What do the charcoal, sugar and clay in this scrub actually do?

The formula combines three components that work through different mechanisms, which is what separates it from a plain sugar scrub:

• Bamboo activated charcoal is a highly porous material that works by adsorption — surface residue, excess sebum and loosened dead skin particles bind to its surface and are carried away when you rinse. This is why charcoal is a common choice for skin that tends to collect oil and impurities.
• Cane sugar crystals provide the mechanical side of exfoliation. As you massage, they physically loosen the outer layer of dry cells. A practical property of sugar as an exfoliant is that the crystals gradually soften and dissolve in water, so the abrasive action naturally becomes gentler the longer you massage.
• Black volcanic clay adds an absorbing element, helping draw surface build-up out during application while giving the formula its mineral clay texture.

Alongside these, a vitamin complex is included for conditioning. Physical exfoliation can leave skin feeling tight or stripped; the conditioning component is there so the finish feels supple rather than dry. In practice this means the scrub aims at two outcomes at once — smoother texture from the polishing, and a nourished feel afterwards — rather than cleansing power alone.