PQQ

Pyrroloquinoline quinone (PQQ) is a redox cofactor found in trace amounts in fermented soy, kiwifruit, parsley and green tea. Interest in PQQ comes from cell and animal work showing it can stimulate mitochondrial biogenesis — the creation of new mitochondria — through PGC-1alpha signalling, alongside potent redox cycling that lets a single molecule neutralise many oxidants before being spent.

Human evidence is early but consistent in direction. Small randomised trials using 10-20 mg daily for 6-12 weeks have reported reductions in self-reported fatigue, improvements in sleep onset and duration, and modest gains on working-memory and attention tasks in middle-aged and older adults. Markers of oxidative stress and inflammation have shifted favourably in several of these studies. Trials are typically under 100 participants, so effect sizes should be treated as provisional.

PQQ is often paired with CoQ10 on the theory that one builds mitochondrial capacity while the other supports the electron transport chain already in place; the combination has been tested but not convincingly separated from PQQ alone. For most people PQQ is a secondary supplement — worth trialling for persistent low energy or age-related cognitive complaints once sleep, iron, B12, thyroid and vitamin D have been addressed.