the bacterial community living under my arm until I read your post!

    I wonder when we decided armpit sweat was such a problem and when deodorant became the social norm?

  3. wesleyw says:

    Hey Liv,great question 🙂
    The microbiome is an emerging field and more research is currently going into establishing its composition before more specific research like this was performed. The blog post used a simple “proof of concept” research paper with a tiny sample size.

    The are more studies in the works though establishing the effects of Triclosan, the active ingredients in many products marketed as being “antibacterial” but this is still examining the internal microbiome in the intestines.

    I would say that triclosan would have an effect on the microbiome but not in the way we expect. If an individual grows up using antibacterial washes and soaps, the skin microbiome will be severely affected causing abnormal stimulation of the immune system. This causes the immune system to over react and target the skin. This is proposed as one of the contributing factors to eczema and some other skin conditions.

  4. Olivia Campbell says:

    It would be interesting to know if similar studies had been done on the effect of different soaps on the good and bad bacteria, particularly anti-bacterial soaps and body washes.

  5. gvarveri says:

    very interesting post indeed. It’s interesting that the most popular solution to preventing body odor is to essentially block a natural bodily function. I’ve always herd that aluminium base antiperspirants can be bad for you but I’ve never known why.

  6. wesleyw says:

    That’s a really interesting point!
    There currently is no conclusive or definitive evidence that the aluminium compounds in antiperspirants cause an increase in breast cancer rates.

    There is speculation that the aluminium compounds or parabens act as estrogen mimicking chemicals that promote breast cancer growth.
    But research in this area is conflicting and the methodologies in some of the positive experiments were slightly flawed.It may be possible that this is a rumour started by people who don’t truly understand the biology of cancer and can mistake correlation for causation.
    hope this website will clear most of your questions. 🙂

  7. samsing says:

    Very interesting post! I heard once that antiperspirants could cause cancer because they were blocking the natural secretion of our sweat glands, creating cysts that could then turn into cancerous cell proliferations. Is this true?

  8. wesleyw says:

    Thanks guys,
    Nick, there’s actually a ton of interesting research into our natural microbiome going on all over the world, its important in keeping us healthy by stimulating our immune system and stopping bad bacteria from colonising our mucosal surfaces (wet internal surfaces) too easily. Differences in natural bacteria have even been linked to asthma and irritable bowel diseases!
    Yea I do agree with you that it is a gross but that’s a small price to pay when you imagine if your smell repulsed everyone close to you.
    Sorry Nicole!
    The good thing is that after a couple days the your microbiome heads back to a normal composition so it doesn’t have permanent effects. 🙂

  9. Nicole Elliott says:

    Great Post! To think I only just bought a fancy “Clinical Protection” Anti-Perspirant. I went to check mine out as soon as I read your post and it is actually labelled as “Anti-Perspirant Deodorant” so I think they are trying to cover both the Anti-Perspirant and Deodorant markets with that. But sure enough Aluminium zirconium tetrachlorohydrex GLY is in the ingredients! Guess it’s back to the supermarket for me!

  10. njolly says:

    the thing that i find most amazing is the fact that people actually research this kind of thing!! great stuff, going to have to make the switch

    although the thought of having someone else’s armpit bacteria in my armpits is a bit disgusting… i don’t think too many people would be particularly keen on that option, but then again if people get desperate!!

  11. Lakvin says:

    Good post Wes!

  12. wesleyw says:

    Thanks for the question Sarah!
    A transplant could fail due to both reasons, the odourless bacteria being unsuitable for the recipient or the recipients natural bacteria recolonising too fast.

    My thoughts are that the smelly person’s bacteria composition has adapted to his armpit. So we would need odourless bacteria that can survive in a similar armpit environment in order for the transplant to be successful.
    Armpit environments are more likely to be similar in genetically similar people. That is why the good bacteria has the best chance of outcompeting the smelly ones even though it is a non invasive- non genetic procedure.

  13. Sarah Webber says:

    That’s amazing that the bacteria transplant is successful only if people are genetically related. Fascinating. I wonder what problems occur – does the transplanted bacteria simply fail to take hold? Or could it multiply TOO well??