PQQ
/ Pyrroloquinoline quinone (small molecule, redox cofactor); proposed mitochondrial biogenesis inducerALIAS · PQQ · Pyrroloquinoline quinone · Methoxatin
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Tier 3. PQQ is a redox-active small-molecule quinone cofactor with rodent mitochondrial-biogenesis literature (Stites 2006 and follow-ups) and small human studies of supplementation (Harris 2013 and a handful of Japanese-language studies). Sold as a dietary supplement in the US; the supplement-grade material is the predominant exposure pathway. No FDA-approved therapeutic use.
PQQ is a tricyclic ortho-quinone first identified as a bacterial enzyme cofactor and subsequently characterised as a redox-active small molecule with antioxidant and electron-transfer properties. The mitochondrial-biogenesis hypothesis derives from rodent studies showing that PQQ deprivation reduces mitochondrial number and function and that supplementation increases mitochondrial markers (PGC-1α, NRF1, mitochondrial DNA content) in liver and other tissues. Whether PQQ functions as a true vitamin in mammals — fulfilling a defined enzyme-cofactor role rather than acting as a non-specific antioxidant — has been debated in the cofactor literature.
Tier 3. Rodent mitochondrial biogenesis literature is the strongest preclinical anchor (Stites 2006; subsequent group follow-ups). Harris 2013 reported a small open-label human study of oral PQQ 20 mg daily for 75 days with effects on inflammatory and metabolic biomarkers. Subsequent small Japanese trials have explored cognitive-function endpoints. No Phase 3 trial; human outcome data are limited.
In published small human studies, well tolerated at oral doses up to 20–40 mg daily. The supplement-grade material has decades of consumer exposure without identified major safety signals, though no comprehensive post-marketing safety database is available.
Regulatory status
- FDA status:
- Not FDA-approved
The 'mitochondrial biogenesis' framing is supported by rodent PGC-1α-pathway data but the human disease-modifying-outcome database does not yet support the geroscience claim. Whether PQQ is a vitamin (fulfilling a defined cofactor role) or a non-specific antioxidant remains unresolved in the mammalian biochemistry literature. Supplement-grade PQQ products vary substantially in dosing and formulation; the published academic studies generally use defined research-grade material that consumer product is not always equivalent to.