A small redox-active quinone found in trace amounts in foods such as fermented soy, kiwifruit and human milk. Supplements use the synthetic disodium salt.
PQQ is sold on a mitochondrial biogenesis story built almost entirely on rodent and cell work: it activates PGC-1α signalling in cultured cells and increases mitochondrial number in mice. The human literature is a handful of small, short studies, several funded by the ingredient manufacturer, using self-reported sleep, fatigue and cognition as outcomes. There is no long-term human safety data at supplemental doses, and the compound is not a vitamin despite occasional claims to that effect — a proposal that PQQ was a new B vitamin was made in 2003 and subsequently retracted from the scientific record.
Sold as
Capsule, Softgel (often combined with CoQ10)
Standardised to
Milligrams of PQQ disodium salt — a product without this marker may not resemble what was studied.
Regulation: PQQ disodium salt was authorised in the European Union as a novel food, with restrictions on the population it may be sold to and a maximum daily amount. In the US it is a dietary supplement with no pre-market efficacy review.
What the research used
The amounts, forms and durations published trials of PQQ (pyrroloquinoline quinone) actually administered.
These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.
Studied for Small human studies of fatigue and sleep
20 mg
Not enough
Capsule, daily · 8 weeks
The most commonly used dose in the small Japanese studies that underpin the marketing. Sample sizes are in the tens and several were manufacturer-funded.
Studied for Cognition and inflammatory markers
10–40 mg
Not enough
Capsule, daily · 4–12 weeks
Dose range across the handful of published trials. There is no established human dose for PQQ and the upper end has not been studied for long-term safety.
This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.
When it was taken
Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.
None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.
🕐Any time
Not enough
No timing comparison has been published. Products are usually taken in the morning by convention, on the grounds that a compound marketed for energy should be taken early.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.
The evidence in depth
Best supported: Not enough
What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.
Two small Japanese trials reported improvements on selected cognitive subtests. They are underpowered, industry-linked and have not been independently replicated.
Not enough evidence. Not enough human research to say anything useful yet.
The mitochondrial biogenesis evidence is from cells and rodents. Human studies are too few and too small to establish an effect on fatigue or energy metabolism.
What may be going on: PQQ influences PGC-1α and CREB signalling in cultured cells, pathways associated with mitochondrial replication. Whether supplemental PQQ reaches human tissue in amounts that do this is unknown.
Not enough evidence. Not enough human research to say anything useful yet.
A single small open study reported improved sleep questionnaire scores. That is not a basis for a sleep claim.
Not enough evidence. Not enough human research to say anything useful yet.
No source is attached to this association yet, so it is rated not enough evidenceby default. It is listed because people commonly ask about it — not because there is evidence for it.
Things to know
Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.
Worth knowing
Long-term human safety is not established
The published human exposure is weeks, in small numbers of people. Rodent work at high doses has reported kidney effects, and the European novel-food authorisation came with population restrictions and an intake ceiling for that reason.
Avoid
Not studied in pregnancy or childhood
There are no trials in pregnancy, breastfeeding or children. The European authorisation explicitly excludes some of these groups, which is a reasonable default position.
Worth knowing
The "new vitamin" claim is wrong
A 2003 paper proposing PQQ as a novel B vitamin was withdrawn, and PQQ has no established essential role in human nutrition. Marketing that describes it as a vitamin is repeating a retracted claim.
Too much
Headache and stomach upset reported
The small trials report occasional headache, sleepiness and gastrointestinal discomfort, more often at the higher doses. Nothing serious has been reported, but the total number of people studied is small enough that rare effects would not have been seen.
In the food catalogue
The whole-food form, where one exists. The evidence for a concentrated extract rarely transfers to the food, or the other way round — these are cross-links, not equivalents.