Pyruvate is typically considered the last molecule produced in glycolysis. Under aerobic conditions pyruvate is transformed into acetyl-CoA, which then enters the citric acid cycle. Under anaerobic conditions, however, something else must be done to oxidize all the NADH formed in glycolysis.

1. In animal cells and lactic acid bacteria, pyruvate is converted to lactate. In this case, NADH adds electrons to pyruvate, forming NAD⁺ and lactate. The NAD⁺ can then catalyze reaction 6 of further glycolysis reactions. Lactate appears to be produced under aerobic cellular conditions as well, however, so the role of lactate formation is not completely clear.

2. Yeasts recycle NADH to NAD⁺ by alcoholic fermentation:

Pyruvate ->acetaldehyde ->ethanol. The last step converts NADH to NAD⁺.

The reduction of acetaldehyde to ethanol is coupled to the oxidation of NADH to NAD⁺.