PQQ (Pyrroloquinoline Quinone): What the Human Trials Actually Show

By Erin Rose · Updated July 18, 2026 · Methodology

Educational overview — not medical advice. PQQ has no established RDA, upper limit, or long-term (6-month+) human safety data at any dose, and no human trial has tested lifespan, anti-aging, or disease-treatment outcomes. This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

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What PQQ is, and what actually holds up

PQQ (pyrroloquinoline quinone) is a small redox-active compound found in trace amounts in foods like fermented soybeans, parsley, and kiwi, and studied as a supplement primarily for a proposed mitochondrial-biogenesis effect. It is not an essential nutrient — no deficiency state, no RDA, no government-set upper limit — so, like NMN or spermidine, any claimed benefit has to stand on its own evidence rather than on "correcting a shortfall." Twelve verified PMIDs anchor this evidence base, and the honest picture is real but thin and concentrated. Most human trials are small (n=20-41), short (6-12 weeks), run in Japan, and authored by or with researchers affiliated with Mitsubishi Gas Chemical, the maker of BioPQQ™: Itoh/Nakano 2016 (n=41, Stroop-interference attention improved), Nakano 2016 (n=20, NIRS-measured prefrontal blood flow increased), Nakano 2015 (n=29, subgroup-driven LDL reduction), and Tamakoshi 2023 (age-split memory and processing-speed gains). One larger trial, Shiojima 2022 (n=58 completers, the biggest completer-n in this pack), used a different branded ingredient (mnemoPQQ®, not BioPQQ) and its senior co-author is the Chief Scientific Officer of Cepham Inc., a supplement-ingredient company — industry-linked too, and not an independent replication of the BioPQQ cluster. A separate small trial in people with diagnosed mild cognitive impairment, Baltic 2024 (n=34, 6 weeks), used yet another different PQQ form (hydrogen-infused Alpha Hope®) — genuinely interesting, but not the same evidence as the healthy-adult BioPQQ trials and never a dementia-treatment claim.

Does it work? (the honest short version)

Unevenly, and mechanism is doing more marketing work than the human data supports. The mitochondrial-biogenesis story — PQQ activating PGC-1α/CREB to increase mitochondrial density — is real, replicated science, but it comes entirely from a mouse-hepatocyte cell-culture study (Chowanadisai 2010). It has never been measured as the primary outcome of a human PQQ trial in this evidence base. The one human trial that got closest, Hwang 2020 (n=23 untrained men, academic/non-industry), found PGC-1α protein rose significantly in muscle after 6 weeks of PQQ plus endurance training — but produced no additional aerobic-performance or body-composition benefit over training alone. That's the cleanest mechanism-versus-outcome lesson in this pack: a real biomarker moved, and it didn't translate into a measurable functional benefit, even in the one non-industry trial built partly to look for it. Separately, Harris 2013 (UC Davis, n=10, the most independent human data point here) found PQQ lowered inflammatory markers (CRP, IL-6) and altered urinary markers consistent with mitochondrial-related metabolism — interesting, but a biomarker pilot, not a cognitive or clinical outcome. The cognition cluster (Itoh/Nakano, Nakano CBF, Tamakoshi, Shiojima) is where PQQ's evidence is strongest and most consistent — see the full breakdown — but read every trial with its industry affiliation attached.

The buying and safety problem

All four products tracked here disclose PQQ mg directly on the label, so a cost-per-mg comparison is mechanically possible — the real buying distinction is BioPQQ™ (the traceable, trial-tested branded raw material) versus generic PQQ disodium salt (the same molecule, chemically, but with no traceable link to the cited trials). See the full ranking on best PQQ, including why the NOW Foods PQQ+CoQ10 combo is excluded from the clean cost-per-mg table. On safety: every human trial in this evidence base reported PQQ as well tolerated, up to 21.5mg/day for 12 weeks, with no serious adverse events. The "PQQ and kidneys" concern people sometimes raise online traces to a 1989 rat study using intraperitoneal injection — not oral dosing — at a dose/route combination that doesn't represent supplement use (Watanabe 1989). Two more recent, larger, ORAL rat toxicology studies found no-adverse-effect levels of 100mg/kg/day (Nakano 2014, Mitsubishi-affiliated, reversible high-dose kidney changes in females only) and 400mg/kg/day (Liang 2015, an independent Chinese toxicology group, no adverse effects at any dose tested) — margins roughly 300-1,500× the human trial dose. No trial in this pack has run longer than 12 weeks, so there is no long-term (6-month+) human safety data at any dose, and no pregnancy/breastfeeding data exists.

Frequently asked questions

Related guides

• CoQ10 — the mitochondrial-energy supplement PQQ is most often bundled and marketed alongside
• NMN — another mitochondria-adjacent, single-mechanism-marketed ingredient with its own industry-concentration story
• Nicotinamide Riboside — NAD+ reliably rises, but independent functional trials mostly came back null or underpowered
• Magnesium — a nutrient with a genuine deficiency state, unlike PQQ

Sources

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