What Does GRS Certified Mean?

"GRS certified" is something you may come across when looking at recycled polyester. But what does it actually mean, and why does it matter when choosing a product?

The Global Recycled Standard (GRS) is a certification developed by Textile Exchange to verify recycled content and track certified materials through the supply chain. It also includes requirements for social practices, environmental management, and chemical use during processing.

What does GRS actually verify?

GRS applies to products containing at least 20% recycled material. For consumer-facing GRS product claims, the requirement is 50% recycled content.

The important part is traceability. Recycled polyester can pass through several stages before becoming fabric:

Recycled material → fiber → yarn → fabric → finished product

GRS uses a chain-of-custody system to track certified material through these stages. Independent certification bodies audit companies within the certified supply chain, with documentation used to verify certified materials and transactions at every step.

So GRS is not simply a statement that says "this fabric is recycled." It's a framework for verifying and tracking the recycled material behind the claim.

Why recycled polyester?

Polyester is one of the most widely used synthetic fibers in textiles. Using recycled polyester means the starting material comes from recycled sources rather than relying entirely on virgin polyester.

There are measurable differences in some environmental impacts. A peer-reviewed study comparing polyester production, published in the Textile Research Journal, found the water-scarcity footprint of recycled polyester at 1.90 m³ per 100 kg of fabric, compared with 5.98 m³ for virgin polyester — around a 68% difference in the systems assessed. Life-cycle assessments in the same category have also found greenhouse gas emissions running roughly 30–50% lower for recycled polyester, depending on the recycling process used.

The exact environmental benefit varies depending on how the recycled material is collected, processed, and manufactured, so recycled polyester isn't automatically a zero-impact material. But it can be a more considered alternative to virgin polyester — particularly against the scale of the problem it's replacing: an estimated 5 trillion single-use plastic bags are used globally every year, and once discarded, they don't biodegrade — they break into microplastics that persist in water and soil.

Why we chose it for Sena Kai

For Sena Kai, material selection started with the product itself.

Our wet–dry bags need to be durable, water-resistant, lightweight, and practical for repeated use. Recycled polyester allowed us to meet those functional requirements while using recycled content in the outer fabric. Our shell fabric is a GRS-certified recycled polyester paired with a TPU lining, and the paper and board elements in our packaging are FSC-certified.

We chose to work with recycled polyester because the material makes sense for the product — not simply because it gives us a sustainability story to tell. GRS gives us a recognized framework for understanding the recycled content and its supply chain, including the parts we're still working to bring fully into this standard.

For Sena Kai, that's what considered design means: making thoughtful choices about the materials behind the products we use every day.

Carry beautifully. Care deeply.