The chemical texture service that loosens overly curly hair into loose curls or waves is known as:

The process that is designed to loosen overly curly hair into loose curls or waves is known as curl re-formation. This service utilizes chemical solutions to restructure the hair's internal bonds, transforming tightly curled hair into a more relaxed, wavy, or curl pattern. The primary objective of curl re-formation is to create a softer, more manageable texture while still retaining some wave or curl, allowing for a natural and stylish appearance.

In this context, it's important to understand that the other options do not accurately represent this specific service. Relaxation typically refers to a process that straightens very curly or coiled hair rather than loosening it into waves. Re-texturing is a more general term that could encompass multiple services related to altering hair texture and doesn't specifically imply the process of loosening curls. Deep conditioning focuses on the health and moisture of the hair rather than altering its texture. Thus, curl re-formation is the most precise and appropriate choice for describing the service that transforms overly curly hair into loose curls or waves.