PQQ for Cognitive Function
A couple of small Japanese trials report cognitive benefits; independent replication is missing.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- Studied at 20 mg/day, sometimes with 300 mg CoQ10; cognitive benefits are not established
- Expected timeframe
- Not established
Protocol
- form
- PQQ disodium salt
- duration
- Trials ran 8-12 weeks
- co factor
- Evidence is insufficient. The cognitive claims rest on a small number of Japanese studies, mostly published in low-profile journals with limited methodological detail. One frequently cited study reported improvements in memory and attention measures in middle-aged and older adults at 20 mg/day, with greater effect when combined with 300 mg CoQ10; another reported improved cerebral blood flow. Sample sizes were small, blinding and randomisation are inadequately described, several were industry-funded, and there has been no independent replication in a well-powered trial. The mechanistic rationale involving mitochondrial biogenesis and NGF stimulation is drawn from cell and animal work.
- titration
- Not applicable - no dose has been shown to reliably improve cognition
- starting dose
- Not established. Trials used 20 mg/day PQQ, in one Japanese study combined with 300 mg/day CoQ10
Evidence
What the studies say
Effect of Dietary Pyrroloquinoline Quinone Disodium Salt on Cognitive Function in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study
Shiojima Y, Takahashi M, Takahashi R
PQQ supplementation over 12 weeks improved composite memory and verbal memory scores relative to placebo in healthy adults.
Pyrroloquinoline quinone disodium salt improves brain function in both younger and older adults
Tamakoshi M, Suzuki T, Nishihara E
Twelve weeks of PQQ improved cognitive flexibility and processing speed measures in both younger and older adults.
Safety
Caveats
The cognitive evidence for PQQ is weaker than its marketing implies - small, largely unreplicated, often industry-linked studies do not establish an effect. For cognitive health, the interventions with real evidence are physical exercise, sleep, treating hearing loss, controlling blood pressure and diabetes in midlife, limiting alcohol, not smoking and social engagement. Progressive memory problems or cognitive change affecting daily function need medical assessment, since B12 deficiency, hypothyroidism, depression, sleep apnoea and anticholinergic medication burden are common reversible contributors. Safety of PQQ: the human safety database is thin - trials have been short and small, so long-term safety is unknown. Reported effects at 20-40 mg/day include headache, fatigue and sleep disturbance. There is no established upper intake level, and a rodent study showed kidney effects at very high doses, so do not exceed the 20 mg/day studied. Avoid in pregnancy and breastfeeding, as no safety data exist. Drug interactions are undocumented rather than excluded. If combining with CoQ10, note that CoQ10 can reduce warfarin effect through its structural similarity to vitamin K, which is a real interaction worth flagging.
Less likely to help if
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