When we set out to build Viren, one of the first questions we asked was simple: what's actually in the fabrics we train in?
It turned out to be a harder question to answer than we expected. Performance fabrics are extensively tested for what they do — how they stretch, wick sweat, hold their shape. But there's far less consistent, independently verified information about what they contain.
That gap led us to OEKO-TEX® Standard 100 — an independent certification that we now hold across every Viren range. In this article, we want to explain what it actually involves, what it tests for, and why we think it matters — especially for activewear that's in direct, sustained contact with your skin during exercise.
What is OEKO-TEX® Standard 100?
OEKO-TEX® Standard 100 is an independent textile certification issued by the OEKO-TEX® Association — a group of independent textile research and testing institutes based in Europe. It's one of the most widely recognised fabric safety standards in the world, used across the medical, childrenswear and sportswear industries.
Crucially, it is not a self-declared certification. A brand cannot design its own badge and call itself OEKO-TEX® certified. The certification is earned through independent laboratory testing and verified by a third party — the OEKO-TEX® Association itself.
What does OEKO-TEX® Standard 100 test for?
The certification tests textile products against a list of over 100 substances. These include:
- Pesticides and herbicides
- Heavy metals including lead, cadmium and mercury
- Formaldehyde
- Chemical dyes and colorants
- pH levels
- Phthalates
- Allergenic dyes
- Flame retardants
The limit values — the maximum permitted levels of each substance — are set based on how the product is used and how much skin contact it involves. This is where sportswear faces a particularly high bar.
Product Class II — direct contact to skin
Under the OEKO-TEX® framework, textile products are grouped into four classes based on their intended use and proximity to skin. Sportswear — including leggings, sports bras and training tops — falls into Product Class II: products with direct contact to skin.
This means sportswear is held to more stringent limit values than, for example, outerwear or furnishing fabrics. The reasoning is straightforward: a product worn directly against your skin for extended periods, in conditions of heat and sweat, warrants closer scrutiny than a product worn over other layers.
Does OEKO-TEX® apply to the finished garment or just the fabric?
This is one of the most commonly misunderstood aspects of the certification — and it's worth being precise about.
At Viren, our OEKO-TEX® Standard 100 certification applies to the finished garment. Not just the outer fabric. Every component that makes up the garment — fabric, lining, trim, bra cups, elastics, sewing thread, woven labels, drawcords — is covered by the certification.
Before we can submit for certification, we are required to obtain OEKO-TEX® compliance documentation from every manufacturer supplying every component we use. Every supplier in our chain has to demonstrate compliance. This is one of the reasons the certification process is time-consuming — coordinating documentation across a textile supply chain takes significant effort.
How often is the certification renewed?
OEKO-TEX® Standard 100 certification is not a one-time badge. It is renewed annually.
Each year, we go through a full process — including an audit of our supply chain and processes — to maintain the certification. The commitment doesn't end at launch. It has to be re-earned, every year, without exception.
This annual renewal is one of the things that gives the certification its credibility. A certificate issued three years ago and never renewed tells you very little about what a product contains today. An annually renewed certification with a current expiry date tells you considerably more.
Why did Viren choose to certify before launching?
We made OEKO-TEX® Standard 100 certification the first requirement for every range we launched — before a single product went on sale.
It wasn't the easy path. The process added cost and time at a point when both were in short supply. In some cases it required us to go back to the drawing board: our original sports bra linings didn't meet the standard, so we changed them. That meant re-sourcing materials, re-sampling and re-testing before we could proceed.
We made this decision because we believe what touches your skin matters. Especially during exercise — when your body heats up, your pores open, and your kit is in sustained contact with your skin for hours at a time. That context deserves a higher standard of scrutiny.
Certification isn't legally required in the activewear industry. No regulation demands it. But we think the absence of a legal requirement isn't a good enough reason to skip something that matters. So we didn't.
How can I verify Viren's certification?
Our certification documents — one for each range — are publicly available on our No Harm Done page at viren.com/pages/no-harm-done. The certification numbers, issuing laboratory and scope of each certificate are all listed there.
You can also verify any Viren certification number directly on the OEKO-TEX® website by entering the certificate number in their public database. We don't ask you to take our word for it. We ask you to check.
What does this mean for you?
When you train in Viren kit, you're wearing activewear that has been independently tested — not just marketed as clean. The certification number on our No Harm Done page is real, current, and verifiable by anyone.
We think that's worth knowing. And we think you deserve to be able to check it yourself.
Related reading: Why We Got OEKO-TEX® Certified — and What That Process Actually Involves · The Viren Journal