Pyrroloquinoline quinone (PQQ) is an antioxidant that acts as a redox catalyst. It is found in many foods and in the soil. There are also a number of dietary supplements that contain PQQ. They are marketed as energy boosters or for improved memory and cognitive health.

The enzymes responsible for producing PQQ are called quinoproteins. These proteins have radial symmetry and contain oxidoreductase and methanol dehydrogenase activity.

Pyrroloquinoline quinone is known to be a neuroprotective agent that has been associated with improved cognition and sleep in aged humans. In addition, PQQ is thought to have anti-oxidant properties.

PQQ has also been shown to help protect brain cells from damage caused by strokes. This is believed to be due to its ability to promote the production of new mitochondria. Also, it helps reduce oxidative stress and protects neurons from the damaging effects of prolonged over-stimulation.

Pyrroloquinoline quinone has been found to be a very potent inhibitor of protein tyrosine phosphatase 1B (PTP1B), an enzyme that metabolizes tyrosine. Prolonged over-stimulation of neurons is associated with seizures and neurodegenerative diseases.

It is believed that PQQ enhances the expression of the nerve growth factor, or NGF. Nerve growth factor is important for maintaining neuroplasticity, a process in which neurons branch out and communicate. This helps the brain form connections and retain memories.

Moreover, it is said to be an effective redox cofactor that supports the creation of new mitochondria. While there is no known optimal dose for daily use, most dietary supplements are sold in the range of 20-40 mg.