Coenzyme Q10 and mental fatigue: grade C

Limited evidence. Direction: Benefit.

C LimitedSubjective outcome only

Educational guidance, not medical advice

Why this grade

Rubric condition met: The rubric cap: the pooled estimate mixes healthy and clinical populations with no healthy-only estimate (C)

The trials used general fatigue scales mixing physical and mental fatigue, not mental-fatigue measures specifically. A 2022 meta-analysis of 13 RCTs (1,126 participants) found lower fatigue scores with CoQ10 than placebo (Hedges' g -0.398), with the same direction in healthy and diseased participants but no separate healthy-only estimate. The only healthy-volunteer trial cited is a small crossover with an unread erratum, and a 2026 meta-analysis of 2 trials in people with depression found no significant fatigue benefit.

How we grade evidence

Studies this grade rests on

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

Study	Year	Design	Participants	Result
Mizuno 2008	2008	crossover RCT	17	result not recorded
Mehrabani 2019	2019	meta-analysis	not recorded	result not recorded
Tsai 2022	2022	meta-analysis	1126	result not recorded
Magalh 2026	2026	meta-analysis	474	result not recorded

Effects of Coenzyme Q10 Supplementation on Depressive Symptoms and Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Magalhães PLM, da Silva AMP, Maximiano MLB. Effects of Coenzyme Q10 Supplementation on Depressive Symptoms and Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials J Clin Psychopharmacol, 2026. PMID 41294251

Result not recorded

Design: Systematic review and meta-analysis of 5 RCTs (fatigue pooled from 2)
Sample: n = 474
Population: Patients with depression, primary or alongside medical illness (clinical population)
Funding: Funding: not stated in the PubMed or Crossref record; full text not read.

Effect of coenzyme Q10 supplementation on fatigue: A systematic review of interventional studies.

Mehrabani S, Askari G, Miraghajani M. Effect of coenzyme Q10 supplementation on fatigue: A systematic review of interventional studies Complement Ther Med, 2019. PMID 30935528

Result not recorded

Design: Systematic review of 16 interventional studies (no meta-analysis)
Population: Adolescents and adults: healthy people and people with fibromyalgia, statin-related fatigue, multiple sclerosis or end-stage heart failure
Funding: Funding: not stated in the PubMed or Crossref record; full text not read.

Antifatigue effects of coenzyme Q10 during physical fatigue.

Mizuno K, Tanaka M, Nozaki S. Antifatigue effects of coenzyme Q10 during physical fatigue Nutrition, 2008. PMID 18272335

Result not recorded

Design: Double-blind, placebo-controlled, three-way crossover RCT
Sample: n = 17
Population: Healthy volunteers
Funding: Funding: not stated in the PubMed or Crossref record; full text not read.

Effectiveness of Coenzyme Q10 Supplementation for Reducing Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Tsai IC, Hsu CW, Chang CH. Effectiveness of Coenzyme Q10 Supplementation for Reducing Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Front Pharmacol, 2022. PMID 36091835

Result not recorded

Design: Systematic review and meta-analysis of 13 RCTs
Sample: n = 1,126
Population: Healthy and diseased participants pooled (mixed population; no healthy-only estimate in abstract)
Funding: Ministry of Science and Technology (Crossref funder record)

Search and history

Search (November 11, 2026): (coenzyme Q10[ti] OR CoQ10[ti] OR ubiquinol[ti] OR ubiquinone[ti]) AND (fatigue[tiab]) AND (meta-analysis[pt] OR systematic review[pt])

November 12, 2026 Graded C (proposed): Proposed in the monograph draft
November 13, 2026 C to C (approved): Editor sign-off November 13, 2026: grade matches the editor-approved final page