PQQ is a naturally occurring compound found in various foods, including fermented soybeans, green tea, spinach, and certain fruits. In the human body, it plays a vital role in cellular metabolism and mitochondrial function. Mitochondria, often referred to as the powerhouses of cells, are critical for energy production. PQQ has been shown to stimulate the growth of new mitochondria, a process known as mitochondrial biogenesis, which can lead to improved energy metabolism and overall cellular health.