What Is PQQ? Pyrroloquinoline Quinone & the 20mg Novel-Food Limit

The Longevity Series · Explainer

What is PQQ?

A bacterial enzyme cofactor. A trace compound in kiwi fruit and natto. A regulated novel food with a legal ceiling of 20mg a day. And — genuinely unresolved — possibly or possibly not a vitamin. Here's what pyrroloquinoline quinone actually is, without the claims nobody is allowed to make.

C₁₄H₆N₂O₈ molecular formula 0.1–1mg typical dietary intake 20mg GB legal maximum 0 authorised health claims

What is PQQ — pyrroloquinoline quinone explained, summary

PQQ stands for pyrroloquinoline quinone, also known as methoxatin. It is a small quinone compound first described in the late 1970s as a redox cofactor in certain bacterial enzymes, filling a role broadly comparable to that of NAD and FAD elsewhere in biology. PQQ occurs naturally in soil and in small quantities in a range of plant foods, most commonly cited being kiwi fruit, natto or fermented soybeans, green tea, parsley, green peppers and cocoa. Estimated human dietary intake is roughly 0.1 to 1.0 milligrams per day, well below supplemental amounts. Supplement-grade PQQ is manufactured by bacterial fermentation rather than plant extraction, because plants contain too little to be practical. It is supplied as PQQ disodium salt, the sodium salt form, which is more stable than the free acid and is the form covered by regulatory authorisation. In Great Britain and the European Union, PQQ disodium salt is a regulated novel food. The authorisation sets a maximum permitted daily intake of 20 milligrams for adults and excludes pregnant and breastfeeding women from the authorised population. There are no authorised United Kingdom or European Union health claims for PQQ, meaning no product may lawfully state what it does for energy, mitochondria, cognition or ageing. Whether PQQ should be classified as a vitamin is genuinely contested. A 2003 paper published in Nature proposed a vitamin-like role for PQQ in mammals. Subsequent work disputed this, arguing that no specific mammalian enzyme requiring PQQ as a cofactor had been demonstrated and that a true deficiency state had not been established. The question remains unresolved. PQQ is not classified as a vitamin in UK food law, has no Nutrient Reference Value, and carries no authorised claims. Published human studies on PQQ have generally been small, using doses around 20 milligrams per day over periods of several weeks to a few months.

The Compound

A bacterial cofactor that ended up in supplements.

PQQ — pyrroloquinoline quinone, sometimes called methoxatin — was first characterised in the late 1970s in bacteria. It's a quinone, meaning it flips easily between oxidised and reduced forms, and that property is what makes it useful biologically.

In certain bacteria, PQQ acts as a redox cofactor: a small non-protein molecule that an enzyme needs in order to do its job. If that sounds familiar, it should — NAD and FAD do the same kind of work in other organisms. PQQ was, in effect, a third member of that family discovered in bacteria that oxidise methanol and glucose.

That's its uncontroversial identity. Everything that came afterwards — the interest in supplements, the question of whether mammals need it — is downstream of that finding, and considerably less settled.

Full name
Pyrroloquinoline quinoneAlso called methoxatin
Molecular formula
C₁₄H₆N₂O₈
Class
QuinoneWater-soluble, heat-stable
First described
Late 1970sAs a redox cofactor in bacterial enzymes
Supplement form
PQQ disodium saltThe form covered by GB and EU authorisation
UK status
Authorised novel foodMax 20mg/day for adults; excludes pregnancy and breastfeeding
Authorised health claims
NoneNo GB or EU claim exists for PQQ
The unresolved bit

Is PQQ a vitamin? Nobody has settled it.

You'll find confident answers to this in both directions, and neither deserves the confidence. Here's the actual state of play.

In 2003, a paper in Nature proposed that PQQ has a vitamin-like role in mammals — that it isn't merely a bacterial curiosity but something animals require. That's the origin of the "PQQ is a vitamin" framing you still see repeated on supplement packaging two decades later.

It was disputed afterwards. The core objections were that no specific mammalian enzyme had been shown to require PQQ as a cofactor, and that a genuine deficiency state — the thing that actually defines a vitamin — hadn't been demonstrated in humans. The proposed mechanism didn't hold up in the way the original paper suggested.

Where that leaves us: genuinely unresolved. PQQ is clearly a cofactor in bacteria. Whether it functions as a required nutrient in humans is not established, and honest sources say so.

The regulatory position, by contrast, is not ambiguous at all: PQQ is not classified as a vitamin in UK food law. It is regulated as a novel food. It has no Nutrient Reference Value, so no product can express a serving as a "%NRV" the way magnesium or vitamin C can. And it carries no authorised health claims. If a pack calls PQQ a vitamin, that is a marketing decision rather than a regulatory one.

In Food

You already eat a little of it.

PQQ occurs in soil and turns up in small quantities across a range of plant foods. The ones most commonly cited in the literature:

Food Notes
Natto Fermented soybeans — among the higher food sources cited
Kiwi fruit The most frequently mentioned fruit source
Green tea Also a source of a range of other polyphenolic compounds
Parsley Cited among leafy sources
Green peppers Cited among vegetable sources
Cocoa Detected in small amounts

The amounts are genuinely tiny. Estimated total dietary intake in humans is usually placed somewhere around 0.1 to 1.0 milligrams per day. Set that against the 20mg ceiling for supplements and the gap is roughly twenty to two hundred fold.

That gap is the entire practical reason supplemental PQQ exists. It also means the "it's found in kiwi fruit" framing, while true, doesn't tell you much — you would need an implausible quantity of kiwi to approach a supplemental dose.

Manufacture

Made by bacteria, not extracted from plants.

Since plants contain too little PQQ to make extraction viable, supplement-grade material is produced by bacterial fermentation. Certain bacteria generate PQQ as part of their ordinary metabolism; it's harvested from that process and purified.

The purified compound is then supplied as PQQ disodium salt — the sodium salt rather than the free acid, because it's more stable and easier to handle. That's the form named in the GB and EU novel food authorisation, and it's the form that should appear on a label.

This matters when you're reading a pack. A label saying only "PQQ" or "pyrroloquinoline quinone" without specifying the disodium salt leaves you unable to confirm the product uses the authorised form, or to check the stated milligram figure against the permitted limit. See our quality and testing page for how we verify ingredient identity on every batch.

The Research

What the studies actually examined.

Here is where we have to be careful, and where most PQQ pages aren't. There are no authorised health claims for PQQ, which means we cannot lawfully tell you what it does — and neither can anyone else, however the sentence is phrased.

What we can describe is study design: how many people, what dose, how long. That's factual and verifiable, and it lets you go and read the primary literature yourself rather than taking a supplement company's summary of it.

Characteristic What the published human work looks like
Typical dose studied Around 20mg per day — the same figure as the GB authorised maximum
Typical duration From a few weeks up to a few months
Typical size Small participant groups; this is not a large evidence base
Population Generally healthy adults
Outcomes Deliberately not summarised here — no authorised claim exists, and characterising outcomes as benefits would be making one

If you want to read the primary studies, search PubMed for "pyrroloquinoline quinone" and filter to human trials. We'd rather point you at the source than paraphrase it into something that sounds like a claim. Our full citation list is on the research references page.

Why we're being this restrictive

Because most of the category isn't. Look at UK PQQ listings and you'll routinely find "cellular energy", "mitochondrial support", "brain health" and "healthy ageing" — none of which are authorised for PQQ. A brand willing to make unauthorised claims on the front of a pack is telling you something about how it handles the rest of its labelling, including the parts you can't easily check.

The Range

Our PQQ products.

Vitality PQQ 20mg capsules, PQQ disodium salt, 60 vegan capsules
Vitality PQQ 20mg capsules three month supply, 180 capsules

PQQ disodium salt, 20mg per serving — dosed at the GB authorised maximum. 60 vegan capsules (30-day supply) or 180 capsules (90-day supply). UK manufactured, independently batch tested. Not for use by pregnant or breastfeeding women.

Next step

Choosing between PQQ products?

Our buying guide applies the 20mg ceiling and the labelling checks on this page to real products, and shows how to spot a PQQ supplement built for a different market.

FAQs

Common questions.

Pyrroloquinoline quinone — a small quinone compound, also called methoxatin, first described in the late 1970s as a redox cofactor in certain bacterial enzymes. That's a role broadly comparable to what NAD and FAD do elsewhere in biology. It occurs in soil and in trace amounts in plant foods. In supplements it's supplied as PQQ disodium salt, a regulated novel food in Great Britain and the EU.
Genuinely unsettled — and worth being straight about. A 2003 Nature paper proposed a vitamin-like role for PQQ in mammals. Later work disputed it, arguing no specific mammalian enzyme requiring PQQ had been demonstrated and no true deficiency state established. The question isn't resolved either way. The regulatory position is clear though: PQQ is not classified as a vitamin in UK food law. It's a novel food, has no NRV, and carries no authorised claims.
Small amounts in natto, kiwi fruit, green tea, parsley, green peppers and cocoa, among others. The quantities are very small — estimated dietary intake is roughly 0.1 to 1.0mg per day, against a 20mg supplemental ceiling. That gap is the practical reason supplemental PQQ exists, and it's why "found in kiwi fruit" doesn't tell you much.
By bacterial fermentation, not plant extraction — plants contain far too little to be practical. Certain bacteria produce PQQ in normal metabolism; it's harvested and purified from that, then supplied as PQQ disodium salt, which is more stable than the free acid and is the form named in the GB and EU authorisation.
An authorised novel food, with conditions. The two that matter most: a maximum permitted daily intake of 20mg for adults, and the exclusion of pregnant and breastfeeding women from the authorised population. There are no authorised UK or EU health claims for PQQ, so no product may lawfully describe what it does.
It's the maximum daily intake the novel food authorisation permits for adults. Novel food authorisations set the conditions under which an ingredient may be sold, including maximum intakes. The unusual consequence is that dose comparison in this category is capped — a UK product at 40mg or 60mg hasn't been formulated to the GB authorisation, and the bigger number tells you which market it was built for, not that it's better. More in our PQQ buying guide.
Small human studies, generally around 20mg per day, over a few weeks to a few months, in healthy adults. Because no authorised health claims exist for PQQ, we describe study design rather than characterising outcomes as benefits — doing the latter would be making a claim. Search PubMed for "pyrroloquinoline quinone" and filter to human trials to read the primary work.
No. The novel food authorisation excludes pregnant and breastfeeding women — an exclusion, not a general precaution. PQQ supplements are also not intended for children. If you take medication or are under medical care, speak to a healthcare professional first, follow the pack directions and don't exceed the stated daily amount.
No — different compounds, different chemistry, different regulatory positions. CoQ10 (ubiquinone) is a fat-soluble quinone found in human tissue; its reduced form is ubiquinol. PQQ is a small water-soluble quinone originally characterised as a bacterial cofactor, regulated in GB as a novel food with a 20mg ceiling. They're often sold together but aren't interchangeable, and neither carries the authorised UK claims marketing often implies. See PQQ vs CoQ10.
Further Reading

Keep going.

About this guide

Last reviewed 17 August 2026 by the Vitality Supplements Editorial Team, written to our published editorial standards and quality & testing policy. We are a UK supplement manufacturer and we sell PQQ, which we disclose openly. Two editorial decisions worth naming: we have left the "is PQQ a vitamin" question unresolved because it genuinely is, rather than picking whichever answer suits a supplement seller; and we have described the human research by study design only — participants, dose, duration — without characterising outcomes, because no authorised health claim exists for PQQ and summarising outcomes as benefits would be making one. Where we would otherwise be tempted to summarise, we point you to the primary literature instead.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Do not exceed the stated recommended daily dose. PQQ disodium salt is a regulated novel food; the maximum permitted daily intake is 20mg for adults, and the authorised population excludes pregnant and breastfeeding women — PQQ is not for use by pregnant or breastfeeding women. Not suitable for children. There are no authorised UK or EU health claims for PQQ, and no medicinal, disease, energy, mitochondrial, cognitive or anti-ageing claims are made on this page. If you are taking medication or under medical care, consult a healthcare professional before use. This page is general information, not medical advice, and is not intended to diagnose, treat or prevent any condition. Every Vitality batch is independently tested. UK manufactured. Free UK delivery. 60-day satisfaction guarantee on first purchase. Certificate of Analysis available on request. See our full disclaimer · Privacy · Terms · info@vitality-supplements.co.uk