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PQQ (pyrroloquinoline quinone) and endurance performance: grade C

Limited evidence. Direction: No effect.

C LimitedShort-term only

Educational guidance, not medical advice

Why this grade

Rubric condition met: Two small placebo-controlled RCTs, both null on exercise performance; not adequately sized for N, so C with direction none

In 23 untrained men doing 6 weeks of supervised endurance training, 20 mg/day of PQQ produced no difference from placebo in aerobic performance, although PGC-1alpha protein (a mitochondrial marker) rose. In a four-group trial of 60 male physical education students (placebo, PQQ, NMN or both), a single 20 mg dose of PQQ 60 minutes before a treadmill test did not significantly improve exercise capacity. Both trials are small and short, so under G5 the grade is C with direction none rather than N.

How we grade evidence

Studies this grade rests on

EffectMixedNo effectSize shows participants (n)202020252030RCTZhao 2026, 2026: RCT, n = 60, result not recordedHwang 2020, 2020: RCT, n = 23, result not recorded
each study this grade rests on, by publication year and design. Solid: effect versus the comparator; half-filled: mixed; hollow: no effect; dashed: result not recorded yet. Larger marks had more participants.
Show the numbers
StudyYearDesignParticipantsResult
Hwang 20202020RCT23result not recorded
Zhao 20262026RCT60result not recorded

The effects of pyrroloquinoline quinone and nicotinamide mononucleotide supplementation on interoception following acute exhaustive exercise: a randomised, double-blind, placebo-controlled study.

Zhao C, Wu B, Sui H. The effects of pyrroloquinoline quinone and nicotinamide mononucleotide supplementation on interoception following acute exhaustive exercise: a randomised, double-blind, placebo-controlled study Sci Rep, 2026. PMID 41651893

Result not recorded
Design
Randomized, double-blind, placebo-controlled trial, four groups, single dose 60 minutes before exercise
Sample
n = 60
Population
Male physical education students aged 18 to 28
Funding
Fundamental Research Funds for the Central Universities (2024YDYY002, 2024YJSY001); authors declare no competing interests

Effects of Pyrroloquinoline Quinone (PQQ) Supplementation on Aerobic Exercise Performance and Indices of Mitochondrial Biogenesis in Untrained Men.

Hwang PS, Machek SB, Cardaci TD. Effects of Pyrroloquinoline Quinone (PQQ) Supplementation on Aerobic Exercise Performance and Indices of Mitochondrial Biogenesis in Untrained Men J Am Coll Nutr, 2020. PMID 31860387

Result not recorded
Design
Randomized, placebo-controlled trial with supervised endurance training, 6 weeks
Sample
n = 23
Population
Untrained (non-endurance-trained) men
Funding
Funding: not stated in the PubMed or Crossref record; full text not read.

Search and history

Search (): pyrroloquinoline[tiab] AND (exercise[tiab] OR endurance[tiab] OR muscle[tiab] OR performance[tiab]) AND humans[mh]

  • Graded C (proposed): Proposed in the monograph draft
  • C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page