Limited evidence. Direction: Benefit.
C LimitedIndustry-fundedShort-term only
Rubric condition met: Two small placebo-controlled trials, both run by researchers employed by PQQ makers (C); not B under the rubric because only one trial (n = 64) could be appraised beyond the abstract, and the second reports no sample size or primary outcome in its abstract
In a 12-week randomized, double-blind trial of 64 healthy Japanese adults aged 40 to under 80 who felt more forgetful, 21.5 mg/day of PQQ disodium salt improved composite and verbal memory scores compared with placebo; the trial was funded by Ryusendo, which makes the product tested, and run by its researchers. A second 12-week placebo-controlled trial in adults aged 20 to 65, run by researchers employed by Mitsubishi Gas Chemical, reported better composite and verbal memory, with the memory effect limited to the 41 to 65 age group in stratified analysis; its abstract gives no sample size or primary outcome. A third trial measured visual-spatial function (Touch M), not memory, and is not counted here. With both trials industry-linked, the one with a reported size under 100 participants, and no independent replication, the grade is C rather than B.
| Study | Year | Design | Participants | Result |
|---|---|---|---|---|
| Shiojima 2022 | 2022 | RCT | 64 | result not recorded |
| Tamakoshi 2023 | 2023 | controlled trial | not recorded | result not recorded |
Tamakoshi M, Suzuki T, Nishihara E. Pyrroloquinoline quinone disodium salt improves brain function in both younger and older adults Food Funct, 2023. PMID 36807425
Shiojima Y, Takahashi M, Takahashi R. Effect of Dietary Pyrroloquinoline Quinone Disodium Salt on Cognitive Function in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study J Am Nutr Assoc, 2022. PMID 34415830
Search (): pyrroloquinoline[tiab] AND (cognitive[tiab] OR memory[tiab] OR attention[tiab] OR cognition[tiab])
