A garment can retain an odour after washing because its fibres, odour compounds and microbial communities all play a part in the problem. Drying matters too. A persistent smell is therefore not enough to conclude that your deodorant is not working. Start by noticing when it appears, then check the fabric’s care instructions, your programme, detergent dose and how the laundry dries.
Does the smell come from your skin or the garment?
Sweating and smelling bad do not describe exactly the same thing. A worn fabric receives secretions, microbes from the skin and odour compounds. It becomes an environment in its own right: its smell does not only reflect that of the armpit. The work of Díez López and colleagues examines this journey between skin, clothing, washing and drying.
To guide your trials, ask whether the smell is already on the dry garment before you wear it, or whether it returns during activity. Compare it with another top too. This simple observation helps you choose what to adjust; it does not identify a bacterium at home.
Why do some fabrics smell more after exercise?
In a study published in 2014, Chris Callewaert and colleagues analysed the T-shirts of 26 people after an intensive cycling session, followed by 28 hours of incubation. The panel rated the smell of polyester T-shirts as more intense and less pleasant than that of cotton T-shirts. Bacterial communities also differed between fabrics.
This experiment shows that the material deserves consideration. It did not test washing: it therefore does not prove that a particular programme fails on polyester. It also does not mean that every synthetic garment will smell bad, or that cotton will always stay odour-free.
What do we know about odours that return after washing?
A 2025 study followed synthetic T-shirts through wearing, washing and drying in 31 participants selected for their odour profile. Washing reduced the odour compounds studied, but the microbial communities changed, and odours reappeared under the damp drying conditions tested.
This was a specific protocol; it does not explain every problem with a home washing machine. The study, funded by Givaudan, mainly reminds us that drying is part of the problem. Smelling the laundry as it leaves the machine does not necessarily tell you what it will smell like once dry.
Which care symbols should you check?
Read the label before changing the temperature. According to GINETEX, the number in the washtub indicates a maximum temperature. Bars under the tub call for gentler mechanical action. The triangle concerns bleaching; the square, drying.
The material alone is not enough to choose a treatment: colours, finishes and the garment’s construction also matter. A sports T-shirt and a delicate jumper do not automatically need the same solution. Follow restrictions on tumble drying and bleaching products too. A 30 °C label is not a guarantee that all microbes or odours will be removed.
Which steps should you try, and in what order?
GINETEX’s Clevercare advice recommends keeping dirty laundry in a dry, ventilated place, adjusting the load and following the detergent’s instructions. For your next trial:
- If the garment is damp after exercise, wash it promptly or let it dry before putting it aside for later washing.
- Choose a programme compatible with the label and the level of soiling; a short cycle is not an automatic answer to a persistent odour.
- Follow the load limit for that programme so clothes have room to move.
- Dose detergent according to its packaging: adding more does not guarantee a better result.
Then take the laundry out and hang it up as soon as the cycle ends, as Clevercare recommends. Wait until it is dry before putting it away. If several items come out with the same smell, also consult your machine’s maintenance instructions.
Change one thing at a time and note the result on the same garment. You can then keep what helps without multiplying treatments or going beyond the fabric’s care instructions. Deodorant remains a separate choice, related to skin and body odour: our deodorant and antiperspirant guide explains their functions.
Frequently asked questions
Should you always wash hotter to remove an odour?
No. Follow the maximum temperature on the label and also check the programme, dosing and drying. No single temperature suits all garments.
Does cotton never smell bad?
No. The 2014 study reports a difference under its experimental conditions, not a guarantee for every cotton item.
Can adding more deodorant clean a T-shirt?
No. Deodorant is used on the skin according to its instructions. If the smell is already present on the washed fabric, examine its care routine.
Sources and further reading
- Callewaert et al., 2014 — Microbial odor profile of polyester and cotton clothes after a fitness session
- Díez López et al., 2025 — Unravelling the hidden side of laundry: malodour, microbiome and pathogenome
- GINETEX — Textile care symbols
- Clevercare / GINETEX — Washing advice
- Clevercare / GINETEX — Everyday laundry care