Recycled polyester has gained popularity in the fashion industry as a sustainable alternative, but its environmental impact is more complex than it appears. Approximately 98% of recycled polyester used in clothing is sourced from PET (polyethylene terephthalate) drink bottles, rather than from textile waste. This reliance on bottle recycling creates a significant issue: once PET bottles are transformed into textile fibers, they enter a recycling system that is not equipped to handle most clothing materials. This process leads to downcycling, where the quality of the material decreases, making future recycling difficult. Furthermore, studies indicate that recycled polyester sheds 55% more microfibres than virgin polyester, exacerbating marine pollution. As the fashion industry pushes for more recycled materials, the lack of infrastructure for textile-to-textile recycling remains a major barrier. The European Union's upcoming regulations require all textiles to be durable and primarily composed of recycled fibers by 2030, highlighting the urgency for brands to invest in proper recycling technology. Until the industry addresses its waste management issues, turning bottles into clothing will continue to be a one-way path to landfill.