What is a disadvantage of glycolysis?

A disadvantage of glycolysis is that it produces a relatively small amount of ATP (only two ATP molecules per glucose molecule) compared to more energy-efficient pathways like oxidative phosphorylation. Additionally, glycolysis generates NADH, which requires regeneration of NAD+ through fermentation under anaerobic conditions. In the long term, the accumulation of lactic acid (or ethanol) from fermentation can be toxic.