In its simplest form, Remy hair and Non-Remy hair differ in the way the hair is collected – when you can definitively distinguish the root end from the tip end of each hair shaft, the hair is classified as Remy hair; if you cannot, it is classified as Non-Remy hair. Remy hair is bundled up or put in rubber bands before it is cut and collected.
Remy hair does not guarantee that the hair shaft has cuticle on it. Most manufacturers of hair products use harsh acids to remove or smooth the cuticle before the pigment reduction process primarily due to a lack of technology needed to process hair with the cuticle intact. The only way of knowing that the hair is authentically Remy is if the hair products still have cuticles intact; in order for Non-Remy hair to be used in finished hair products the cuticles have to be removed thoroughly or the hair will tangle and matte excessively.
Cuticle Intact Remy hair is more desirable than Non-Remy hair for a number of reasons; primarily however, cuticle affects the absorption and reflection of light which ensures vibrant colors as well as maintaining the integrity of the hair. Hair cuticles protect the cortex and manage the moisture absorption and retention of each hair shaft. Hair that cannot regulate moisture effectively is prone to becoming dry, tangled and damaged.