Turn a training top inside out and the label will tell you what it is made of: lyocell, cotton, polyamide, elastane. It will not tell you what was added to the fabric afterwards. If the garment promises to stay fresh, something was, and that something rarely gets a line on the label.
The Financial Times put the wider question in a headline: "How toxic is your sportswear?" We think odour control is one of the places where it deserves a specific answer.
What "odour-resistant" usually means
Sweat itself has almost no smell. The odour comes from bacteria breaking it down on the fabric. Most odour-resistant garments are treated with something that stops those bacteria, and for years one of the most common choices in sportswear has been silver.
What a Swedish study found about silver
In October 2018, Svenskt Vatten, the industry body for Sweden's water utilities, published a report called Silverläckan ("The silver leak"). Laboratory tests measured how much silver was left in silver-treated sports garments after ten machine washes.
Between 31 and 90 per cent of the silver had washed out. One pair of tights kept only a tenth of what it started with.
Two things follow from that. The silver ends up in wastewater, which is why the water utilities commissioned the study in the first place. And a treatment that has left the fabric is no longer doing its job, so the garment you paid for is not the garment you have after a few months.
These results describe the garments that were tested. They are not a wash-out rate for every silver treatment on the market. They are a good reason to ask what happens to a treatment in the wash, and not only how it performs on day one.
What APRÍ uses instead
Every APRÍ garment has an odour treatment, and we use two. Both are plant-based, and neither contains silver, zinc or any other heavy metal.
APRÍshield™, powered by NordShield
NordShield is made from wood extractives and is biodegradable. It forms an ultrathin, invisible layer on the fibres that captures and neutralises odour. It is not a biocide, and it is exempt from the EU Biocidal Products Regulation for that reason.
We use it on all our lyocell pieces (t-shirts, polo and cropped tee) and all our cotton pieces (hoodies, crew necks, box tees and sweat shorts). In independent testing it retains 99.9% of its anti-odour effectiveness after 30 washes.
The treatment is bluesign® APPROVED, OEKO-TEX® ECO PASSPORT certified, USDA Certified Biobased and dermatologically tested. It complies with ZDHC MRSL 3.1, EU REACH and California Proposition 65.
APRÍtech™, powered by HeiQ Mint
HeiQ Mint is based on mint oil from natural essential oils, infused into the fabric during manufacturing. It is 100% metal free.
We use it on our polyamide performance garments: leggings, sports bras and performance shorts. More than 94% of the treatment remains intact after 20 washes at a maximum of 30°C. Compare that with the silver garments above, which had lost between a third and nine tenths of theirs after ten.
HeiQ Mint is bluesign® approved, ZDHC compliant, suitable for OEKO-TEX® and vegan. The treated fabric has been skin patch tested by Complife, with a non-irritating result.
Three questions to ask any brand
- What gives this garment its odour resistance? A brand should be able to name the technology.
- Does it contain silver or other metals? If so, ask how much is left after washing.
- What testing supports the claim, and after how many washes? "Stays fresh" means little without a number.
We would rather be asked these questions than not. The answers for our own garments are above.
Looking after a treated garment
Odour control does not replace washing. It means you can often wash less.
- Let the garment dry fully after training. A damp top in a gym bag will smell whatever it is treated with.
- After a light session, airing is often enough before you wear it again.
- When it needs washing, 20–30°C is enough. Follow the care label.
Fewer washes mean less wear on the fabric and a garment that lasts longer, which is the point of buying one good training top instead of three.
Further reading: Financial Times, "How toxic is your sportswear?" (subscription required)
Source: Svenskt Vatten, "Silverläckan – en rapport om silver i sportkläder", Meddelande M145, October 2018
