Final answer:
The Texas Department of Licensing and Regulation (TDLR) prohibits certain substances/products from use in performing cosmetology services.
Step-by-step explanation:
The Texas Department of Licensing and Regulation (TDLR) regulates the cosmetology industry and does prohibit certain substances/products from use in performing cosmetology services. For example, TDLR prohibits the use of methyl methacrylate (MMA), a substance that was commonly used in acrylic nail products but has been found to be hazardous. TDLR also prohibits the use of certain hair dyes that contain prohibited ingredients. These regulations are in place to protect the health and safety of both the clients and the cosmetologists.