Why Washed Shirts Still Smell of Body Odour

You switched to a natural deodorant. A week later you pull a clean t-shirt out of the wardrobe, walk to the station, and by the time you sit down there is a familiar smell coming off you. The obvious conclusion is that the new deodorant has failed.

Sometimes it has. But there is a second failure that produces exactly the same experience, and almost nothing written about natural deodorant mentions it: the odour is in the shirt, and it was there before you put the shirt on. A washed garment is not necessarily an odour-free garment, and the difference matters because one of those problems is solved by buying a different deodorant and the other is not.

This page separates the two. It is about odour you can smell in clean fabric — not about the white marks and yellow crusting deodorant can leave on a garment, which is a different failure with different causes.

The test that tells you which one failed

Before you buy anything else, establish which problem you have.

Take a garment you know has never been worn with the current problem — something new, or something cotton that has been sitting unworn at the back of a drawer. Wear it through a normal day with the same deodorant, applied the same way.

• If the odour turns up on schedule in the fresh garment too, the fabric was not carrying it — skip to “When it genuinely is the deodorant” below.
• If the fresh garment stays clean-smelling and your usual tops do not, the shirts are the variable, and a different deodorant will not fix them.

This is reasoning rather than a published protocol, and it is worth saying so: no study cited on this page tests that comparison. It changes one variable at a time, costs nothing, and settles a question people otherwise answer by buying a third deodorant.

What the research found about polyester and cotton

The best evidence that fabric — and specifically synthetic fabric — is a variable in body odour at all comes from Callewaert et al., “Microbial Odor Profile of Polyester and Cotton Clothes after a Fitness Session,” Applied and Environmental Microbiology 80(21):6611–6619 (2014), doi:10.1128/AEM.01422-14.

What the study did, in its own terms: t-shirts were collected from 26 healthy individuals after an intensive bicycle spinning session and incubated for 28 hours before analysis. A trained odour panel then assessed them, and the bacteria on the shirts were fingerprinted.

What it found:

• The polyester t-shirts smelled significantly less pleasant and more intense than the cotton t-shirts, on the panel’s hedonic value, intensity and qualitative odour characteristics.
• Micrococci were isolated from almost all the synthetic shirts and were detected almost solely on synthetic shirts by denaturing gradient gel electrophoresis fingerprinting. The paper implicates those micrococci in the malodour, supported by an in vitro growth experiment.

Now the scope, which is where this claim usually gets stretched into something the paper does not say. Twenty-six people, one intensive exercise session, one 28-hour incubation. That is evidence that fibre type shapes which bacteria grow and how the result smells. It is not a measurement of what happens to a shirt after it has been through a washing machine — the study is about worn shirts, not laundered ones. Anyone citing this paper as proof that washing fails to remove odour is citing it for something it did not test.

For the post-wash half of the problem, the honest sources are the people who make and test laundry products, and they are quoted as such below.

Where the smell hides in a “clean” shirt

Three published explanations, each with a named owner.

The fibre itself. Ariel UK’s guidance on washing sports clothes states that synthetic fabrics are “very prone to retaining odours, even when they’ve been through the wash,” and that “the stink-causing bacteria builds up on the inside of your workout gear.” (Ariel UK, “How to wash sports clothes”) That is a detergent manufacturer describing the problem its products address, so read it as such — but it is consistent with what Callewaert found about which bacteria colonise synthetics.

Fabric softener. Which? advises skipping it on activewear, on the grounds that it “traps odours and bacteria” and can block the moisture-wicking structure of the fabric (Which?, “7 handy tips for washing gym clothes,” Rebecca Jakeman, 22 January 2026). Ariel UK says the same thing from the other direction: the coating softener leaves “makes it harder for water and detergent to fully penetrate the fibres, leading to the build-up of odour-causing bacteria.”

Detergent dose, in both directions. Persil UK’s page on why washing smells puts it plainly: “Too much can mean that the detergent isn’t fully rinsed from the clothes and could create a bad odour, while too little could mean that your clothes aren’t being cleaned properly.” (Persil UK, “Why Does My Washing Smell? How to Get Smells Out of Clothes”) The same page notes that the machine is a candidate too: “Washing machines are not self-cleaning, and so they do require a bit of maintenance every now and then… mould can easily grow inside the washing machine as it is a dark, damp environment.”

None of that is our assertion. Each line belongs to whoever published it.

What published laundry guidance recommends

Method by method, with the source that recommends it. Nothing here is a household tip we invented, and where two sources differ, both are given.

Air the garment before it goes in the basket. Which? recommends airing gym clothes for a few hours before washing, because “without leaving space for sweat to evaporate, bacteria and smells can linger.” Persil UK’s activewear guidance says to “turn them inside out and hang them up to air as soon as you take them off to keep them from getting smelly or developing mildew” (Persil UK, “Stay Hygienic: How to Wash Gym Clothes, Swimwear, & Other Activewear”).

Turn it inside out for the wash. Which? gives the reason: it exposes the underarm area, where the bacteria are, directly to detergent and water. Persil UK’s activewear page says the same — “always wash sports clothes inside out too.”

Pre-soak the worst offenders, then rinse them properly. Which? suggests soaking particularly smelly items in white vinegar or baking soda mixed with water — with its own caveat attached, which should not be dropped: rinse thoroughly before washing, because white vinegar is acidic and can damage the machine, and because Which? notes baking soda can cause skin irritation. Persil UK’s version of the baking-soda soak is a cup of it in cold water, with the instruction to “test a small amount of your baking soda solution on a hidden area of the garment first to check there are no adverse effects.”

Use less detergent on synthetics, not more. Which? recommends “around half the amount of detergent you would for a standard load” for activewear, which lines up with Persil’s point above about detergent that does not rinse out.

Skip the fabric softener, per Which? and Ariel UK, as above.

Wash cool, and let the care label decide. Which? suggests 30 °C or cooler cycles for synthetic activewear. Persil UK’s activewear page says that for “modern-tech stretchy fabric, it is best to avoid using water temperatures higher than 30 °C, as this could damage the fabric,” and adds the rule that governs all of this: “always follow the garment care label when washing gym clothes.”

That last instruction is not a formality. Persil’s stain guidance points the other way — its deodorant-stain page says to “wash at the highest temperature the care label permits” — because removing a mark and protecting a stretchy synthetic are different jobs with different answers. Both versions defer to the label, and so does this page. If the care label allows it is a condition on every temperature named here, and no temperature above a garment’s label is recommended on this site.

Air-dry rather than tumble. Which? recommends a line or an airer over heat drying to protect elastane. Ariel UK puts it more strongly: “agitation and extreme heat will not only damage the fibres of your clothing, but will also amplify odours. Instead, just let your gym clothes air dry.”

Check the machine. Per Persil UK, above, a washing machine that smells makes everything in it smell.

What does not work

More deodorant. Nothing in the guidance above is addressed by applying more product, and over-application has a cost of its own — our own guide to how long deodorant lasts notes that excessive application causes residue build-up and clothing marks without improving effectiveness.

Masking it with fragrance. Every source quoted on this page recommends removing the bacteria and the residue. None of them recommends adding scent to fabric that already smells, and this page does not either. If you enjoy a strongly scented deodorant, that is a separate and perfectly good reason to choose one — see natural deodorant for fragrance lovers — but it is not a fix for odour held in a garment.

Buying a third deodorant before running the test above. If the shirts are the variable, the next product fails the same way, and by then the reader has concluded the whole category does not work.

When it genuinely is the deodorant

This is the honest half, and it matters as much as the rest.

If a freshly laundered garment that has never been part of the problem still smells by lunchtime, the fabric is not what failed. Three things are worth checking in that order:

1. How long you have been switched. The adjustment period after coming off an antiperspirant is real and is covered in switching to natural deodorant, which is also where the “it stopped working” troubleshooting lives.
2. Whether the formula suits you. Products differ in their active approach, and baking soda is the most common single point of difference — see is baking soda bad for skin and the best deodorants for sensitive skin.
3. What you are asking the product to do. A deodorant addresses odour. It does not stop or reduce sweat, and no amount of laundry advice changes that; deodorant versus antiperspirant sets out the difference. If wetness rather than smell is the problem, the fabric question above is not your question.

From there, the product reviews are filtered by skin sensitivity and scent family.

FAQ

Does natural deodorant make clothes smell worse than antiperspirant did?

No source found for this page establishes that comparison, and this page will not invent it. Callewaert 2014 compared fabrics, not deodorants — it did not test what participants had on their skin as a variable. The laundry guidance quoted above is written about sweat and bacteria in general and says nothing about deodorant type. If you switched and noticed fabric odour at the same time, the test at the top of this page is the way to find out whether the two are actually connected, rather than assuming they are.

Is this the same as deodorant stains?

No. White marks and yellow crusting on a garment are a visible-residue problem with its own causes and its own removal methods. This page is about odour in fabric that looks clean. The two can happen to the same shirt and neither explains the other.

Will a very hot wash fix it?

Not a question this page will answer with a number. The two sources quoted above that address synthetic activewear specifically both point at 30 °C or cooler and both defer to the garment’s care label, and washing above the label risks the garment. What the label permits is the ceiling, whatever anyone on the internet recommends.

Does this mean cotton is better?

Callewaert 2014 found the polyester shirts smelled significantly less pleasant and more intense than the cotton ones under the conditions it tested, and found micrococci almost solely on the synthetics. That is what the study supports. Our switching guide already notes that natural fibres allow air circulation. Whether you should replace a wardrobe of technical fabric on the strength of one 26-person study is a decision the study does not make for you.

Do I have to throw the shirt out?

Nothing quoted here says so. The published guidance above is about washing method — airing, soaking, dose, softener, temperature, drying and the machine itself — and it is worth working through before deciding a garment is finished.

The short version

• A clean shirt that smells when you warm up is a different failure from a deodorant that is not working, and the two are routinely confused.
• Callewaert et al. 2014 found polyester shirts smelled significantly less pleasant and more intense than cotton ones after an intensive spinning session and 28 hours’ incubation, with micrococci almost solely on the synthetics — in 26 people, on worn shirts, not laundered ones.
• Which?, Persil UK and Ariel UK all recommend airing before washing, turning garments inside out, and skipping fabric softener on synthetics.
• Which? recommends about half the usual detergent for activewear; Persil notes that both too much and too little detergent can leave clothes smelling.
• Both activewear sources point at 30 °C or cooler for synthetics, and every one of them defers to the garment care label. So does this page.
• Change one variable — the shirt — before you change the deodorant.