Yes, they do, and it's a positive indication for your skin!
Only fabrics that have been treated with formaldehyde or resin can provide a wrinkle-resistant effect. However, formaldehyde can cause irritation for sensitive skin. It is released when these fabrics are washed and is harmful to the environment. Therefore, we do not treat our TENCEL™ sheets with any form of resin, including formaldehyde.
If you want to maintain your sheets as wrinkle-free as possible, we suggest removing them promptly after washing and allowing them to air dry on a line. Use a low heat setting on an iron if needed.