How does natural deodorant work?

June 29, 2025

There are a lot of natural deodorant brands out there and it seems like we're all knocking elbows trying to make a unique impression and claim our piece of the deodorant market. But how do natural deodorants work differently from conventional deodorant and is there really any difference between all these brands? I'll take a look at the active ingredients that you're most likely to find in a natural deodorant and break down what it actually does. Plus, will conventional deodorant actually destroy your health and give you cancer?? (Spoiler alert, it's unlikely. But there are other reasons to use natural deodorant!)

What is natural deodorant?

The first snag we hit is that there is no one definition or ingredient that makes deodorant natural. It's pretty widely agreed that there are things that should NOT be found in natural deodorant. Aluminum (more about that here), parabens, and synthetic fragrances usually top most people's lists. Though to counter that, Tom's of Maine actually makes an aluminum based antiperspirant that otherwise ticks all the natural boxes. So opinions certainly differ.

For the purposes of this article, I'm going to look at deodorants that don't include aluminum salts for sweat control (so no antiperspirants qualify). That still leaves a fairly wide umbrella and while the goal of all natural deodorants is the same (stop stinky pits!), there are many odor control methods out there. First, lets do a quick look at why pits are so stinky in the first place.

Biology of a stinky armpit

If you've ever looked at skin care products, you've probably heard the term "pH balanced." The pH scale is a 1 to 14 scale that indicates how acidic or alkaline something it, with 1 being very acidic, 7 being neutral and 14 being very alkaline. Healthy skin usually has a pH of around 5.5, which is slightly acidic. Areas like the underarms that are damp and not as exposed to air are a little less acidic, around 6. Cleverly, the bacteria that live in your armpits are very good at reproducing themselves at this pH, especially when bathed in sweat. As the bacteria reproduce, they create stinky byproducts and pretty soon you have a stinky armpit.

The type of sweat glands in your armpits also plays a big part. Our bodies have simple eccrine sweat glands almost everywhere we have skin. These sweat glands produce a very watery sweat which helps us stay cool in the heat and these are functional even in infants and children. Our armpits and groin, however, are also home to apocrine sweat glands, which only fire up once puberty begins.

The sweat from apocrine glands contains lots of protein rich bacteria food, so while it is odorless when it initially appears, it soon feeds your resident armpit bacteria and that growing population gets stinky fast! The apocrine glands are also responsible for stress sweat. [1]

How to stop the stink

The real problem in coming up with an effective natural deodorant is that smelling nice after sweating isn't natural at all. The first deodorant was only patented in 1888 (but apparently wasn't very effective) while the first antiperspirant was patented in 1903 (and it worked, though it stained and occasionally ate through clothes, not to mention irritating arm pits, so there were improvements to be made). That's a whole lot of human history without deodorant and in fact, one of the first challenges that deodorant makers had to overcome was convincing people that they needed to wear deodorant! (Check out the full Smithsonian article about the history of deodorant and advertising here! [2])

But let's shelve the debate about deodorant in modern culture for now and assume that you want to use deodorant. To stop your pits from stinking, we have to either deprive the bacteria of food (e.g. block sweat glands with aluminum, which we've decided we're not doing), change the pH of the armpit to make it inhospitable to bacteria, kill the bacteria outright, or possibly encourage the proliferation of non-smelly bacteria to out compete the stinkers.

Baking Soda

From my informal survey of natural deodorant brands (which really messed up my ad algorithm by the way, so you're welcome :), baking soda is the most popular active ingredient in natural deodorant. I can see the appeal. It's an ingredient almost everybody recognizes from their kitchen cupboards and, even better, it actually works pretty well.

If you remember the pH scale from earlier, baking soda is very high on the scale and thus very alkaline. It also dissolves very readily in water or sweat. This means that when you apply a baking soda deodorant, the baking soda starts dissolving as soon as you start sweating and makes you armpit very alkaline, instead of its natural state of slightly acidic.

In some ways, this is good. The bacteria that make your pits stinky do NOT like an alkaline environment, so you stay smelling fresh and clean as long as the baking soda lasts. This leads us to the downsides. First of all, that big flush of alkalinity can be pretty irritating to the skin, resulting in breakouts and rashes. Also, baking soda dissolves so readily in water (e.g. your sweat) that if you're doing a lot of sweating, it's possible to dilute it to the point where it's no longer effective.

Magnesium Hydroxide

So, what if we could slow down that big flush of alkalinity, maybe with a mineral that less soluble in water than baking soda...? Oh, look, magnesium hydroxide! This is my personal favorite, which is why I use it in Farmer Pits natural deodorant. Magnesium hydroxide works by raising alkalinity, just like baking soda, but the difference is that it only dissolves very slowly in water. This means magnesium hydroxide provides alkalinity in a "slow release" format. With no big flush of alkalinity when you start sweating, it is far less irritating to the skin and with its reduced solubility in water, it is much longer lasting.

Long Term Issue with Alkalinity

Unfortunately, ingredients like baking soda and magnesium hydroxide have not been well studied as deodorants. We know they are safe because both ingredients have been around for so long in various products (magnesium hydroxide is the main ingredient in milk of magnesia) that we've learned about most potential issues through collective experience. However, that's not the same as studying something scientifically to learn more about using it for a specific purpose.

For example, there's some evidence that long term use of alkaline deodorants can eventually encourage the growth of bacteria that both thrive in alkalinity and are very stinky... Here's the study [3] that found some extra smelly strains of bacteria that can develop after playing with armpit pH for a while.

This doesn't sound great but it is not a study that has been widely replicated at this time, so it's probably a bit early to be tossing out magnesium hydroxide deodorants (or even baking soda ones). The upside is that it may explain why some people find that natural deodorant suddenly stops working for them or never works for them in the first place. For a lot of people though, magnesium works really well and for anyone committed to natural deodorant, there are not many other alternatives that still fall under the "natural" umbrella.

Starches

This category covers ingredients like cornstarch, arrowroot powder, tapioca starch and other absorbent powders. These ingredients are mainly there to help soak up sweat, so your pits feel drier. All of these starches have their limit though, so if you're very active you'll eventually sweat enough to overload their absorptive ability. If you see a natural deodorant that is only composed of waxes and oils plus some form of starch and fragrance, it's likely a fairly mild deodorant and may not work for more active or sweaty people.

Alpha Hydroxy Acids (AHAs)

A newer option that has been growing in popularity is using skin safe, exfoliating acids to reduce armpit pH, instead of raising it. Some examples of these AHAs are lactic acid, mandelic acid and citric acid. [A fairly non-scientific look at AHA deodorants 4]

There are a few issues with this method. Like baking soda, these acids are prone to being diluted by sweat so much that they aren't effective anymore. It also seems like AHAs are difficult to incorporate into a traditional stick deodorant. You will notice that most AHA deodorant brands offer sprays, creams and roll ons rather than solid sticks. I'm not enough of a chemist to tell you why but I imagine there's something about AHAs that makes them either less stable or less effective in solid form

For a small scale maker such as myself, AHA deodorant recipes and ingredients are nearly impossible to find online. I think this is mostly due to this being a relatively new deodorant method and perhaps given a few years we'll see AHA based DIY recipes. Currently, I would need to either purchase a formulation or hire a chemist to make one for me, both of which are pretty expensive options for a small company, especially when the effectiveness isn't a sure thing. There is a pretty big brand name that makes a solid stick AHA deodorant but I'm pretty sure they have a team of chemists on staff who probably aren't spilling the beans about how they did it!

And of course the main issue for me is that if AHAs aren't happy in solid stick form, then I can't really include grass-fed tallow as a star ingredient! For now, I think I'll leave this method to the deodorant specialists.

Zinc Ricinoleate

Here's another rising star in the deodorant world: zinc ricinoleate. This compound is derived from castor beans but does not contain any toxic ricin after processing. It is a waxy oil that absorbs and neutralizes strong odors at the source, without relying on any changes to armpit pH to do it. While it doesn't seem to perform well enough to be a deodorant all on its own, it can lend a helping hand to alkaline based recipes.

This is why you will soon be seeing zinc ricinoleate included in all Farmer Pits natural deodorants! As I make new batches of various scents, I'll be including this new ingredient, hopefully making Farmer Pits more effective for all of you who rely on it! You'll know a particular scent has been updated by the new look of the label.

Essential Oils

Many essential oils are anti-microbial [5] and thus help deodorize as well as mask odor. Different oils have different levels of effectiveness, however. This is why I'll be adjusting the Farmer Pits scent line up to make sure that all scents contain at least one essential oil with good anti-microbial activity. Essential oil blends often can have a more complex, pleasant smell than a single oil alone, so hopefully you will enjoy the smell better too!

Not all natural deodorants stick strictly to essential oils though. Anything that is simply listed as "fragrance" or "parfum" is probably at least partly synthetic fragrance. The benefit of this is that synthetic fragrances tend to stick around longer, which means even if the active ingredient in a deodorant has stopped working, the fragrance may still be able to mask any pit stink. I like people to know what they're getting in my deodorant though, so I'll be sticking to essential oils!

Probiotics and Prebiotics

There's not a lot for me to write about these. Not much research has been done and no deodorant uses pre- and probiotics alone, they always seem to be used in conjunction with other odor stoppers. As far as I can tell, jamming some lactobacillus or inulin into an existing deodorant recipe is probably just feel good flim-flam, though I'm open to looking at any research on the subject!

The one product in this category that seems to have some scientific clout behind it is a body spray made with ammonia-oxidizing-bacteria. This is a whole other world of skin care that I am definitely under qualified to talk about, so I'll just drop the link here and move on [6].

Silver

Did you know that silver has anti-microbial effects? These effects have been harnessed by a few deodorant makers with apparent success. The science is still not quite there for silver as a deodorant (here's a thorough overview of silver and some other newer natural deodorant ingredients [7]), as it's been difficult to prove if silver works specifically against the kind of bacteria that cause armpit odor. However it does seem to work for some people and since silver as an element is fairly inert, it seems to not cause rashes or irritation.

Some silver based deodorants use silver nanoparticles, since smaller particles with more surface area allows for a smaller amount of silver to be used without losing effectiveness. While some amount of silver nanoparticle usage seems to be safe, the exact limits have yet to be established [8]. Nanoparticles are smaller than microparticles and can cross the skin barrier, the effects of which are not thoroughly understood. By contrast, silver microparticles are much bigger and are unable to cross the skin barrier.

Something else to consider with silver is potential environmental effects from silver in wastewater. While the number of people using silver in deodorant and other cosmetics is quite low currently, it's important to establish safe environmental limits for novel substances like silver nanoparticles. A study specifically looking at sliver nano particles in wastewater was done in South Africa [9] which found negative effects on both ecosystems and the beneficial bacteria in sewage treatment plants.

Another factor that requires further study is the potential for bacteria building up a resistance to silver's antimicrobial effects. No proof of this has been found but the European Commision's summary of silver nanoparticle safety [10] recommended looking into this further.

Phew! That was a lot of studies! I think that just goes to show that some caution around the use of silver, especially nanoparticles, is warranted. While it doesn't seem to pose any major dangers to human health, silver nanoparticles can be very disruptive to ecosystems, especially aquatic ones, in high enough concentrations, and nanoparticles are new enough that they're not something we fully understand. By contrast, the importance of monitoring pH in wastewater is very well studied and understood [11] and is well regulated in much of the world. So ingredients like baking soda and magnesium hydroxide don't have surprise environmental effects in store. (That my last source citation, I promise!)

Sooo... which deodorant should I use??

Well, I certainly recommend giving Farmer Pits a try, especially if baking soda deodorants have caused you irritation in the past. Magnesium hydroxide is much gentler on the skin than baking soda and our tallow and coconut oil base is highly moisturizing! If you find you are sensitive to synthetic fragrances, our deodorant is scented only with essential oils.

What I'm not going to do though, is give you the scare tactics about the horrors of aluminum or synthetic fragrances. Natural deodorants are great if they work for you. There are individual differences in body chemistry due to hormones, skin microbiome and other factors that are not completely understood. If you're a super-sweater (hyperhidrosis is no joke) or find that natural deodorant leaves you stinky no matter what brand you try, it may be worth looking at "natural-ish" options from the bigger brands. They have the advantage not only of on staff chemists but they have the budget to do large scale product tests, so they can make sure their products work for a wide range of people.

Am I hampering my own sales here?? Possibly. But if I learned one thing from my survey of natural deodorant brands, it's that there is SO MUCH inaccurate marketing out there. Almost every time I'm drawn in by an ad that seems to advertise a new and exciting natural deodorant formula it turns out to be.... yet another baking soda deodorant! Or possibly a magnesium hydroxide deodorant that has a more robust marketing budget than I do!

Hopefully this will help you look past the marketing and find ingredients that work for you. In the case of Farmer Pits, you're getting magnesium hydroxide, zinc ricinoleate (this one only in the updated formula that I'm rolling out across the various scents in the coming months) and essential oils.

On the whole, the best way to categorize natural deodorants is to look at their active ingredients. Anything that looks like a fat, wax or oil is just a carrier (plus more processed carriers like capric triglycerides). Any starches are just there to absorb some sweat. Any fragrances not specifically defined as essential oils or as natural are probably synthetic, though synthetic fragrances are well tolerated by a lot of people (and some people are sensitive to essential oils!).

Looking for a gentle and effective natural deodorant? Give Farmer Pits a try!