Key findings from detailed records
In adults with mild fatigue, a 12-week trial of ubiquinol 100 or 150 mg/day reported improvements in selected post-task fatigue and sleepiness ratings versus placebo. We examine this alongside the separate Q-SYMBIO heart-failure trial, keeping populations and CoQ10 forms distinct. PMID 32498248
KNOWLEDGE RECORD
- Category
- Metabolism and cellular function
- Last Reviewed
Names and related search termsCoQ10 and ubiquinol / Coenzyme Q10 / Ubiquinol / Ubiquinol / Coenzyme Q10
Study type: human intervention study.
OUTCOME-SPECIFIC EVIDENCE
Scientific Evidence Profile
Assessment pending
An outcome-specific assessment has not yet been completed. This is not a finding that the ingredient is ineffective. The study records below remain available.
This profile concerns the stated outcome and population, not the ingredient as a whole. It is not a probability of benefit, a safety rating, a product efficacy rating or an indication of product adoption.
How we assess evidenceIngredient Profile
- What is it?
- Coenzyme Q10 belongs to the quinone family. Its long side chain contains ten isoprenoid units—the origin of “10” in the name. [1]
Sources for this profile
Compound properties and formulation properties are different. These sources do not establish the efficacy of a finished supplement.
- PubChem — Coenzyme Q10 (CID 5281915) Chemical identity reference. Maintained by NCBI, U.S. National Library of Medicine. Database record; not a clinical trial.
Profile sources checked:
Read the evidence in context
- Evidence: what was measured in the stated population or experimental model.
- Inference: an interpretation connecting findings; its applicability depends on the study conditions.
- Hypothesis: a proposed explanation or effect that remains to be tested.
Why It Matters #
CoQ10 participates in energy transfer, while human trials ask whether supplementation changes fatigue or clinical outcomes. The ubiquinol fatigue trial and Q-SYMBIO answer different questions.
What Was Studied #
71 randomized; 62 analyzed. Otherwise healthy adults with mild fatigue lasting 1–6 months.
Ubiquinol 100 or 150 mg/day versus placebo · 12 weeks
What Was Found #
Both doses improved selected post-task fatigue and sleepiness ratings versus placebo. At 150 mg, additional relaxation and oxidative-stress measures improved. PMID 32498248
What the Evidence Means #
Small trial with post-randomization exclusions and many outcomes/time points. ATP production was not directly measured.
What We Can Learn #
The ubiquinol trial asks about everyday fatigue; Q-SYMBIO asks about adding CoQ10 to heart-failure treatment. Together they show why form, population and endpoint must travel with a result.
What Remains Unknown #
Further questions include reproducibility across populations and formulations, and the long-term balance of benefits and harms. Use the literature map as a starting point for these questions.
LITERATURE MAP / 12 PAPERS
Compare papers by conditions and findings.
A literature map covering different populations, outcomes and formulations. Read alongside detailed records to avoid treating one trial as the conclusion for an entire ingredient.
Initial selection: 2026-09-21; human-study additions: 2026-10-11. Editorial selection spans populations and research questions. The source-review scope is recorded per study; this is not a systematic review.
12 RECORDS
A dash marks fields outside the bibliographic record. Use detailed records to compare findings and design records to connect mechanisms.
| Paper and topic | Study conditions | Findings and scope |
|---|---|---|
| Ubiquinol-10 Intake Is Effective in Relieving Mild Fatigue in Healthy Individuals. | 71 randomized; 62 analyzed. Otherwise healthy adults with mild fatigue lasting 1–6 months. · Ubiquinol 100 or 150 mg/day versus placebo · 12 weeks · Fatigue/sleepiness after cognitive tasks, autonomic measures and oxidative-stress markers | Both doses improved selected post-task fatigue and sleepiness ratings versus placebo. At 150 mg, additional relaxation and oxidative-stress measures improved. Explore the research |
| Mechanism and designTreatment of CoQ(10) deficient fibroblasts with ubiquinone, CoQ analogs, and vitamin C: time- and compound-dependent effectsPMID 20689595 # | Study conditions Human-derived cells / CoQ and ATP — | Findings and scope Supplementation of CoQ10-deficient fibroblasts with CoQ10 improved ATP levels and the ATP/ADP ratio after one week. This informs the focus on the CoQ pool supporting electron transport. A study of ubiquinone in cultured cells, distinct from an oral trial of ubiquinol 100 mg. |
| Safety and tolerabilityThe effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial.PMID 25282031 # | Study conditions Q-SYMBIO: Randomized, double-blind, placebo-controlled trial
| Findings and scope Major events over two years occurred in 15% versus 26%; HR 0.50 (95% CI 0.32–0.80). Short-term measures did not change significantly. View findings and limitations |
| Effects of coenzyme Q10 in early Parkinson disease: evidence of slowing of the functional decline.PMID 12374491 # | Study conditions — | Findings and scope — Open original paper |
| Efficacy of coenzyme Q10 in migraine prophylaxis: a randomized controlled trial.PMID 15728298 # | Study conditions — | Findings and scope — Open original paper |
| Coenzyme Q10 improves blood pressure and glycaemic control: a controlled trial in subjects with type 2 diabetes.PMID 12428181 # | Study conditions — | Findings and scope — Open original paper |
| Effects of coenzyme Q10 supplementation (300 mg/day) on antioxidation and anti-inflammation in coronary artery disease patients during statins therapy: a randomized, placebo-controlled trial.PMID 24192015 # | Study conditions — | Findings and scope — Open original paper |
| Efficacy of coenzyme Q10 on semen parameters, sperm function and reproductive hormones in infertile men.PMID 19447425 # | Study conditions — | Findings and scope — Open original paper |
| Decreases in serum ubiquinone concentrations do not result in reduced levels in muscle tissue during short-term simvastatin treatment in humans.PMID 7828383 # | Study conditions — | Findings and scope — Open original paper |
| Coenzyme Q10 as an adjunctive in the treatment of chronic congestive heart failure. The Q10 Study Group.PMID 9420639 # | Study conditions — | Findings and scope — Open original paper |
| Antifatigue effects of coenzyme Q10 during physical fatigue.PMID 18272335 # | Study conditions — | Findings and scope — Open original paper |
| A randomized clinical trial of high-dosage coenzyme Q10 in early Parkinson disease: no evidence of benefit.PMID 24664227 # | Study conditions — | Findings and scope — Open original paper |
No papers match. Change the search conditions.
The literature map is an index of research questions and references. Individual assessment of results, doses, funding and COI is limited to the detailed study records. Related reports from the same trial may be included; paper counts are not counts of independent trials.
Explore the research Study Records
Listed doses describe study conditions, not recommended intake.
Ubiquinol-10 Intake Is Effective in Relieving Mild Fatigue in Healthy Individuals.
PMID 32498248DOI: 10.3390/nu12061640
- Authors
- Mizuno K, Sasaki AT, Watanabe K, Watanabe Y.
- Journal
- Nutrients
- Publication year
- 2020
- Study design
- Randomized, double-blind, placebo-controlled trial
- Participants
- 71 randomized; 62 analyzed. Otherwise healthy adults with mild fatigue lasting 1–6 months.
- Dose and intervention
- Ubiquinol 100 or 150 mg/day versus placebo
- Duration
- 12 weeks
- Outcomes and their role in the study
- Fatigue/sleepiness after cognitive tasks, autonomic measures and oxidative-stress markers
- Findings
- Both doses improved selected post-task fatigue and sleepiness ratings versus placebo. At 150 mg, additional relaxation and oxidative-stress measures improved.
- Limitations
- Small trial with post-randomization exclusions and many outcomes/time points. ATP production was not directly measured.
- Funding
- Kaneka funded the study, with partial support from the JST/RIKEN Compass to Healthy Life program.
- Conflict of Interest
- Watanabe received study funding from Kaneka; other authors declared no conflicts. The authors reported no sponsor role in study design, analysis or publication decisions.
- Scope of source review
- Methods, results and funding/COI sections of the public full text reviewed on 2026-10-11.
The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial.
PubMed 25282031DOI: 10.1016/j.jchf.2014.06.008
- Authors
- Mortensen SA, Rosenfeldt F, Kumar A, Dolliner P, Filipiak KJ, Pella D, Alehagen U, Steurer G, Littarru GP, Q-SYMBIO Study Investigators.
- Journal
- JACC. Heart failure
- Publication year
- 2014
- Study design
- Q-SYMBIO: Randomized, double-blind, placebo-controlled trial
- Participants
- 420 patients with moderate to severe chronic heart failure
- Dose and intervention
- Ubiquinone (oxidized CoQ10), 100 mg three times daily, added to standard heart-failure treatment.
- Duration
- 2 years, with short-term assessment at 16 weeks.
- Outcomes and their role in the study
- Short-term: NYHA class, six-minute walk and NT-proBNP. Long-term: major cardiovascular events.
- Findings
- Major events over two years occurred in 15% versus 26%; HR 0.50 (95% CI 0.32–0.80). Short-term measures did not change significantly.
- Limitations
- The heart-failure trial concerns adjunctive treatment with the studied CoQ10 form. It does not establish effects in healthy people or superiority of another CoQ10 form.
- Funding
- Partial support from the International Coenzyme Q10 Association, Pharma Nord and Kaneka.
- Conflict of Interest
- The authors reported no relationships relevant to the paper to disclose. Industry support is disclosed separately in Funding.
- Scope of source review
- Original article methods, endpoints and disclosures checked on 2026-10-24; formulation also cross-checked against the trial website.
Cite this page
LÍFSVARÐA. Ubiquinol and CoQ10: fatigue, energy biology and human evidence / Updated 2026-10-24
https://lifsvarda.com/knowledge/coenzyme-q10/Edited by LÍFSVARÐA (product brand).Editorial policy
Safety and interactions
CoQ10 can interact with warfarin and insulin, and may be incompatible with some cancer treatments. Check use with the clinician managing these treatments. Digestive upset or insomnia can occur.
Sources and updates
- Ubiquinol-10 Intake Is Effective in Relieving Mild Fatigue in Healthy Individuals.
- Mortensen SA, Rosenfeldt F, Kumar A, Dolliner P, Filipiak KJ, Pella D, Alehagen U, Steurer G, Littarru GP, Q-SYMBIO Study Investigators. (2014). The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial.Original article methods, endpoints and disclosures checked on 2026-10-24; formulation also cross-checked against the trial website.
2026-10-11: Human-study coverage, findings and comparisons reviewed. Source-review scope is stated for each study.