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PQQ, short for pyrroloquinoline quinone, is a small molecule first identified as a helper compound for bacterial enzymes and now sold as a supplement marketed for energy, focus and cell health. The short answer on evidence: most PQQ research has been done in animals and cells, the human trials are small and several were run by companies that make PQQ, and a 2003 claim that PQQ is a vitamin did not hold up. Here is what PQQ is, what studies in people found, its regulatory status and the safety gaps.
Peptide Labs sells no PQQ supplements, and none of the labels in our catalog list it. This article is general information, not medical advice.
Key Takeaways
- PQQ is a redox-active compound first known as a cofactor for bacterial enzymes; small amounts occur in foods.
- It is not a recognized vitamin; a 2003 vitamin proposal could not be reproduced by another lab.
- Human trials are small, short and often funded or run by PQQ manufacturers.
- FDA has received several GRAS notices for PQQ disodium salt and responded with no questions; that is about food use, not health effects.
- EFSA judged one PQQ ingredient safe for healthy adults but excluded pregnant and breastfeeding women.
What is PQQ?
Pyrroloquinoline quinone belongs to a family of compounds called quinones that can accept and donate electrons. A 2009 review by Rucker and colleagues at the University of California, Davis, notes that PQQ was first recognized as an enzyme cofactor in bacteria and also acts as a plant growth factor, so people and animals are exposed to small amounts through food.
Supplements usually contain PQQ disodium salt made by bacterial fermentation. The European Food Safety Authority (EFSA) describes one such ingredient, sold as BioPQQ, as produced by fermentation with the bacterium Hyphomicrobium denitrificans and purified.
Is PQQ a vitamin?
No. In 2003 two Japanese researchers proposed in Nature that PQQ was a new vitamin, based on changes in lysine metabolism in PQQ-deprived mice. In 2005 a UC Davis team reported in the same journal that it could not reproduce those findings and that the results called the vitamin label into question. The 2009 review states plainly that PQQ is not currently viewed as a vitamin, and no official intake recommendation exists for it.
PQQ benefits: what human studies show
Most claimed PQQ benefits, such as making new mitochondria (the energy-producing parts of cells), come from animal and cell research. Human studies are few. The table summarizes the ones we checked; none is large enough to show that PQQ produces lasting health effects.
| Study | Who and what | Reported finding | Limits |
|---|---|---|---|
| Harris et al. 2013 | 10 adults, crossover, about three days | Lower CRP and IL-6 inflammation markers; routine blood tests unchanged | Very small, very short |
| Shiojima et al. 2022 | 64 healthy Japanese adults aged 40 to 79, 12 weeks | Better scores on several computerized memory and attention tests vs placebo | Authors from the product maker; 58 completed |
| Tamakoshi et al. 2023 | Adults aged 20 to 65, 12 weeks | Some memory measures improved | Authors from the BioPQQ maker |
| Baltic et al. 2024 | 34 older adults with mild memory decline, 6 weeks, PQQ plus hydrogen mix | Primary marker (BDNF) not different from placebo; one orientation score improved | Mixed product, small sample |
| Zhao et al. 2026 | 60 adults, single intake before a treadmill test | One body-awareness questionnaire score improved | Single session, self-reported outcome |
The pattern is typical of an early-stage supplement: small studies, short durations, many different outcomes measured, and a few positive results. Industry funding does not make a study wrong, but it is a reason to wait for independent replication. None of these trials tested PQQ as a way to manage any disease, and it should not replace care from a clinician.
PQQ and other mitochondria supplements
PQQ is often sold in combination with CoQ10, NAD precursors and alpha-lipoic acid. Each has its own evidence and safety profile; see our guides to CoQ10, NMN and alpha-lipoic acid. Combination products make it harder to know which ingredient, if any, caused an effect.
Is PQQ legal? Regulatory status
In the US, PQQ is sold as a dietary supplement ingredient, and supplements are not FDA-approved before sale. The FDA GRAS Notice Inventory lists several notices for PQQ disodium salt. The first was closed on August 18, 2016 with FDA responding that it had no questions, and later notices received the same response, most recently in 2023. A no-questions letter means FDA did not object to the company’s conclusion that the ingredient is generally recognized as safe for specific food uses. It does not mean FDA has evaluated any health benefit.
In Europe, EFSA concluded in 2017 that PQQ disodium salt was safe as a novel food under the intended conditions of use in food supplements for healthy adults, excluding pregnant and breastfeeding women. EFSA also noted that information on how PQQ is absorbed and handled by the body in animals and humans is limited.
PQQ side effects and safety
- Limited human data: the trials above reported few or no adverse events, but they were small and short, so rare or long-term effects would not show up.
- Pregnancy and breastfeeding: EFSA’s safety conclusion excluded these groups; avoid PQQ unless a clinician advises otherwise.
- Children: safety has not been established.
- Medicines: interaction data are scarce. Share every supplement with your pharmacist, especially before surgery or if you take several prescriptions.
- Blends: PQQ often comes with stimulants or other active ingredients, which bring their own side effects.
How to evaluate a PQQ supplement
If you are considering a PQQ supplement, check the Supplement Facts panel for the form (PQQ disodium salt is the ingredient covered by the FDA notices and EFSA opinion), any branded ingredient name, everything else in the blend, and a third-party testing seal; see our third-party tested supplements guide. Be skeptical of anti-aging or energy promises, which go well beyond the evidence. Our resveratrol guide covers a similar case, and our zinc picolinate guide shows how one small study can drive years of marketing.
Questions to ask before trying PQQ
- What do I hope it will do, and is there human evidence for that specific outcome, or only animal data?
- Were the studies behind the product independent, or run by the company that sells the ingredient?
- What else is in the capsule, and do any of those ingredients interact with my medicines?
- Am I pregnant, breastfeeding or planning a pregnancy? If so, EFSA’s safety conclusion did not cover me.
- Would sleep, activity or a review of my current medicines address the reason I feel tired or unfocused?
Ongoing fatigue, memory changes or trouble concentrating can have many causes, from sleep problems and low iron to thyroid conditions and medicine side effects. A clinician can look for those causes before you spend months on an unproven supplement.
Frequently Asked Questions
What is PQQ?
Pyrroloquinoline quinone, a compound first known as a helper for bacterial enzymes. It occurs in small amounts in foods and is sold as a supplement.
What are the proven PQQ benefits?
None are proven. Small human studies reported changes in inflammation markers and cognitive test scores, but they were short and often industry-funded.
Is PQQ a vitamin?
No. A 2003 proposal was not reproduced by another lab, and researchers state it is not currently viewed as a vitamin.
Is a PQQ supplement safe?
Short studies reported few adverse events, but long-term data are lacking. EFSA’s safety opinion excluded pregnant and breastfeeding women.
What are PQQ side effects?
Small trials reported few problems, but they were too short to rule out rare or long-term effects. Blends may add side effects from other ingredients.
Is PQQ FDA approved?
No supplement is FDA-approved. FDA had no questions about several GRAS notices for PQQ disodium salt in food, which is not a health claim review.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines or are pregnant. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: CoQ10 Benefits: What Studies Show, Statins, Side Effects and Forms, NMN Supplement: FDA Status, Research and Side Effects, Third Party Tested Supplements: What USP, NSF and Other Seals Mean.