How does gray hair care differ from hair dye?

The purpose of the two types of procedures is different: the dyeing and covering method is to dye the gray hair darker, and the effect is immediate, but the newly grown white hair will reappear and requires regular touch-ups; the maintenance type service (scalp cleansing, nutritional support, relaxation) aims at a healthy scalp and does not change the color of the gray hair (PMID 32654282).

It’s understandable that you don’t want to dye your hair frequently, but you need to understand: maintenance cannot replace hair dyeing and cover up, nor can it make white hair turn black naturally. If the organization implies that it "maintains and prevents gray hair" and "the more you nourish it, the darker your hair will become", this is exaggerated propaganda.