Improvement in intestinal coenzyme q10 absorption by food intake
Human absorption study directly relevant to food and formulation effects, but it measured pharmacokinetics rather than clinical outcomes and does not compare clock-time dosing.
Coenzyme Q10 · Ubiquinone/ubiquinol · Mitochondrial electron transport and redox research
The evidence base for CoQ10
Coenzyme Q10 (CoQ10) is a lipid-soluble quinone required for mitochondrial electron transport and also participates in cellular redox biology. Supplemental CoQ10 is sold principally as oxidized ubiquinone and reduced ubiquinol, but formulation can materially change exposure, so milligram dose and chemical form should not be treated as interchangeable proxies for bioavailability. The human literature is broad but uneven. Heart-failure trials and meta-analyses provide the strongest clinical-outcome signal, while blood-pressure, migraine, fatigue, metabolic and fertility studies show smaller or population-specific effects. The library now also includes direct evidence on dietary CoQ10, cognition, liver outcomes and hair/scalp research. Other areas are clearly negative or mixed: a large phase III Parkinson trial was stopped for futility, a 2026 cognition RCT raised plasma CoQ10 without improving cognitive outcomes, statin-muscle studies disagree, and exercise studies often show biochemical target engagement without improved performance. This Data Center deliberately includes null results alongside positive studies.
Evidence at a glance
9
Tier 1
59
Tier 2
31
Tier 3
1
Tier 4
Bioavailability and food effects
Miso Soup Consumption Enhances the Bioavailability of the Reduced Form of Supplemental Coenzyme Q10.
Small repeated-measures human food-interaction study directly relevant to early ubiquinol absorption, but short-term, food-specific, and not designed to test clinical outcomes or morning-versus-night timing.
Bioavailability and formulation
Bioavailability of four oral coenzyme Q10 formulations in healthy volunteers
Randomized four-way crossover pharmacokinetic study directly comparing four 100 mg CoQ10 formulations in the same healthy volunteers. It is foundational formulation evidence, although only 10 people were studied and the formulations reflect 1990s technology.
Study on safety and bioavailability of ubiquinol (Kaneka QH) after single and 4-week multiple oral administration to healthy volunteers
Human single- and multiple-dose placebo-controlled safety/pharmacokinetic study establishing short-term ubiquinol exposure and tolerability. Useful for PK/safety, but short duration and complete manufacturer authorship substantially limit independent evidentiary weight.
Comparative Bioavailability of Different Coenzyme Q10 Formulations in Healthy Elderly Individuals
Randomized three-period crossover pharmacokinetic study in older adults directly comparing water-soluble ubiquinone, commercial ubiquinol and standard ubiquinone at the same nominal 100 mg dose. Highly relevant to formulation claims, but single-dose and only 21 participants.
A Randomized, Double-Blind, Two-Treatment, Two-Period, Crossover Study Investigating the Systemic Bioavailability of a Novel Cocrystal Ubiquinol Formulation Compared with a Ubiquinone Formulation in Healthy Adults
Randomized double-blind two-period crossover pharmacokinetic study with complete follow-up and direct head-to-head exposure comparison, but only 12 healthy adults and one proprietary cocrystal ubiquinol formulation under fasting conditions.
A Randomized, Double-Blind, Placebo-Controlled Trial Comparing the Effects of Commercially Available Ubiquinone, Ubiquinol, and Geranylgeraniol Dietary Supplements on Plasma CoQ10 Concentrations
Randomized double-blind placebo-controlled five-arm study in 150 healthy adults comparing commercially available ubiquinone, ubiquinol, geranylgeraniol and combination products over eight weeks. Highly useful for real-world formulation comparisons, but plasma CoQ10—not clinical efficacy—was the primary endpoint.
Sourcedoi:10.1155/jnme/5589963PMID 42807157PMC13617315 Trial registry
Bioavailability and pharmacokinetics
Pharmacokinetic study of deuterium-labelled coenzyme Q10 in man
Small human single-dose pharmacokinetic study useful for absorption timing and half-life, but not for clinical outcomes or morning-versus-night comparisons.
SourcePMID 3781673
Blood pressure
Effects of coenzyme Q10 administration on blood pressure and heart rate in adults: A systematic review and meta-analysis of randomized controlled trials
Current broad meta-analysis of 45 randomized trials; clinically interpretable BP estimates but heterogeneous populations and interventions.
Sourcedoi:10.1016/j.ijcrp.2025.200424PMID 40495903PMC12150111
Dose-Response Effect of Coenzyme Q10 Supplementation on Blood Pressure among Patients with Cardiometabolic Disorders: A GRADE-Assessed Systematic Review and Meta-Analysis of Randomized Controlled Trials
GRADE-assessed dose-response synthesis of 26 randomized trials; evidence was moderate for systolic BP and lower for other outcomes.
Blood pressure and hypertension
Coenzyme Q10 in the treatment of hypertension: a meta-analysis of the clinical trials
Older meta-analysis with a large apparent blood-pressure effect, but the evidence base mixed three randomized trials with a crossover study and eight open-label studies, limiting causal confidence.
Randomized, double-blind, placebo-controlled trial of coenzyme Q10 in isolated systolic hypertension
Randomized double-blind placebo-controlled trial, but small and from an older evidence base in which at least one positive trial was later excluded from a strict Cochrane pooling because of unacceptably high risk of bias.
A randomized, double-blind, placebo-controlled crossover study of coenzyme Q10 therapy in hypertensive patients with the metabolic syndrome
Randomized double-blind placebo-controlled crossover trial using 24-hour ambulatory blood pressure, a clinically stronger measurement than isolated office readings, though the sample was small.
Blood pressure lowering efficacy of coenzyme Q10 for primary hypertension
Rigorous Cochrane review restricted to double-blind randomized placebo-controlled trials of primary hypertension, but only two small trials with 50 participants could be pooled.
Sourcedoi:10.1002/14651858.CD007435.pub3PMID 26935713PMC6486033
The Effects of Coenzyme Q10 Supplementation on Blood Pressures Among Patients with Metabolic Diseases: A Systematic Review and Meta-analysis of Randomized Controlled Trials
Systematic review and meta-analysis of 17 randomized controlled trials in metabolic disease; useful pooled evidence but population and trial heterogeneity limit universal hypertension conclusions.
The effect of CoQ10 supplementation on cardiovascular risk factors in patients with prediabetes and type 2 diabetes mellitus: a grade-assessed systematic review and dose-response meta-analysis
Recent GRADE-assessed systematic review and dose-response meta-analysis of randomized trials in prediabetes and type 2 diabetes; highly relevant to cardiometabolic use but not a pure primary-hypertension population.
Sourcedoi:10.1186/s40360-025-01002-1PMID 42642774PMC13508260
Effects of Coenzyme Q10 Supplementation on Metabolic Indicators in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis
Systematic review and meta-analysis of 16 randomized controlled trials in type 2 diabetes, directly reporting pooled systolic and diastolic blood-pressure effects; interpretation is limited by high heterogeneity and population specificity.
Cancer-related fatigue
A randomized, double-blind, placebo-controlled study of oral coenzyme Q10 to relieve self-reported treatment-related fatigue in newly diagnosed patients with breast cancer
Large randomized double-blind placebo-controlled supportive-care trial with 236 women, 24-week treatment, biochemical adherence confirmation and multiple validated fatigue/QOL instruments. Strong null evidence for standard-dose CoQ10 in this setting, though attrition was substantial and the population had newly diagnosed breast cancer receiving adjuvant therapy.
Sourcedoi:10.1016/j.suponc.2012.03.003PMID 22682875PMC3501550 Trial registry
Cardiovascular disease
Coenzyme Q10 as Adjunctive Therapy for Cardiovascular Disease and Hypertension: A Systematic Review
Systematic review of 14 randomized or crossover studies (1,067 participants) across several cardiovascular conditions, but the underlying trials were heterogeneous, often underpowered for major clinical endpoints, and the authors cautioned against widespread use without further research.
Cardiovascular primary prevention
Co-enzyme Q10 supplementation for the primary prevention of cardiovascular disease
Cochrane systematic review of randomized primary-prevention trials, but only six small short-term RCTs (218 participants) contributed, no trial reported mortality or non-fatal cardiovascular events, and the review judged the evidence underpowered and imprecise.
Sourcedoi:10.1002/14651858.CD010405.pub2PMID 25474484PMC9759150
Chronic kidney disease
Randomized crossover clinical trial of coenzyme Q10 and nicotinamide riboside in chronic kidney disease
Randomized, double-blind, placebo-controlled three-period crossover trial with objective ergometry outcomes and extensive metabolomics/lipidomics. Internal validity is strong for the tested short-term physiology endpoints, but only 25 participants with CKD were studied and treatment lasted six weeks per period.
Sourcedoi:10.1172/jci.insight.167274PMID 37159264PMC10393227
A systematic review for the efficacy of coenzyme Q10 in patients with chronic kidney disease
Systematic review of 12 independent CKD studies represented by 17 publications. Useful for mapping the CKD evidence base and pooled metabolic biomarkers, but cardiovascular outcomes were inconsistent and the main positive findings were surrogate markers rather than kidney-failure or mortality endpoints.
CoQ biosynthesis and deficiency
Biosynthesis, Deficiency, and Supplementation of Coenzyme Q
Peer-reviewed mechanistic and clinical review focused on endogenous CoQ biosynthesis and primary/secondary deficiency; strong contextual source but not an intervention efficacy trial.
CoQ physiology and mechanism
Understanding coenzyme Q
Comprehensive peer-reviewed physiological review synthesizing foundational CoQ biology, biosynthesis and deficiency; authoritative for mechanism but not a clinical efficacy trial.
Sourcedoi:10.1152/physrev.00040.2023PMID 38722242PMC11495197
CoQ status and aging
Coenzyme Q10 serum concentration and redox status in European adults: influence of age, sex, and lipoprotein concentration
Large human cross-sectional observational study of serum CoQ10 status with a small short supplementation substudy; useful for age/redox associations but not proof of age-related tissue deficiency or clinical benefit.
CoQ10 · PCOS · IVF · fertility outcomes
The effect of coenzyme Q10 supplementation on in vitro fertilization outcomes in infertile patients with polycystic ovary syndrome
Recent human IVF cohort with clinically important outcomes, but retrospective nonrandomized design leaves substantial risk of selection bias and residual confounding.
CoQ10 · female fertility · poor ovarian response · ICSI
Coenzyme Q10 Impact on Ovarian Reserve Measures and the Intra-Cytoplasmic Sperm Injection (ICSI) Outcomes in Women with Poor Ovarian Response: A Randomized Controlled Study
Prospective randomized controlled human study directly testing CoQ10 in poor ovarian response, but it was open-label, small, and not powered to establish a live-birth benefit.
Sourcedoi:10.2147/DDDT.S583321PMID 41800295PMC12965276 Trial registry
CoQ10 · female fertility · poor ovarian response · IVF
TEAS, DHEA, CoQ10, and GH for poor ovarian response undergoing IVF-ET: a systematic review and network meta-analysis
Network meta-analysis of 16 randomized trials in poor ovarian response, but treatment rankings rely partly on indirect comparisons and the direct CoQ10 evidence base was limited.
Sourcedoi:10.1186/s12958-023-01119-0PMID 37464357PMC10355041
CoQ10 · male fertility · idiopathic infertility
Efficacy and Safety of Coenzyme Q10 in Idiopathic Male Infertility: A Systematic Review and Meta-Analysis of Randomized Trials
Systematic review and meta-analysis of randomized trials in idiopathic male infertility. Semen outcomes were supported by multiple trials, while pregnancy estimates were based on fewer events and remained imprecise.
CoQ10 · male fertility · semen parameters
Coenzyme Q10 and male infertility: a meta-analysis
Meta-analysis of randomized trials in infertile men, but only three small trials were available and one included Safarinejad trial is now subject to a formal Expression of Concern.
Cognition and brain health
Effect of Ubiquinol on Cognitive Function, Blood Pressure, Arterial Stiffness, and Biomarkers of Oxidative Stress and Inflammation in the Elderly: A Randomized Trial
Randomized placebo-controlled human trial directly testing cognitive outcomes in older adults, with a clearly negative between-group primary cognitive result despite strong plasma CoQ10 target engagement.
Dietary sources
The coenzyme Q10 content of the average Danish diet
Direct food-composition and dietary-intake research useful for quantifying natural CoQ10 exposure, but it is descriptive rather than a clinical efficacy study.
SourcePMID 9129255
Coenzyme Q10 contents in foods and fortification strategies
Comprehensive peer-reviewed review of food CoQ10 content and dietary exposure that is directly useful for nutrition guidance, but it is not a clinical-outcome systematic review.
Dietary sources and bioavailability
Coenzyme Q10 in the diet--daily intake and relative bioavailability
Human dietary-intake and randomized crossover absorption evidence that directly informs food-source and bioavailability questions, but it measures exposure rather than clinical outcomes.
Endothelial function
Effect of Coenzyme Q10 Supplementation on Vascular Endothelial Function: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Updated synthesis of randomized trials with direct endothelial-function measures; sample remains modest and markers other than FMD were not consistently improved.
Effects of coenzyme Q10 on vascular endothelial function in humans: a meta-analysis of randomized controlled trials
Early meta-analysis of randomized human trials with direct vascular-function outcomes, but only five trials and 194 participants.
Sourcedoi:10.1016/j.atherosclerosis.2011.10.027PMID 22088605
Exercise performance
Effect of six weeks ubiquinol supplementation on mitochondrial respiratory function and exercise capacity in healthy males
Modern double-blind randomized placebo-controlled trial with direct skeletal-muscle mitochondrial-respiration measurements and severe-intensity exercise testing in 54 healthy recreationally active men. Strong mechanistic human evidence, but six weeks of dosing and male-only enrollment limit generalizability.
Sourcedoi:10.1007/s00421-026-06275-wPMID 42249931PMC13541835
Coenzyme Q10 supplementation increases blood concentrations but shows limited and inconsistent effects on exercise performance: a systematic review and meta-analysis
Current systematic review/meta-analysis of 24 randomized studies in healthy adults using RoB2 and GRADE. It robustly confirms higher circulating CoQ10 but finds only small, inconsistent and outlier-sensitive exercise-performance effects, with overall certainty very low to low.
Fatigue
Effectiveness of Coenzyme Q10 Supplementation for Reducing Fatigue: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
PRISMA systematic review/meta-analysis of 13 RCTs and 1,126 participants, with RoB2 assessment, sensitivity analyses, subgroup analyses and meta-regression. It supports a modest fatigue signal, but heterogeneity was substantial and populations/scales were diverse.
Coenzyme Q10 as a treatment for fatigue and depression in multiple sclerosis patients: A double blind randomized clinical trial
Randomized double-blind placebo-controlled trial using validated fatigue and depression scales, but only 48 participants were randomized and 45 contributed to the repeated-measures analysis; results are disease-specific and symptom-based.
Female fertility
Pretreatment with coenzyme Q10 improves ovarian response and embryo quality in low-prognosis young women with decreased ovarian reserve: a randomized controlled trial
Prospective randomized controlled IVF/ICSI trial in POSEIDON group 3 women with diminished ovarian reserve. Direct ovarian-response and embryology outcomes are useful, but the control was no pretreatment, 17 randomized women were excluded for low compliance, and live birth was not significantly improved.
Sourcedoi:10.1186/s12958-018-0343-0PMID 29587861PMC5870379 Trial registry
Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? A systematic review and meta-analysis of randomized-controlled trials
Systematic review and meta-analysis restricted to five randomized controlled trials with clinically meaningful ART outcomes. The clinical-pregnancy signal is useful, but only 449 women were included and live-birth and miscarriage estimates remained imprecise and non-significant.
Clinical evidence of coenzyme Q10 pretreatment for women with diminished ovarian reserve undergoing IVF/ICSI: a systematic review and meta-analysis
Recent PRISMA/PROSPERO meta-analysis of six RCTs and 1,529 women with diminished ovarian reserve. Quantitative ART estimates are useful, but every trial lacked blinding, allocation concealment was not reported, and five of six studies used CoQ10 as part of a combination regimen rather than isolated CoQ10.
Sourcedoi:10.1080/07853890.2024.2389469PMID 39129455PMC11321116
Fibromyalgia
Can coenzyme q10 improve clinical and molecular parameters in fibromyalgia?
Randomized double-blind placebo-controlled human trial with both clinical and molecular outcomes, but only 20 fibromyalgia patients and 40 days of treatment. Best treated as pilot/hypothesis-generating evidence rather than a stable efficacy estimate.
Effects of Coenzyme Q10, Tryptophan, and Magnesium Supplementation on Fatigue in Patients with Fibromyalgia - A Randomized Trial
Randomized double-blind placebo-controlled crossover trial with 110 enrolled, but it tested a three-ingredient combination and the prespecified fatigue endpoint was not superior to placebo.
Fibromyalgia and rheumatic disease
Coenzyme Q10 supplementation in rheumatic diseases: A systematic review
Systematic review of 20 human articles, but the underlying rheumatic-disease evidence is small, heterogeneous and dominated by fibromyalgia studies.
Formulation and bioavailability
Ubiquinol is superior to ubiquinone to enhance Coenzyme Q10 status in older men
Randomized double-blind human crossover directly comparing ubiquinol with ubiquinone, but only 10 older men were studied for short treatment periods and the endpoints were circulating CoQ10 status and biomarkers rather than clinical outcomes.
Bioavailability of coenzyme Q10 supplements depends on carrier lipids and solubilization
Double-blind within-subject human crossover pharmacokinetic study comparing seven 100 mg CoQ10 formulations. It directly demonstrates formulation-dependent exposure but included only 14 healthy young adults and did not test clinical outcomes.
Comparison study of plasma coenzyme Q10 levels in healthy subjects supplemented with ubiquinol versus ubiquinone
Direct fixed-sequence human comparison using identical softgel excipients, but only 12 healthy volunteers were studied and ubiquinone was always given before ubiquinol; endpoints were circulating CoQ10 exposure rather than clinical outcomes.
The Plasma Bioavailability of Coenzyme Q10 Absorbed from the Gut and the Oral Mucosa
Small blinded comparative human formulation study with repeated testing of all three products in the same 11 participants. It informs short-term plasma exposure and delivery-route questions but was not a full pharmacokinetic study and did not test clinical outcomes.
Healthy aging and longevity
Cardiovascular mortality and N-terminal-proBNP reduced after combined selenium and coenzyme Q10 supplementation: a 5-year prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens
Prospective randomized double-blind placebo-controlled trial with 443 older adults, long intervention, mortality, biomarker and echocardiographic endpoints. Clinically important randomized evidence, but it tests a fixed selenium-plus-CoQ10 combination in a low-selenium Swedish population, had substantial four-year attrition, and cannot isolate the effect of CoQ10.
Sourcedoi:10.1016/j.ijcard.2012.04.156PMID 22626835 Trial registry
Reduced Cardiovascular Mortality 10 Years after Supplementation with Selenium and Coenzyme Q10 for Four Years: Follow-Up Results of a Prospective Randomized Double-Blind Placebo-Controlled Trial in Elderly Citizens
Ten-year mortality follow-up of the original randomized KiSel-10 cohort with complete mortality ascertainment. The long follow-up is valuable, but treatment stopped after four years, the cohort is small and region-specific, and the original intervention combined selenium with CoQ10.
Sourcedoi:10.1371/journal.pone.0141641PMID 26624886PMC4666408 Trial registry
Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: A validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly
Twelve-year mortality follow-up of the original randomized KiSel-10 cohort with complete registry mortality ascertainment and adjusted Cox modeling. Valuable durability evidence, but it remains the same small combination-intervention cohort and is explicitly hypothesis-generating.
Sourcedoi:10.1371/journal.pone.0193120PMID 29641571PMC5894963 Trial registry
Selenium and coenzyme Q10 improve the systemic redox status while reducing cardiovascular mortality in elderly population-based individuals
Secondary biomarker analysis nested within the randomized KiSel-10 combination trial, with 434 participants measured at baseline and 48 months. Stronger than cross-sectional mechanism data for intervention-related redox change, but cannot isolate CoQ10 and the mortality association with free thiols is observational.
Sourcedoi:10.1016/j.freeradbiomed.2023.04.024PMID 37179031 Trial registry
Heart failure
The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial
Landmark multicenter randomized double-blind placebo-controlled human trial with long-term clinical outcomes in chronic heart failure.
The effect of coenzyme Q10 in patients with congestive heart failure
Randomized double-blind controlled human trial with objective exercise and cardiac-function endpoints, but small sample size.
Sourcedoi:10.7326/0003-4819-132-8-200004180-00006PMID 10766682
Efficacy and safety of coenzyme Q10 in heart failure: a meta-analysis of randomized controlled trials
Large synthesis of randomized heart-failure trials with GRADE assessment; certainty varies by outcome and the underlying trials are heterogeneous.
Sourcedoi:10.1186/s12872-024-04232-zPMID 39462324PMC11515203
Efficacy of coenzyme Q10 in patients with cardiac failure: a meta-analysis of clinical trials
Meta-analysis of 14 randomized trials with clinically important outcomes, but substantial heterogeneity for several measures.
Effect of coenzyme Q10 therapy in patients with congestive heart failure: a long-term multicenter randomized study
Large randomized double-blind 1-year multicenter trial with 641 patients and clinically relevant hospitalization/complication outcomes, but conducted before contemporary heart-failure therapy and reported briefly.
Effect of coenzyme Q10 supplementation on heart failure: a meta-analysis
Meta-analysis of 13 randomized controlled trials evaluating LVEF and NYHA class; informative for cardiac-function surrogates but based largely on small heterogeneous older trials.
Coenzyme Q10 in the Treatment of Heart Failure with Preserved Ejection Fraction: A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial
Randomized double-blind placebo-controlled human pilot trial directly addressing HFpEF, but only 39 participants and four months of treatment.
Effect of coenzyme Q10 on cardiac function and survival in heart failure: an overview of systematic reviews and meta-analyses
Overview of 10 meta-analyses synthesizing cardiac-function and patient-important heart-failure outcomes; useful for evidence consistency but dependent on overlapping underlying trials.
Effect of Coenzyme Q10 Supplementation on Cardiac Function and Quality of Life in Patients with Heart Failure: A Randomized Controlled Trial
Randomized double-blind placebo-controlled 6-month trial with 120 patients on contemporary background therapy and functional/biomarker outcomes; not powered for mortality and has baseline imbalances.
Coenzyme Q10 for heart failure
Cochrane systematic review of randomized controlled trials with formal risk-of-bias and GRADE assessment, directly evaluating patient-important heart-failure outcomes.
Sourcedoi:10.1002/14651858.CD008684.pub3PMID 35608922PMC8092430
Coenzyme Q10 to manage chronic heart failure with a reduced ejection fraction: a systematic review and economic evaluation
Comprehensive NIHR health-technology assessment with systematic review, meta-analysis and economic modeling focused on HFrEF; high methodological value despite substantial concerns about underlying trial bias and applicability.
2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines
Major evidence-based U.S. clinical practice guideline from AHA/ACC/HFSA, directly addressing nutritional supplements and discussing Q-SYMBIO in the heart-failure treatment context.
Inflammation
Efficacy and Optimal Dose of Coenzyme Q10 Supplementation on Inflammation-Related Biomarkers: A GRADE-Assessed Systematic Review and Updated Meta-Analysis of Randomized Controlled Trials
GRADE-assessed meta-analysis of 31 randomized trials; strong biomarker synthesis but not direct evidence of clinical outcomes.
Liver health and NAFLD
Effects of coenzyme Q10 supplementation on lipid profiles and liver enzymes of nonalcoholic fatty liver disease (NAFLD) patients: A systematic review and meta-analysis of randomized controlled trials
Systematic review and meta-analysis restricted to randomized NAFLD trials, but only six studies were available and heterogeneity was high; overall pooled liver-enzyme and lipid effects were not statistically significant.
Male fertility
Coenzyme Q10 treatment in infertile men with idiopathic asthenozoospermia: a placebo-controlled, double-blind randomized trial
Double-blind randomized placebo-controlled male-infertility trial with six months of treatment; sample modest and endpoints were semen parameters rather than live birth.
Coenzyme Q10 improves seminal oxidative defense but does not affect on semen parameters in idiopathic oligoasthenoteratozoospermia: a randomized double-blind, placebo controlled trial
Randomized double-blind placebo-controlled trial with both oxidative and semen endpoints; small sample and null semen-parameter result.
Effects of the reduced form of coenzyme Q10 (ubiquinol) on semen parameters in men with idiopathic infertility: a double-blind, placebo controlled, randomized study
Although designed as a randomized double-blind placebo-controlled trial, the 2012 article is subject to a formal 2023 Expression of Concern from The Journal of Urology. Its reported efficacy estimates should not be used as high-confidence evidence.
Evaluation of monotherapy of Coenzyme Q10, L-carnitine or combined therapy on semen parameters in idiopathic male infertility: A placebo-controlled double blind randomized clinical trial
Four-arm, placebo-controlled double-blind randomized trial with concealed allocation and 200 men randomized. Direct semen and sperm-DNA outcomes are useful, but 26 participants did not complete follow-up and no pregnancy or live-birth outcome was measured.
Sourcedoi:10.1080/20905998.2025.2509424PMID 41509099PMC12777869
Male fertility · dietary supplements · CoQ10
The Effect of Dietary Supplements on Male Infertility in Terms of Pregnancy, Live Birth, and Sperm Parameters: A Systematic Review and Meta-Analysis
Large systematic review of placebo-controlled randomized trials focused on clinically meaningful fertility outcomes, but evidence spans many different supplements and certainty for most outcomes was low or very low.
Metabolic health
Effects of Coenzyme Q10 on Lipid, Glycemic, and Inflammatory Markers in Metabolic Disorders: A Systematic Review and Meta-Analysis
Large 2026 synthesis of 64 randomized trials, useful for effect-size context but pooling heterogeneous metabolic populations.
Migraine
Efficacy of coenzyme Q10 in migraine prophylaxis: a randomized controlled trial
Double-blind randomized placebo-controlled trial with clinically relevant migraine outcomes, but only 42 participants.
Coenzyme Q10 supplementation for prophylaxis in adult patients with migraine-a meta-analysis
Meta-analysis of six migraine studies with 371 participants; supports frequency and duration effects but evidence base remains small.
Sourcedoi:10.1136/bmjopen-2020-039358PMID 33402403PMC7786797
Muscle health and physical capacity
Effects of Coenzyme Q10 Supplementation on Muscle Health and Physical Capacity in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Recent systematic review and meta-analysis restricted to randomized controlled trials with formal risk-of-bias and certainty assessment; key pooled estimates were low or very-low certainty and generally compatible with no clinically meaningful benefit.
NAFLD
Oral coenzyme Q10 supplementation in patients with nonalcoholic fatty liver disease: effects on serum vaspin, chemerin, pentraxin 3, insulin resistance and oxidative stress
Randomized double-blind placebo-controlled human NAFLD trial, but very small and only four weeks long.
Functions of Coenzyme Q10 Supplementation on Liver Enzymes, Markers of Systemic Inflammation, and Adipokines in Patients Affected by Nonalcoholic Fatty Liver Disease: A Double-Blind, Placebo-Controlled, Randomized Clinical Trial
Randomized double-blind placebo-controlled NAFLD trial with 12-week follow-up; sample remains small.
Oxidative stress
Effects of Coenzyme Q10 Supplementation on Biomarkers of Oxidative Stress in Adults: A GRADE-Assessed Systematic Review and Updated Meta-Analysis of Randomized Controlled Trials
GRADE-assessed meta-analysis of 34 randomized trials; useful biomarker evidence but not direct evidence of clinical outcomes.
Parkinson disease
A randomized clinical trial of high-dosage coenzyme Q10 in early Parkinson disease: no evidence of benefit
Large multicenter phase III randomized double-blind placebo-controlled trial with 600 participants and prespecified futility stopping.
Coenzyme Q10 for Patients with Parkinson's Disease: A Systematic Review and Meta-Analysis
Systematic review and meta-analysis of five randomized trials totaling 981 participants, dominated by the large negative QE3 trial.
Periodontal health
Systematic Review on Protocols of Coenzyme Q10 Supplementation in Non-Surgical Periodontitis Therapy
Comprehensive systematic review of randomized periodontal trials, but underlying trials had high or unclear risk of bias, heterogeneous protocols and poor reporting.
Pregnancy and pre-eclampsia
Coenzyme Q10 supplementation during pregnancy reduces the risk of pre-eclampsia
Randomized double-blind placebo-controlled trial with a clinically meaningful pre-eclampsia endpoint in 235 high-risk pregnant women. The finding is notable, but 16.2% were not followed to outcome, detailed maternal/fetal safety reporting was not available in the accessible short report, and independent replication is limited.
Primary CoQ10 deficiency
The efficacy of coenzyme Q10 treatment in alleviating the symptoms of primary coenzyme Q10 deficiency: A systematic review
Systematic review of all reported primary CoQ10-deficiency cases, but the underlying evidence consists of heterogeneous case reports and series rather than randomized trials.
Primary mitochondrial disease
A randomized trial of coenzyme Q10 in mitochondrial disorders
Randomized double-blind crossover trial, but only 30 patients with heterogeneous mitochondrial cytopathies and mostly minor physiologic rather than functional effects.
Beneficial effects of creatine, CoQ10, and lipoic acid in mitochondrial disorders
Randomized double-blind crossover study, but only 16 patients and a three-active-ingredient combination that cannot isolate CoQ10.
Safety and drug interactions
Effect of Coenzyme Q10 and Ginkgo biloba on warfarin dosage in patients on long-term warfarin treatment. A randomized, double-blind, placebo-controlled cross-over trial
Randomized double-blind placebo-controlled crossover trial directly testing CoQ10 during stable warfarin therapy, but only 24 patients were enrolled, 21 completed, treatment periods were four weeks, and warfarin doses were actively adjusted to maintain INR.
SourcePMID 12772396
Safety and pharmacovigilance
Comparative Analysis of L-Carnitine and Coenzyme Q10 Adverse Reaction Reports Using the EudraVigilance Database: Implications for Health and Sports Supplementation
Large real-world pharmacovigilance signal analysis using EudraVigilance spontaneous reports, useful for identifying reporting patterns but unable to estimate incidence or establish causality because exposure denominators, complete clinical context and randomization are absent.
Safety and tolerability
Safety assessment of coenzyme Q10 (Kaneka Q10) in healthy subjects: a double-blind, randomized, placebo-controlled trial
Double-blind randomized placebo-controlled dose-ranging safety trial in 88 healthy adults testing 300–900 mg/day. It provides useful short-term tolerability data with a placebo comparator and laboratory monitoring, but only four weeks of exposure and manufacturer involvement limit long-term safety inference.
Skin health and aging
The effect of dietary intake of coenzyme Q10 on skin parameters and condition: Results of a randomised, placebo-controlled, double-blind study
Randomized double-blind placebo-controlled human study, but only 33 healthy participants and mainly cosmetic surrogate outcomes.
Statin-associated muscle symptoms
Coenzyme Q10 supplementation decreases statin-related mild-to-moderate muscle symptoms: a randomized clinical study
Randomized placebo-controlled trial with patient-reported muscle-pain outcomes, but only 50 participants and 30-day treatment.
A randomized trial of coenzyme Q10 in patients with confirmed statin myopathy
High-internal-validity randomized double-blind trial that first confirmed statin myalgia with blinded statin-placebo crossover before testing ubiquinol.
Sourcedoi:10.1016/j.atherosclerosis.2014.12.016PMID 25545331PMC4298455
Effects of coenzyme Q10 on statin-induced myopathy: a meta-analysis of randomized controlled trials
Meta-analysis of six randomized trials; useful synthesis but based on small heterogeneous studies.
Effects of Coenzyme Q10 on Statin-Induced Myopathy: An Updated Meta-Analysis of Randomized Controlled Trials
Updated meta-analysis of 12 randomized trials; larger than earlier synthesis but symptom scales and trial methods were heterogeneous.
Effect of Coenzyme Q10 on statin-associated myalgia and adherence to statin therapy: A systematic review and meta-analysis
Systematic review of eight randomized trials with seven pooled; later than the positive 2018 synthesis and includes adherence as a clinically relevant endpoint.
Sourcedoi:10.1016/j.atherosclerosis.2020.03.006PMID 32179207
Effects of coenzyme Q10 supplementation on myopathy in statin-treated patients: a systematic review and meta-analysis
Meta-analysis of seven randomized controlled trials (389 participants) directly addressing statin-associated muscle pain; useful pooled evidence but limited by small trials and substantial heterogeneity.
Type 2 diabetes
Coenzyme Q10 improves blood pressure and glycaemic control: a controlled trial in subjects with type 2 diabetes
Randomized double-blind placebo-controlled factorial trial with clinically relevant blood-pressure and HbA1c outcomes; modest sample size.
The effect of coenzyme Q10 supplementation on metabolic status of type 2 diabetic patients
Randomized double-blind placebo-controlled human trial with glycemic and lipid endpoints; small sample and short duration.
SourcePMID 23831913
Effects of CoQ10 Supplementation on Lipid Profiles and Glycemic Control in Patients with Type 2 Diabetes: a randomized, double blind, placebo-controlled trial
Randomized double-blind placebo-controlled human trial; small sample with 40 completers and mixed lipid results.