For synthetic activewear, which certification builds the most brand trust: GRS, OEKO-TEX®, or both?

For synthetic activewear (recycled nylon/polyester), GRS + OEKO-TEX® typically deliver the strongest brand value—GRS supports recycled-content credibility and traceability, while OEKO-TEX® strengthens consumer trust with safety testing. For organic cotton-focused products, GOTS is often the strongest signal.