produced by fermentation, high purity, high bioavailability, water-soluble.

From wikipedia:

Pyrroloquinoline quinone (PQQ) was discovered by J.G. Hauge as the third redox cofactor after nicotinamide and flavin in bacteria (although they hypothesised that it was naphthoquinone). Anthony and Zatman also found the unknown redox cofactor in alcohol dehydrogenase and named it methoxatin. In 1979, Salisbury and colleagues as well as Duine and colleagues extracted this prosthetic group from methanol dehydrogenase of methylotrophs and identified its molecular structure. Adachi and colleagues identified that PQQ was also found in Acetobacter.

These enzymes containing PQQ are called quinoproteins. Glucose dehydrogenase, one of the quinoproteins, is used as a glucose sensor. Subsequently, PQQ was found to stimulate growth in bacteria. In addition, antioxidant and neuro-protective effects were also found.

The purported benefits of pyrroloquinoline quinone supplementation include:An overall improvement in energy levelsImproved cognitive function and memoryReduction in mitochondrial degradationIncreased skin elasticityNeuro-protectantCardio-protectantEnhanced nerve growthThe purported benefits of pyrroloquinoline quinone supplementation include:An overall improvement in energy levelsImproved cognitive function and memoryReduction in mitochondrial degradationIncreased skin elasticityNeuro-protectantCardio-protectantEnhanced nerve growth

Pyrroloquinoline quinone, PQQ