Do Anti-Odour Treatments Contain Heavy Metals or PFAS?

Yes, many conventional anti-odour treatments in activewear do contain heavy metals or PFAS. The three most common approaches are silver-ion finishes, zinc-based compounds, and PFAS (fluorinated) coatings — and each has a real, documented downside: silver leaches into waterways during washing, PFAS are the "forever chemicals" facing increasing regulatory restriction across the EU and US, and zinc/heavy-metal exposure raises separate skin-contact concerns for some wearers.

Here's what each treatment actually is, what the concern with it is specifically, and what a genuinely different approach looks like.

The Three Conventional Anti-Odour Treatments

Why Silver-Ion Treatments Raise Environmental Concerns

Silver-ion is the most common anti-odour treatment in mainstream activewear, largely because it's cheap and effective at killing bacteria on contact. The problem is exactly what makes it effective: it's a heavy metal, and a portion of it washes out of the fabric with every laundry cycle.

That silver enters wastewater systems and, from there, rivers and aquatic ecosystems, where it's toxic to fish and other organisms even at low concentrations. It's also why silver-ion treatments tend to lose effectiveness faster than plant-based alternatives — the mechanism that fights odour is quite literally washing away.

Why PFAS Are Called "Forever Chemicals"

PFAS (per- and polyfluoroalkyl substances) are a family of synthetic compounds valued in textiles for repelling water, oil, and stains — sometimes combined with odour resistance in a single finish. The carbon-fluorine bond that makes them so effective is also what makes them almost impossible to break down: PFAS don't degrade naturally in the environment or, once absorbed, in the human body, which is where the "forever chemicals" name comes from.

Regulatory bodies have taken this seriously in recent years. The EU has moved to restrict several PFAS compounds under REACH, and multiple US states have introduced or passed legislation restricting PFAS in textiles and consumer goods. That regulatory direction reflects a growing scientific consensus that these compounds shouldn't be in continuous contact with skin or accumulating in water systems.

Is Zinc Safer Than Silver?

Zinc-based antimicrobial treatments (zinc oxide or zinc pyrithione) work on a similar principle to silver — a heavy metal that disrupts bacterial activity. It's generally considered to have a somewhat lower environmental persistence than silver, but it's still a heavy metal, still associated with skin sensitivity in some wearers, and still not biodegradable. It's a smaller-scale version of the same trade-off, not a fundamentally different one.

What Plant-Based Anti-Odour Treatments Actually Do Differently

Plant-based anti-odour technologies work on a different mechanism entirely. Rather than killing bacteria with a heavy metal, they use compounds derived from natural sources — wood extractives, mint, and similar plant-derived actives — that inhibit the specific bacterial activity responsible for odour, without introducing a persistent metal or synthetic compound into the fabric or the wastewater stream.

Two examples of this category, both independently certified:

• NordShield — derived from Nordic wood extractives, used in APRÍshield™ treatments on APRÍ's lyocell and cotton garments. Free from silver, zinc, PFAS, and heavy metals. Independently tested to retain 99.9% effectiveness after 30 washes. OEKO-TEX Standard 100 certified.
• HeiQ Mint — a mint-derived technology used in APRÍtech™ treatments on APRÍ's polyamide performance garments (leggings, sports bras, performance shorts). Also free from heavy metals and PFAS. Independently tested to retain 94%+ effectiveness after 20 washes at 30°C.

Both are biodegradable and don't introduce the wastewater or skin-contact trade-offs that silver, zinc, and PFAS treatments carry. They're not the only plant-based technologies on the market, but they illustrate what "heavy-metal-free" and "PFAS-free" actually mean in practice, beyond the marketing language.

How to Check What's in Your Own Activewear

Anti-odour technology isn't always disclosed clearly on a hangtag, but there are a few reliable ways to check:

• Look for a named technology (not just "anti-odour" or "odour control") — a brand using a plant-based treatment will usually name it specifically, since it's a differentiator worth stating.
• Check for OEKO-TEX Standard 100 certification, which tests the finished garment for a defined list of substances including heavy metals — a certified product has been independently verified, not just self-declared.
• If a product claims water-repellency and odour-resistance together in one finish, treat that as a signal worth double-checking — that combination is a common PFAS use case.
• Many mainstream activewear brands still use conventional silver-ion or PFAS-based treatments without prominently disclosing it — if you can't find the specific technology named anywhere, it's worth checking directly with the brand rather than assuming.

For more on how one specific plant-based technology works, see our explainers on what NordShield is and how HeiQ Mint works.

Frequently Asked Questions

Do all anti-odour sportswear treatments contain heavy metals?

No. Silver-ion and zinc-based treatments do contain heavy metals, and they're the most common conventional approach in mainstream activewear. Plant-based alternatives, such as those derived from wood extractives or mint, achieve anti-odour effectiveness through a different mechanism and contain no heavy metals at all.

Is silver-ion anti-odour treatment safe?

Silver-ion treatments are approved for use in textiles and aren't considered acutely dangerous to wear, but they carry a documented environmental concern: silver leaches out of the fabric during washing and accumulates in waterways, where it's toxic to aquatic life even at low concentrations. It's an environmental and sustainability concern more than an immediate personal-safety one.

What is PFAS and why is it being restricted?

PFAS (per- and polyfluoroalkyl substances) are synthetic fluorinated chemicals used in textiles for water and stain repellency, sometimes combined with odour resistance. They're called "forever chemicals" because the chemical bond that makes them effective also makes them extremely resistant to breaking down, so they persist in the environment and in the human body. The EU has restricted several PFAS compounds under REACH, and multiple US states have introduced restrictions on PFAS in consumer textiles.

Are plant-based anti-odour treatments as effective as silver or PFAS?

Independently tested plant-based treatments can match or exceed the durability of conventional treatments. NordShield, for example, is tested to retain 99.9% effectiveness after 30 washes — a higher wash-cycle durability figure than commonly cited for silver-ion treatments, which tend to lose effectiveness as the silver washes out over time.

How can I tell if my activewear uses a heavy-metal-free treatment?

Check for a named technology rather than a generic "anti-odour" claim, and look for OEKO-TEX Standard 100 certification, which independently verifies the finished garment is free from a defined list of substances including heavy metals. If neither is disclosed, it's worth contacting the brand directly to ask what treatment is used.

Does APRÍ use silver, zinc, or PFAS in its anti-odour treatments?

No. APRÍ's lyocell and cotton garments use APRÍshield™ (NordShield technology), and its polyamide performance garments use APRÍtech™ (HeiQ Mint technology). Both are plant-based, free from silver, zinc, heavy metals, and PFAS, and both are independently OEKO-TEX Standard 100 certified.

The Bottom Line

Anti-odour treatment isn't one thing — it's a category with real differences in what's actually in the fabric. Silver and zinc are heavy metals with documented environmental and, for some wearers, skin-contact concerns. PFAS are persistent synthetic chemicals facing active regulatory restriction. Plant-based alternatives exist specifically to avoid all of that, and independently certified versions can match or exceed the conventional options on durability.

The technology used to keep a garment fresh matters as much as whether it works — and it's usually worth the extra minute to find out which category yours falls into.

See also: is lyocell good for sensitive skin? and the no-greenwash guide to sustainable activewear brands.