CoQ10

• Heart failure support: Research suggests adjunct CoQ10 (often 300 mg/day) may improve symptoms, functional class, and left ventricular ejection fraction; one long-term RCT reported fewer major adverse cardiac events and cardiovascular deaths. Overall, evidence is moderate from RCTs and meta-analyses.
• Blood pressure: Meta-analyses indicate small, clinically modest reductions in systolic (~3–7 mmHg) and diastolic (~2–3 mmHg) blood pressure. Evidence is moderate.
• Migraine prevention: RCTs and meta-analyses show reduced attack frequency and migraine days after 4–12 weeks of use. Evidence is moderate.
• Statin-associated muscle symptoms: Some RCTs and meta-analyses show reduced myalgia severity and improved adherence; findings are mixed across trials. Evidence is moderate-to-emerging.
• Male infertility: Meta-analyses suggest improved sperm motility and concentration; impact on pregnancy/live birth is uncertain. Evidence is moderate for semen parameters.
• Glycemic control (type 2 diabetes): Meta-analyses show small improvements in fasting glucose and HbA1c; clinical significance may be limited. Evidence is emerging.
• Primary CoQ10 deficiency (rare genetic defect): High-dose CoQ10 can improve neuromuscular and systemic symptoms when deficiency is confirmed. Evidence is strong for this rare indication but not generalizable to the broader population.
• Exercise capacity/fatigue and nonalcoholic fatty liver disease: Some small trials suggest benefit; evidence is limited/emerging.
• Not supported for disease modification in Parkinson’s disease based on large negative RCTs.

Generally well tolerated. Most effects are mild and dose-related.

• Common (1–10%): Gastrointestinal upset (nausea, diarrhea, abdominal discomfort, dyspepsia), heartburn, decreased appetite, headache, dizziness, insomnia (especially if taken late in the day).
• Uncommon: Rash, pruritus, photosensitivity.
• Rare: Transient elevations in liver enzymes, hypotension (particularly in those on antihypertensives), hypersensitivity reactions.
• Lab effects: May lower INR in warfarin-treated patients (reduced anticoagulant effect).

Typical supplemental doses in studies (not prescriptive; individual needs vary):

• General/maintenance: 100–200 mg/day with food.
• Heart failure: 100–300 mg/day (often 100 mg three times daily in RCTs) for ≥3 months.
• Migraine prevention: 100–300 mg/day; benefits often seen after 4–12 weeks.
• Statin-associated muscle symptoms: 100–200 mg/day in divided doses.
• Male infertility: 200–300 mg/day for 3–6 months.
• Primary CoQ10 deficiency/mitochondrial disorders: Specialist-guided, higher doses (e.g., 150–1200 mg/day) have been used. Notes: CoQ10 is fat-soluble—take with meals to improve absorption. Ubiquinol (reduced form) may have higher bioavailability than ubiquinone. Time to effect may be several weeks (cardio/metabolic) to months (fertility).

• Known allergy/hypersensitivity to CoQ10 or formulation components.
• Warfarin therapy: Risk of reduced anticoagulant effect (lower INR) and thrombosis; avoid or use only with close medical monitoring and INR checks.
• Hypotension or on multiple antihypertensives: Additive blood pressure lowering; monitor.
• Diabetes on glucose-lowering therapy: Possible additive hypoglycemia risk; monitor glucose.
• Active cancer treatment (chemotherapy/radiation): Antioxidant effects may theoretically blunt cytotoxic therapy; discuss with oncology team before use.
• Preoperative period: Discontinue 1–2 weeks before surgery due to potential effects on blood pressure and anticoagulation management.
• Pregnancy: Limited human safety data; some studies explored preeclampsia prevention, but routine use is not established—use only under medical supervision.
• Breastfeeding: Insufficient data—avoid unless advised by a clinician.
• Pediatrics: Use in children generally limited to specialist-guided treatment of confirmed mitochondrial/primary CoQ10 deficiency.