← PQQ

Mitochondrial Health and Cognition

How pyrroloquinoline quinone supports mitochondrial biogenesis, protects neurons, and improves cognitive performance in aging adults

PQQ (pyrroloquinoline quinone) is a small molecule found naturally in soil, fermented foods, and human breast milk. Unlike most supplements, PQQ works at the most fundamental level of cellular energy: it activates PGC-1α, the master switch that tells your cells to build new mitochondria [1]. More mitochondria mean more cellular energy, better stress resilience, and slower cellular aging. Human trials have found that 20 mg/day for 12 weeks significantly improves memory, attention, and executive function in older adults [3][4]. It also reduces markers of inflammation — including CRP and IL-6 — in healthy people at relatively low doses [2].

How PQQ Works

PQQ is not a vitamin in the strict sense, but it behaves like one: animal studies show that a diet deficient in PQQ produces stunted growth, impaired reproduction, and immune dysfunction — all reversible with PQQ repletion [6]. This vitamin-like behavior sets it apart from most antioxidant supplements.

Mitochondrial Biogenesis: The Core Mechanism

The most important thing PQQ does is stimulate the creation of new mitochondria — a process called mitochondrial biogenesis. Here's how:

PQQ activates CREB (cAMP response element-binding protein) by phosphorylating it at serine-133
Activated CREB drives increased transcription of PGC-1α, the master regulator of mitochondrial biogenesis
PGC-1α then activates NRF-1, NRF-2, and TFAM — transcription factors that orchestrate the construction of new mitochondria
The result: more mitochondrial DNA, more mitochondrial enzymes, and higher cellular oxygen consumption [1]

A second pathway runs through NAD+ metabolism: PQQ enhances NAMPT activity, raising cellular NAD+ levels, which activates sirtuins (SIRT1, SIRT3), which in turn deacetylate and activate PGC-1α [6]. This means PQQ and NAD+ precursors like NMN or NR likely work through overlapping mechanisms.

Antioxidant Properties

PQQ is a potent antioxidant in biological systems, protecting mitochondria from lipid peroxidation and respiratory chain damage. Importantly, it is a redox cycling compound — it can be reduced and re-oxidized many times, giving it catalytic antioxidant activity rather than a single-use protective effect. One study estimated PQQ undergoes up to 20,000 redox cycles before degradation, far more than vitamin C or E.

Neuroprotection

PQQ protects neurons through several mechanisms: reducing excitotoxic glutamate damage, inhibiting the formation of neurotoxic amyloid proteins, and increasing BDNF (brain-derived neurotrophic factor), which supports neuronal survival and plasticity. A 2024 RCT in adults with mild cognitive impairment found that PQQ supplementation significantly raised serum BDNF levels and improved brain N-acetyl aspartate — a marker of neuronal integrity measured by MRI spectroscopy [7].

Cognitive Effects in Humans

Two well-designed RCTs in older adults have shown meaningful cognitive improvements with 20 mg/day PQQ for 12 weeks:

Memory and executive function: A 2022 RCT (n=58, average age 71) found significant improvements across composite memory, verbal memory, complex attention, cognitive flexibility, and motor speed versus placebo [3]. Participants also reported fewer everyday forgetfulness complaints on a validated questionnaire.

Brain blood flow: A 2016 RCT (n=41, healthy elderly adults) found improved Stroop test performance — a measure of selective attention and executive function — along with objective increases in prefrontal cortex blood flow measured by near-infrared spectroscopy [4]. This cerebral hemodynamic evidence helps explain the cognitive effects mechanistically.

Both trials used 20 mg/day and reported no adverse events. The effect sizes were moderate, and most participants showed improvement regardless of baseline cognitive status.

Anti-Inflammatory Effects

A human crossover study gave healthy adults either a single dose (0.2 mg/kg) or a short multi-day course (0.3 mg/kg/day for 76 hours) of PQQ and measured a comprehensive metabolomic panel [2]. Both protocols produced significant reductions in plasma CRP and IL-6 — key markers of systemic inflammation — along with reductions in TMAO, a metabolite linked to cardiovascular risk. Standard lipids, glucose, and clinical labs were unaffected. This is notable: anti-inflammatory effects at doses achievable through supplementation, without metabolic disruption.

Dosing and Food Sources

Supplement dose: 10–20 mg/day. Most clinical trials used 20 mg/day; some used 21.5 mg. No adverse effects have been reported at these doses, and the safety margin is enormous — the NOAEL in 90-day animal studies exceeded 600 mg/kg/day [8].

Food sources: PQQ is found in small amounts in many foods — kiwi fruit, green peppers, parsley, papaya, and green tea are among the richest dietary sources. However, dietary intake is estimated at just 0.1–1 mg/day, far below the doses used in cognitive trials. Fermented natto is a notably concentrated source.

Forms: PQQ disodium salt (BioPQQ, mnemoPQQ) is the form used in clinical trials and is the standard supplement form. It is stable, well-absorbed, and has robust safety data [8].

Synergies: PQQ is often combined with CoQ10, as both support mitochondrial function through complementary mechanisms — PQQ builds new mitochondria, CoQ10 fuels the ones you have. See our CoQ10 page for more. For the NAD+ pathway overlap, see our B vitamins page.

Evidence Review

Mitochondrial Biogenesis: Mechanistic Foundation

The foundational mechanistic paper is Chowanadisai et al. (2009, Journal of Biological Chemistry, PMID 19861415) [1]. Using cell and animal models, this study demonstrated that PQQ phosphorylates CREB at serine-133 within minutes of exposure, upregulating PGC-1α mRNA and protein in a dose-dependent manner. Downstream markers of mitochondrial biogenesis — mitochondrial DNA content, citrate synthase activity, cytochrome c oxidase activity, and cellular oxygen consumption — all increased significantly. PQQ pretreatment also protected cells from mitochondrial toxins (rotenone, antimycin A, sodium azide), reducing superoxide generation. This paper established the mechanistic framework that all subsequent PQQ research has built on.

The Jonscher et al. (2021, Biomolecules) review [6] extended this framework, documenting a second biogenesis pathway: PQQ → NAMPT activation → elevated NAD+ → sirtuin activation → PGC-1α/NRF-1/NRF-2/TFAM activation. The review also catalogued vitamin-deficiency-like phenotypes in PQQ-deprived animals (reduced litter size, impaired growth, immune dysregulation) and argued for conditional vitamin classification — a designation that would require further human nutritional data to be formalized.

Human Evidence: Inflammation and Metabolism

Harris et al. (2013, Journal of Nutritional Biochemistry, PMID 24231099) [2] is the primary human metabolomics study. Ten healthy adults (5F/5M) completed a crossover protocol with single-dose and short multi-day PQQ. The study used comprehensive metabolomic profiling (NMR spectroscopy of plasma and urine) rather than a panel of pre-selected biomarkers, giving an unbiased view of PQQ's effects. Significant findings included decreased plasma CRP, decreased IL-6, and decreased urinary TMAO — all markers with established cardiovascular and inflammatory relevance. No effects on standard clinical chemistry. Limitations: very small sample, no placebo control in the crossover design, short duration.

Cognitive Function: RCT Evidence

Shiojima et al. (2022, JANA, PMID 34415830) [3]: 66 healthy adults aged 65+ (58 completers) were randomized to 21.5 mg/day mnemoPQQ or placebo for 12 weeks. The CNS Vital Signs computerized cognitive battery was used. Significant improvements in the PQQ group versus placebo (p<0.05) across: composite memory (verbal and visual combined), verbal memory, reaction time, complex attention, cognitive flexibility, executive function, and motor speed. The DECO questionnaire (everyday forgetfulness) and MMSE-J also improved significantly. This is the most comprehensive cognitive RCT for PQQ and the largest in terms of outcome breadth.

Itoh et al. (2016, Adv Exp Med Biol, PMID 26782228) [4]: 41 elderly subjects in a double-blind 12-week RCT with 20 mg/day BioPQQ. The key methodological strength is the use of functional near-infrared spectroscopy (fNIRS) to measure prefrontal cortex hemodynamics during cognitive tasks — providing an objective, physiological measure rather than self-report. The PQQ group showed significantly improved Stroop interference ratios (selective attention/executive function) and increased prefrontal blood flow during cognitive tasks. Participants with lower baseline cognitive scores showed the largest improvements. No adverse events reported.

Baltic et al. (2024, J Nutr Health Aging, PMID 38908296) [7]: 34 elderly participants with mild cognitive impairment (MCI) in a 6-week RCT. The supplement was a dihydrogen-PQQ combination, which complicates attribution of effects solely to PQQ. Serum BDNF was significantly elevated at follow-up versus placebo (p=0.01). The brain orientation domain of ADAS-Cog improved (p=0.03). Cerebral oxygenation increased from 48.4% to 52.8% (p=0.005). MRS showed increased N-acetyl aspartate (neuronal integrity marker) at 7 of 13 brain regions measured (p≤0.05). Limitations: small n, short duration (6 weeks), combination supplement, predominantly female sample.

Exercise and Muscle Mitochondrial Biogenesis

Hwang et al. (2020, Journal of the American College of Nutrition, PMID 31860387) [5] conducted a 6-week RCT with 23 untrained males undergoing supervised endurance training, randomized to 20 mg/day PQQ or placebo. Primary aerobic endpoints (VO2 peak, time to exhaustion) improved similarly in both groups — PQQ did not enhance aerobic performance beyond training alone. However, skeletal muscle biopsies showed significantly greater increases in PGC-1α protein content from baseline in the PQQ group (p<0.05), confirming that the mitochondrial biogenesis mechanism observed in cell studies translates into measurable protein changes in human muscle tissue. This is the only PQQ study to provide direct human muscle biopsy evidence.

Safety Profile

Shiojima et al. (2022, Toxicology Mechanisms and Methods, PMID 35546737) [8] provides the comprehensive preclinical safety package for the mnemoPQQ form. Oral LD50 was 1,825 mg/kg (males) and 1,410 mg/kg (females) in Wistar rats. The 90-day NOAEL exceeded 600 mg/kg/day — no systemic toxicity, no adverse hematology, no hepato- or nephrotoxicity, no reproductive toxicity, no organ pathology. Genotoxicity assessment was negative across Ames test, mammalian cell gene mutation assay, and in vivo micronucleus assay. Non-irritating to skin and eyes. At the standard 20 mg/day human dose, the safety margin relative to NOAEL is effectively unmeasurable — several orders of magnitude.

All clinical trials reported no adverse events at 20–21.5 mg/day. GI tolerance appears excellent. No drug interactions have been reported in the literature, though data is limited.

Confidence Assessment

The mechanistic evidence for PQQ's CREB/PGC-1α mitochondrial biogenesis pathway is robust and replicated across cell and animal models. Human translation is supported by the Hwang et al. (2020) muscle biopsy data showing actual PGC-1α protein increases in human tissue.

The cognitive RCT data is promising but carries important caveats: trials are small (n=10–58), all three major Japanese trials have industry connections to Mitsubishi Gas Chemical (the BioPQQ patent holder), and most participants are Japanese elderly adults — limiting generalizability. The consistent directional effect across multiple cognitive domains and across independent study designs (metabolic, fNIRS, neuroimaging) is encouraging. Independent large-scale replication with diverse populations is still needed to firmly establish the clinical effect size.

Overall confidence: moderate for mitochondrial biogenesis mechanism (strong preclinical, good human translation), moderate for cognitive benefits in older adults (consistent but small industry-linked trials), low-moderate for anti-inflammatory effects (one small human study, strong preclinical signal).

References

Pyrroloquinoline Quinone Stimulates Mitochondrial Biogenesis through cAMP Response Element-binding Protein Phosphorylation and Increased PGC-1alpha ExpressionChowanadisai W, Bauerly KA, Tchaparian E, Wong A, Cortopassi GA, Rucker RB. Journal of Biological Chemistry, 2009. PubMed 19861415 →
Dietary pyrroloquinoline quinone (PQQ) alters indicators of inflammation and mitochondrial-related metabolism in human subjectsHarris CB, Chowanadisai W, Mishchuk DO, Satre MA, Slupsky CM, Rucker RB. Journal of Nutritional Biochemistry, 2013. PubMed 24231099 →
Effect of Dietary Pyrroloquinoline Quinone Disodium Salt on Cognitive Function in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group StudyShiojima Y, Takahashi M, Takahashi R, Moriyama H, Bagchi D, Bagchi M, Akanuma M. Journal of the American Nutritional Association, 2022. PubMed 34415830 →
Effect of the Antioxidant Supplement Pyrroloquinoline Quinone Disodium Salt (BioPQQ) on Cognitive FunctionsItoh Y, Hine K, Miura H, Uetake T, Nakano M, Takemura N, Sakatani K. Advances in Experimental Medicine and Biology, 2016. PubMed 26782228 →
Effects of Pyrroloquinoline Quinone (PQQ) Supplementation on Aerobic Exercise Performance and Indices of Mitochondrial Biogenesis in Untrained MenHwang PS, Machek SB, Cardaci TD, Wilburn DT, Kim CS, Suezaki ES, Willoughby DS. Journal of the American College of Nutrition, 2020. PubMed 31860387 →
Pyrroloquinoline-Quinone Is More Than an Antioxidant: A Vitamin-like Accessory Factor Important in Health and Disease PreventionJonscher KR, Chowanadisai W, Rucker RB. Biomolecules, 2021. PubMed 34680074 →
The impact of six-week dihydrogen-pyrroloquinoline quinone supplementation on mitochondrial biomarkers, brain metabolism, and cognition in elderly individuals with mild cognitive impairment: a randomized controlled trialBaltic S, Nedeljkovic D, Todorovic N, Ranisavljev M, Korovljev D, Cvejic J, Ostojic SM. Journal of Nutrition, Health and Aging, 2024. PubMed 38908296 →
Safety assessment of a novel, dietary pyrroloquinoline quinone disodium salt (mnemoPQQ)Shiojima Y, Deshmukh N, Moriyama H, Soman Y, Nalge P, Randhe M, Bagchi M, Bagchi D. Toxicology Mechanisms and Methods, 2022. PubMed 35546737 →