What is Qunol (Coenzyme Q10)?
Qunol is a brand name for Coenzyme Q10 (CoQ10) supplements, where CoQ10 is a fat-soluble, vitamin-like compound that functions as an essential electron carrier in mitochondrial energy production and serves as the only endogenously synthesized lipid-soluble antioxidant in the human body. 1
Core Biochemistry and Function
CoQ10, also called ubiquinone, consists of a quinone chemical group with 10 isoprenyl subunits in its tail, explaining both its chemical name and ubiquitous presence in virtually all human cells. 1 It performs two critical functions:
Energy Production: Acts as an electron and proton carrier between mitochondrial complexes I/II and complex III, facilitating ATP synthesis—making it crucial for high-energy tissues like heart, skeletal muscle, kidneys, liver, and brain. 1, 2
Antioxidant Protection: Protects all cellular membranes, lipoproteins, and mitochondria against free radical damage generated during normal metabolism, and helps regenerate vitamin E to its active antioxidant form. 1
Additional roles include gene regulation of tissue metabolism, neuroprotection through inhibition of glutamate release and calcium influx, and possible immunomodulation. 1
Endogenous Production and Dietary Sources
The human body synthesizes approximately 500 mg/day of CoQ10 endogenously from mevalonate, tyrosine, riboflavin, folate, B12, and vitamin C, though this production declines with age. 1 Average dietary intake is only 3-6 mg/day, primarily from meat (especially beef heart with >100 mg/kg), fish (herring, trout), chicken, and nuts, while dairy products, vegetables, fruits, and cereals contain much lower levels. 1, 3
Absorption and Bioavailability Challenges
CoQ10 has inherently poor intestinal absorption due to its hydrophobicity and large molecular weight, with peak plasma levels occurring 5-10 hours after ingestion. 1, 4 The compound is transported in plasma by low-density lipoproteins (LDL), making plasma CoQ10 levels dependent on lipoprotein status. 1, 4 Taking CoQ10 with fat-containing meals significantly enhances absorption given its lipid-soluble nature. 4
A nonlinear absorption process exists where plasma concentration increases diminish as dosage increases, suggesting decreased intestinal absorption and utilization at higher doses. 1
Available Formulations
CoQ10 supplements are commercially available in two forms:
- Ubiquinone (oxidized form)
- Ubiquinol (reduced form)
No intravenous formulation exists, limiting options for patients unable to absorb oral supplements effectively. 1, 4
Clinical Dosing and Evidence
For cardiovascular benefits in patients with cardiometabolic disorders, the optimal dose appears to be 100-200 mg/day based on a U-shaped dose-response relationship, where higher doses show diminishing returns. 1 Studies have used doses ranging from 50-1200 mg/day in adults (up to 3000 mg/day), and up to 10 mg/kg/day for children. 1
The usual adult dose per FDA labeling is 1 tablet by mouth once daily or as prescribed. 5
Blood Pressure Effects
CoQ10 supplementation significantly reduces systolic blood pressure by approximately 4.77 mmHg in patients with cardiometabolic diseases, with more pronounced effects in patients with diabetes and dyslipidemia and in studies lasting >12 weeks. 1 This reduction is accompanied by a 1.62 μg/mL elevation of circulating CoQ10 compared to control groups. 1
Safety Profile
CoQ10 demonstrates remarkable safety with minimal adverse effects even at very high doses, with doses up to 3000 mg/day for 8 months being well-tolerated in neurological conditions. 2, 6, 7 The acceptable daily intake (ADI) is 12 mg/kg/day (720 mg/day for a 60 kg person), and the observed safety level (OSL) is 1200 mg/day/person. 7
Potential side effects may include:
Critical Drug Interaction
CoQ10 has a significant interaction with warfarin, potentially increasing warfarin metabolism through selective interaction with cytochrome P450 enzymes. 6 However, clinical evidence suggests that CoQ10 at 100 mg/day has no effect on warfarin's clinical action, indicating this interaction may be dose-dependent. 6 The recommended approach is to avoid CoQ10 or monitor INR more frequently if supplementation is necessary, particularly at doses above 100 mg/day. 6
Deficiency States
CoQ10 deficiency can result from genetic disorders, aging, or certain medications (particularly statins that inhibit endogenous synthesis). 1, 8 Reported symptoms include sore/aching muscles, muscle weakness, fatigue, mental confusion, gingivitis, elevated blood pressure, high cholesterol, seizures, vision/hearing loss, and kidney damage. 1
Clinical Utility Limitations
While supplementation studies have been conducted in various conditions, they have generally shown little benefit outside of primary deficiencies and specific cardiometabolic applications. 1 The quality of evidence varies: moderate for systolic blood pressure effects, low for diastolic blood pressure, and very low for circulating CoQ10 levels according to GRADE assessment. 1