woman sniffing her smelly armpit and checking for stinky body odor

Ever wonder what causes body odor and why some people have stinky armpits and others don’t? Most people assume it is sweat. Perspiration per se is not smelly, but it is essential to the production of armpit aroma.

Scientists at the University of York in the UK recently presented the fascinating results of their research into underarm odor at the annual meetings of the Society of General Microbiology (March 30, 2015). They discovered that it all depends upon the bugs residing in your axillae (the scientific name for armpits).


The Biochemistry of BO

The intrepid investigators found over 150 different species of bacteria had set up housekeeping in the armpits of their subjects. After isolating all these germs, the researchers discovered that some feast on our sweat and then churn out compounds called thioalcohols. These are the bad actors behind body odor. Because they are volatile they don’t stay put. As thioalcohols evaporate, they escape into the surrounding atmosphere.

Some liken the smell to sulfur (a rotten egg odor), while others describe it as bad meat or nasty onions. The smell is so powerful it can be detected at 1 part per trillion. In other words, it doesn’t take much to make people in the vicinity turn up their noses in disgust.

The particular bacteria responsible for making thioalcohols belong in the staph family. Specifically, Staphylococcus hominis seems to be the worst offender. S. hominis and two staph cousins produce special enzymes that go to work on molecules in sweat and then churn out thioalcohols.

The Unilever Connection

It may come as no surprise that the Unilever personal care product company helped fund this research. These are the folks who bring you Dove, Lifebuoy soap and bodywash, Pond’s skin cream, Clear shampoo and Vaseline. They may be trying to develop a high-tech deodorant that prevents the formation of thioalcohols.

The Problem with Existing Antiperspirants and Deodorants


The FDA classifies antiperspirants as drugs. That’s because the products affect the biology of the skin. The agency requires companies to include substantial amounts of aluminum (aluminum chlorohydrate, aluminum chloride, aluminum-zirconium compounds, etc.) if they want to label a product as an antiperspirant. Aluminum forms a plug over the sweat glands, causes swelling and temporarily reduces perspiration.

The less sweat there is, the fewer nutrients there are for S. hominis to feast on. That means fewer thioalcohols will be produced and less body odor will be detectable.


Deodorants are considered cosmetics. They do not stop sweating and generally work by masking body odor with a fragrance. This harkens back to the middle ages when royalty rarely bathed. Instead, they poured on the perfume in an effort to cover over unpleasant smells.

We are not overly impressed with this approach. It seems a bit like putting a hanging deodorant tree on the rear view mirror to try and overcome the unpleasant odor in a smoker’s car. As far as we’re concerned, it never really masks the smell of smoke. Someone with bad BO probably cannot overcome it with a perfumed deodorant.

Home Remedies:

It’s hardly any wonder that People’s Pharmacy fans find neither approach (aluminum-containing antiperspirants or deodorants) particularly appealing. For one thing, aluminum exposure has been linked with brain inflammation and Alzheimer’s disease. Concerns have also been raised about aluminum and cancer.

That’s why visitors to this website and readers of our syndicated newspaper column have come up with all sorts of intriguing alternate solutions to body odor. Here are just a few examples:

M.H. offers this:

“Mix equal parts of baking soda with cornstarch then add enough water to form a paste. Every morning wet your fingers and rub it across the hardened mixture; then apply it to your under arms. You will be odor free the whole day. It won’t stain your clothing.”

J.T. suggests:

“I use 70-90% rubbing alcohol – poke a SMALL hole in the top seal and squeeze a 1/4-1/2 teaspoon in a palm and rub in in the underarm area – kills the bacteria that grow in the sweat. It evaporates and leaves nothing. Cheap also and best of all – no awful perfume scent.”

R.C.M says:

“Ever since I underwent chemotherapy and lost all of the hair in my arm pits I stopped using deodorant and now I simply use witch hazel. It works great for me.”

People have used lime juice, lemon juice, white vinegar, old-fashioned amber-colored Listerine and house brand milk of magnesia on their underarms. We suspect that all these approaches impact the growth of bacteria, especially those that cause the formation of those nasty thioalcohols. Here is a link to more in-depth stories about home remedies for body odor.

The trouble with all these home remedies is that they are not very easy to apply. Splashing or spritzing your underarms with rubbing alcohol, lemon juice, vinegar or milk of magnesia can be messy. And over-the-counter milk of magnesia contains sodium hypochlorite (bleach) as a preservative. We are not crazy about putting bleach, even in small quantities, on our underarms.

The People’s Pharmacy Aluminum-Free MoM (Milk of Magnesia) Roll-On

Several years after we heard that milk of magnesia was especially helpful against body odor we decided to try and come up with an easy applicator. We worked hard to eliminate the aluminum and the bleach and find a roll-on system that would make MoM easy to apply.

Here is a video to explain more about this product.

Eventually our brilliant natural products chemist created a terrific formulation. He helped us develop an Aluminum-Free Women’s MoM Roll-On deodorant with a gentle floral fragrance. Some people love the smell so much they have encouraged us to turn it into a perfume and a line of body care products. So far we have resisted.

Not everyone likes the fragrance, however. For those who prefer an unscented deodorant (proving that it is not a cover-up), we developed The People’s Pharmacy Aluminum-Free MoM. It was out of stock for several weeks, but we now have a great new supply. Please do NOT take our word on the popularity of these two products. When you go to the store, take a few minutes to read the reviews for Women’s MoM and unscented Aluminum-Free MoM. By the way, there are at least 5 pages of reviews and our overall rating is 4.6 stars out of a possible 5 for our unscented MoM deodorant.

We don’t know how, or even if, our Aluminum-Free MoM Roll-On Deodorant kills Staphylococcus hominis or makes the environment inhospitable for these bacteria to thrive. All we know is that we have a lot of very happy customers. Why not give MoM a try? If you are not happy, we will refund your money. Here’s a link to our body care products should you wish to find out for yourself.

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  1. Libby

    I had this problem for years, try every antiperspirant & deodorants in the store and my problem persisted, even just out of the shower my smell was horrible, onion smell, I found TOM’S deodorant aluminum free, it’s been like 3 years and still works for me, I hope this work for sombody else.

  2. Stacie

    MoM did absolutely nothing for me. I went back to Secret. Looked for a natural deodorant and found a recipe that was 1 cup coconut oil mixed with 1/4 cup baking soda and 1/4 cup cornstarch. No odor, but 2 days into use, I have developed a burning rash on my armpits. So I am back to where I was with Secret.

  3. Noah
    Chapel Hill,NC

    I have found that putting alcohol in a spray bottle allows for quick, easy and clean application.

  4. JBG

    “…over-the-counter milk of magnesia contains sodium hypochlorite (bleach) as a preservative. We are not crazy about putting bleach, even in small quantities, on our underarms.”

    This is hokey. Milk of magnesia is sold as a laxative. The specified dose is up to FOUR TABLESPOONS — a quarter of a cup — taken internally!

  5. Mary Jane

    What we eat makes a difference in how we smell. I notice a (positive) difference in underarm perspiration when I stopped eating sugar. Others report a similar experience when they eliminated meat from their diets.

    • Moodymoose

      I’m not wiling to drop certain foods from my diet. The healthy things make you smell the most anyway. LOL

  6. Kyizom
    United States

    What about stone deodorant crystal?

    • Mary
      United States

      People’s Pharmacy has said in past posts on underarm odor that most of the crystal deodorants contain alum as an ingredient. Alum is a form of aluminum. If you want to avoid aluminum, then avoid any product that has any variant of the word in its ingredient list.

  7. Donnie

    I’m allergic to sulfites, and also became allergic to onions and garlic. Some foods high in natural sulfer cause me to reek and I exude the odor. Broccoli and other similar foods are major offenders. Eggs and black-eyed peas not so much. Red meat can cause odors, too. I avoid the ones that cause the most problems. I wash my underarms with soap with a bit of epsom salts in the water. If I need more to kill an odor, I put vodka on a cotton ball and rub under my arms. That works very well of me.

  8. Lesley
    St. Louis

    I tried the MOM and unfortunately the resulting odor was indescribable. I guess my body makeup is not compatible. Had to go back to usual deodorant.

    • ebm

      Lesley, MOM does not last long enough for me either. I now swear by a 50:50 solution of water and WHITE vinegar, apple cider vinegar gets sticky. No more BO and no smelly clothes!! Purell type hand cleaner works well also, but does not last as long for me.

  9. Kat

    MoM is all well and good for stopping smells, but I sweat a great deal, especially in Florida. I need something to stop the sweat or I can’t go out in public from about May through October. I understand the chemistry and concerns with using antiperspirants, but is there anything else (something safer) that would help me with this problem?

  10. Michael
    Madison, WI

    I have been using 70% alcohol under my arms for years. I put the alcohol in a small squirt bottle and squirt it onto my palms, then apply underarms – It kills the bacteria and I am free of smell for days. Cheap and very effective.

  11. Kathy

    Can you advise on alternatives to aluminum for an anti-perspirant?

  12. Pam

    Does your deodorant stop perspiration? Did not see that in your description.

  13. C

    I like 3 things about MoM: 1. It works. 2. It’s a bacterial growth inhibitor. It doesn’t give me a rash like antiperspirant nor does it kill the bacteria and make room for worse bacteria. 3. It’s ingredients are not absorbed through the skin, like the triclosan some deodorants have. Triclosan is nasty: it’s not something you want to absorb.

    • Mary

      I would bet that anything (everything?) put on our underarms might be absorbed into the skin. So please use caution.

      Think about magnesium oils designed for external use.

  14. Red

    I really love and recommend MoM to anyone who wants their deodorant to be aluminum free! It really does work on the odor–just as effectively as store-brand anti-perspirants! If you can’t stand sweating and have to resort to anti-perspirants in the heat of summer sun, at least that’s about 10 months of the year, you can use MoM.

  15. Marian
    United States

    Easy & cheap to buy, simple to appy, hand sanitizer (alcohol in gel) does the trick.

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