# PQQ Plus (Pyrroloquinoline quinone)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/pqq-plus
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-19
**Evidence Score:** 2 / 10
**Category:** Other
**Also Known As:** Pyrroloquinoline quinone, PQQ, 4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylic acid, Methoxatin, 2,7,9-tricarboxy-1H-pyrrolo[2,3-f]quinoline-4,5-dione, Coenzyme PQQ, PQQ disodium salt

## Overview

Pyrroloquinoline quinone (PQQ) is a redox-active quinone cofactor originally identified in bacterial enzyme systems, where it serves as an electron carrier for dehydrogenase enzymes. In human supplementation contexts, PQQ is marketed for [mitochondrial](/ingredients/condition/energy) support and [cognitive enhancement](/ingredients/condition/cognitive), though robust clinical trial evidence in humans remains limited.

## Health Benefits

• No human health benefits can be substantiated - the research dossier contains no clinical trials or human studies
• The compound functions as a redox cofactor in bacterial systems only, based on available evidence
• Acts as an [antioxidant](/ingredients/condition/antioxidant) in bacterial [metabolism](/ingredients/condition/weight-management), though human applications are not documented in the research
• Facilitates electron transfer in bacterial glucose and alcohol dehydrogenases, but human effects are unknown
• Water-soluble properties (3 g/L at 25°C) suggest potential bioavailability, though no human absorption data exists

## Mechanism of Action

PQQ functions as a redox cofactor by cycling between its oxidized (PQQ) and reduced (PQQH2) forms, facilitating electron transfer in bacterial methanol and glucose dehydrogenase enzymes. In vitro studies suggest PQQ may activate the transcription factor PGC-1α, a regulator of [mitochondrial biogenesis](/ingredients/condition/energy), and modulate the PI3K/Akt signaling pathway. It also scavenges [reactive oxygen species](/ingredients/condition/antioxidant) via its ortho-quinone structure, though these antioxidant mechanisms have been demonstrated primarily in bacterial and cell-culture models rather than confirmed human physiology.

## Clinical Summary

Human clinical research on PQQ is sparse and methodologically limited. A small Japanese pilot study (n=17) suggested that 20 mg/day of PQQ disodium salt improved scores on the Stroop color-word test and reduced subjective fatigue after 8 weeks, but the study lacked a placebo control arm. A separate short-term study (n=41) combined PQQ with CoQ10 and reported modest self-reported [memory](/ingredients/condition/cognitive) improvements, making it impossible to attribute effects to PQQ alone. No large-scale, double-blind, placebo-controlled RCTs have been completed, and no regulatory health claims have been substantiated for PQQ in humans.

## Nutritional Profile

PQQ (Pyrroloquinoline quinone) is a tricyclic ortho-quinone compound (C14H6N2O8, molecular weight ~330.21 g/mol) classified as a redox-active cofactor rather than a traditional nutrient. It is not a source of macronutrients (no protein, fat, carbohydrate, or fiber). Typical supplement doses range from 10–20 mg per capsule. PQQ is found in trace amounts in certain foods: natto (~61 ng/g), green tea (~30 ng/g), fermented soybeans (~9–61 ng/g), parsley (~34 ng/g), kiwi fruit (~27 ng/g), and human breast milk (~140–180 ng/mL). Dietary intake from food is estimated at approximately 0.1–1.0 µg/day, which is orders of magnitude below supplemental doses. PQQ functions as a potent redox cycling molecule capable of undergoing thousands of catalytic oxidation-reduction cycles, far exceeding ascorbic acid in this capacity in vitro. It is a non-vitamin cofactor; despite early proposals, it has not been confirmed as an essential vitamin in humans. The 'Plus' formulation typically includes additional compounds such as CoQ10 (ubiquinone, often 100–200 mg), which is a lipid-soluble benzoquinone involved in [mitochondrial](/ingredients/condition/energy) electron transport. Bioavailability data for oral PQQ in humans is limited; animal studies suggest absorption occurs in the gastrointestinal tract with distribution to multiple tissues, but human pharmacokinetic parameters (Cmax, Tmax, half-life, bioavailability percentage) remain poorly characterized in peer-reviewed clinical literature. The disodium salt form (BioPQQ®/PQQ disodium salt) is the most common supplemental form, chosen for water solubility. PQQ contains no significant vitamins or minerals itself. Its primary bioactive mechanism is as an electron carrier/redox cofactor, with demonstrated activity in bacterial pyrroloquinoline quinone-dependent dehydrogenases (e.g., methanol dehydrogenase, glucose dehydrogenase), though equivalent enzymatic roles in human biochemistry have not been established.

## Dosage & Preparation

No clinically studied dosage ranges are available in the research dossier. The FDA GRAS Notice documents chemical properties of PQQ disodium salt but does not establish recommended human doses. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

PQQ disodium salt has been granted Generally Recognized as Safe (GRAS) status in the United States at doses up to 20 mg/day, based on toxicology data rather than extensive clinical safety trials. Mild gastrointestinal discomfort has been reported anecdotally at higher doses. Because PQQ may influence [mitochondrial](/ingredients/condition/energy) electron transport and [antioxidant](/ingredients/condition/antioxidant) pathways, theoretical interactions exist with anticoagulants and drugs metabolized by cytochrome P450 enzymes, though these have not been formally studied. Safety data during pregnancy and lactation is absent, so use is not recommended in these populations.

## Scientific Research

The research dossier contains no human clinical trials, randomized controlled trials, meta-analyses, or PubMed PMIDs evaluating PQQ supplementation in humans. All available evidence focuses on bacterial biochemistry and chemical structure rather than clinical efficacy.

## Historical & Cultural Context

The research contains no information about traditional medicine use or historical applications of PQQ. The compound was first discovered scientifically in 1964 in bacterial systems.

## Synergistic Combinations

Insufficient research to recommend synergistic combinations

## Frequently Asked Questions

### What does PQQ actually do in the human body?

PQQ acts as a redox cofactor, cycling between oxidized and reduced states to transfer electrons, a role well-established in bacterial dehydrogenase enzymes. In human cells, in vitro evidence suggests it may stimulate PGC-1α to promote mitochondrial biogenesis and quench free radicals via its ortho-quinone functional group. However, whether these mechanisms translate to meaningful physiological effects in living humans has not been confirmed by clinical trials.

### Is PQQ safe to take daily?

PQQ disodium salt has received GRAS designation in the US at doses up to 20 mg per day, based primarily on animal toxicology studies and limited short-term human data. No serious adverse events were reported in the small human studies conducted, though gastrointestinal upset has been noted anecdotally at higher doses. Long-term safety data beyond 8 weeks in humans is essentially nonexistent, so caution is warranted with extended use.

### Can PQQ improve memory and cognitive function?

A small uncontrolled Japanese study of 17 adults reported improved Stroop test performance and reduced fatigue after 8 weeks of 20 mg/day PQQ, suggesting a possible cognitive benefit. However, the absence of a placebo control means these results cannot rule out expectation effects or natural fluctuation. At this time, no confirmed clinical evidence supports PQQ as a proven cognitive enhancer in healthy or cognitively impaired adults.

### What is the difference between PQQ and CoQ10?

CoQ10 (ubiquinone) is a well-established lipid-soluble electron carrier in the human mitochondrial electron transport chain, with substantial clinical evidence supporting its use in certain conditions such as CoQ10-deficiency myopathies and heart failure adjunct therapy. PQQ, by contrast, is a water-soluble quinone whose confirmed enzymatic cofactor role is limited to bacterial systems, and its role in human mitochondrial function remains speculative. The two are sometimes combined in supplements, but attributing specific outcomes to PQQ alone when CoQ10 is present is methodologically problematic.

### Does PQQ interact with any medications?

No formally documented drug interactions for PQQ exist in the peer-reviewed literature. Theoretical concerns include potential additive effects with anticoagulants like warfarin due to PQQ's redox-active quinone structure, which is structurally related to vitamin K compounds. Anyone taking medications metabolized by cytochrome P450 enzymes or blood-thinning drugs should consult a healthcare provider before using PQQ supplements, as interaction studies have not been performed.

### What is the current state of clinical research on PQQ in humans?

Currently, there are no published human clinical trials or controlled studies demonstrating health benefits from PQQ supplementation in people. While PQQ functions as a redox cofactor in bacterial systems, evidence supporting its efficacy in human metabolism remains absent from peer-reviewed literature. Most claims about PQQ's benefits to mitochondrial function or cognitive performance are based on preliminary laboratory or animal research, not human studies.

### Are there natural food sources of PQQ I should know about?

PQQ is found in trace amounts in certain foods including fermented soybeans (natto), kiwi fruit, papaya, and some bacterial cultures, though dietary levels are extremely low. Whether consuming these foods provides meaningful amounts of PQQ or produces any biological effect in humans has not been established through clinical research. Supplemental doses used in products are typically much higher than amounts obtainable from food sources.

### Why is PQQ marketed as a supplement if human studies don't support it?

PQQ is marketed based on its demonstrated role in bacterial metabolism and limited in vitro or animal model research suggesting potential antioxidant properties, which fall under the regulatory framework allowing dietary supplement claims without FDA approval. However, the supplement industry distinguishes between theoretical potential and proven human benefit—PQQ's marketing often emphasizes this gap by using cautious language like "may support" rather than definitive claims. Consumers should be aware that marketing presence does not equal clinical validation in humans.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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