Deodorant is not medically necessary. Sweating is a normal bodily function, and underarm odor, while socially unwelcome, poses no health risk. Whether you need deodorant depends on your body chemistry, your genetics, your clothing choices, and how much odor bothers you or the people around you. Some people genuinely produce very little underarm smell, while others generate noticeable odor within hours of showering. Understanding why that variation exists can help you decide what, if anything, you actually need to use.
Why Underarms Smell in the First Place
Fresh sweat is essentially odorless. The smell comes from bacteria living on your skin that feed on the proteins, fats, sugars, and ammonia in sweat produced by the glands concentrated in your armpits, groin, and a few other areas. These glands produce a thicker, lipid-rich sweat compared to the watery sweat that cools you down during exercise. When bacteria break down those fatty compounds, the byproducts are what you recognize as body odor.
This means odor is really a bacterial problem, not a sweat problem. Anything that reduces the bacteria on your skin or limits their food supply will reduce smell. That’s exactly what deodorants and antiperspirants do, through two different mechanisms.
Deodorant vs. Antiperspirant
These terms get used interchangeably, but they work in completely different ways. Deodorants target the bacteria that cause odor, using antimicrobial agents to slow bacterial growth. Many also contain fragrances that mask whatever odor does develop. Antiperspirants take a different approach: they use aluminum-based compounds that form a temporary gel plug in your sweat pores, physically blocking sweat from reaching the skin surface. Less sweat means less food for bacteria, which means less odor. Antiperspirants also keep your underarms visibly dry, which is why people who are bothered by sweat stains tend to prefer them.
Many products on the shelf are combination formulas that do both, so check the label if the distinction matters to you.
Some People Genetically Don’t Need It
One of the most striking findings in body odor research involves a gene called ABCC11. A specific variant of this gene dramatically reduces the precursor compounds in underarm sweat that bacteria feed on. People with this variant produce very little underarm odor and also have dry, white earwax instead of the wet, yellowish type.
This variant is overwhelmingly common in East Asian populations, present in 80 to 95 percent of Japanese, Korean, and Chinese individuals. It’s extremely rare among people of European and African descent, showing up in fewer than 3 percent. If you have dry, flaky earwax, there’s a good chance you carry this gene variant and may produce little to no underarm odor, making deodorant genuinely unnecessary for you. Studies have found that many people with this genetic profile use deodorant anyway out of social habit rather than biological need.
What Deodorant Does to Your Skin Bacteria
Regular product use meaningfully changes the bacterial community living in your armpits, and not always in predictable ways. A study from North Carolina State University found that people who regularly used deodorant actually had fewer species of bacteria in their armpits than people who used nothing at all. Antiperspirant users, on the other hand, had more diverse bacterial communities after stopping use for several days than either group.
The practical takeaway: when you stop using a product you’ve relied on for years, your armpit microbiome needs time to rebalance. This is why many people experience a “transition period” of increased odor when they quit deodorant or switch to a natural product. That adjustment doesn’t last forever, but it can take a couple of weeks.
Alternatives That Actually Work
If you want to reduce odor without a traditional deodorant stick, you have options that target the same underlying cause: bacteria.
A benzoyl peroxide wash, the same kind sold for acne, can be used in the shower on your underarms. Dermatologists at Baylor College of Medicine confirm it works by killing odor-causing bacteria on the skin surface. With consistent use, it reduces the bacterial population enough to meaningfully cut body odor. It won’t stop you from sweating, but if odor rather than wetness is your concern, it’s a legitimate alternative.
Your clothing also plays a larger role than most people realize. Research published in Applied and Environmental Microbiology found that polyester and nylon fabrics selectively encourage the growth of bacteria most associated with strong odor. After a fitness session, polyester shirts harbored dramatically more of these bacteria than cotton shirts. Cotton still allowed some bacterial growth, but it didn’t favor the worst odor-producing species. If you’re trying to get by without deodorant, wearing natural fibers (especially cotton) can make a noticeable difference.
Natural Deodorant Ingredients
Natural deodorants typically rely on one of two active ingredients. Baking soda (sodium bicarbonate) is highly alkaline and neutralizes bacteria aggressively. It works well for heavy sweaters and active people, but its high pH can irritate sensitive skin, causing redness, burning, or a rash in the armpit area. Magnesium hydroxide is a gentler alternative that neutralizes odor-causing bacteria through a less aggressive chemical process. It’s nearly undetectable on the skin and is better tolerated across skin types, though both ingredients provide comparable odor control when formulated at effective concentrations.
If you’ve tried a natural deodorant with baking soda and developed irritation, switching to a magnesium-based formula is worth trying before concluding that natural options don’t work for you.
Is Aluminum in Antiperspirant Safe?
The concern that aluminum in antiperspirants causes breast cancer or Alzheimer’s disease has circulated for decades, but the medical evidence doesn’t support it. A comprehensive 2014 review in Critical Reviews in Toxicology found no correlation between aluminum-containing antiperspirants and increased cancer risk. The basic reason: your skin is an effective barrier, and the amount of aluminum that could theoretically absorb from a daily application is far too small to reach toxic concentrations in the bloodstream. Dermatologists continue to recommend aluminum-based antiperspirants to patients without reservation.
Who Can Skip It and Who Probably Shouldn’t
You can comfortably skip deodorant if you carry the ABCC11 gene variant (check your earwax type as a rough indicator), if you shower daily and find you don’t develop noticeable odor, or if you work in a setting where mild body scent isn’t a concern. Wearing cotton or other natural fibers, showering after exercise, and occasionally using an antibacterial wash can bridge the gap for people with moderate odor who prefer not to use a daily product.
If you produce noticeable odor within a few hours of showering, work in close quarters with other people, or are bothered by sweat stains, some form of underarm product will make your life easier. That could be a conventional antiperspirant, a natural deodorant, or even a benzoyl peroxide wash in the shower. The “right” choice is whichever one matches your body chemistry, your skin sensitivity, and how much you care about the issue in the first place.