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Recycled polyester, often made from post-consumer plastic bottles or discarded polyester garments, is generally considered a more sustainable alternative to virgin polyester. However, its impact on health and the environment can still raise some concerns.

Health Concerns:

1. Chemical Contaminants: The process of recycling plastic bottles or old polyester fabrics into new fibers can introduce contaminants. In some cases, harmful chemicals, like antimony (a metalloid used as a catalyst in PET production) and other residuals from dyes or coatings, can persist in the recycled fibers. These might potentially pose a risk to human health, particularly through long-term exposure or if the fabric is worn close to the skin for extended periods.
2. Microplastics: Recycled polyester, like virgin polyester, is a type of plastic, and washing garments made from it can release microplastics into waterways. These tiny plastic fibers are difficult to filter out and can eventually make their way into the food chain, potentially affecting human health. Some studies have raised concerns about the long-term effects of microplastic ingestion.
3. Off-Gassing: Some synthetic fibers, including polyester (recycled or not), can off-gas volatile organic compounds (VOCs), especially when new. This is more of an issue with low-quality fabrics, but it can still pose a minor concern for indoor air quality or skin irritation for sensitive individuals.

Environmental Concerns:

While recycled polyester is considered more eco-friendly than virgin polyester because it reduces plastic waste, it still has environmental costs:

• Energy Consumption: The process of recycling plastic into polyester fibers requires significant energy, although it is generally lower than the energy needed to produce virgin polyester.
• Microplastic Pollution: Even though recycling polyester can divert waste from landfills, washing recycled polyester items still contributes to microplastic pollution in the environment.
• Limited Recycling: Polyester fibers degrade with each recycling process, which limits the number of times they can be recycled. This means it isn't a fully circular solution in the long run.

Conclusion:

Recycled polyester itself isn’t inherently "bad" for you in terms of direct health risks, especially when compared to conventional, virgin polyester. However, it is still a synthetic material, and its production and disposal have environmental implications. If you are concerned about the health or environmental impact of synthetic fibers, you may want to consider natural alternatives like organic cotton, wool, or hemp, though these have their own environmental trade-offs.

If you choose recycled polyester, you can reduce microplastic pollution by washing your garments with a microfiber-catching filter or in a laundry bag designed to catch these fibers.