These "green" products do not melt anything instantly. They introduce billions of bacteria that secrete enzymes to break down organic waste. The bacteria eat the hair, grease, and soap scum, converting it into carbon dioxide and water.
However, for the average homeowner, the best is actually no product at all: it is a $15 hair catcher for your shower drain and a monthly flush of boiling water with dish soap. drain unblocker products
Caustic cleaners create an exothermic (heat-producing) reaction. When the granules or gel hit water, the temperature inside the pipe can spike to near-boiling levels. This heat melts solid grease into a liquid. Simultaneously, the high pH (13+) turns fats into water-soluble soap (a process called saponification). These "green" products do not melt anything instantly