Pyrroloquinoline quinone (PQQ) is a redox cofactor and antioxidant compound that has drawn interest for its potential neuroprotective benefits. Preclinical studies, primarily in animal models and cell cultures, have demonstrated PQQ’s capacity to protect nerve cells from oxidative stress, excitotoxicity, and apoptosis—mechanisms involved in various types of nerve damage. For example, research has shown that PQQ can reduce infarct size and neuronal loss in rodent models of stroke and attenuate neurotoxicity in models of Parkinson’s disease. Its neuroprotective effects are attributed to its ability to scavenge free radicals, modulate mitochondrial function, and influence cell signaling pathways such as those involved in nerve growth factor (NGF) production.

However, despite promising results in animal and in vitro studies, clinical evidence in humans is extremely limited. No large-scale, high-quality randomized controlled trials have evaluated PQQ for treating or supporting recovery from nerve damage in humans. Most human research with PQQ has focused on cognitive function or fatigue rather than direct measures of nerve repair or regeneration. As such, while there is a scientific rationale and basic research foundation for PQQ’s use in nerve damage, its translation into clinical practice remains unproven. The overall evidence level is therefore moderate in preclinical studies but weak in terms of clinical validation.