For Patients & Caregivers
How It Works
Coenzyme Q10 has not been shown to treat or prevent cancer.
Coenzyme Q10 (CoQ10) is produced naturally by all cells in the body. It is necessary for production of adenosine triphosphate (ATP), the “fuel” of all living cells. In episodes where a lack of oxygen occurs such as during a heart attack, CoQ10 was shown to reduce damage to heart tissue and its mitochondria, where ATP production takes place. It is known to be an antioxidant and to stabilize cell and organelle membranes. In animal studies, coenzyme Q10 neutralized free radicals, which can damage DNA and cells. However, absorption of oral coenzyme Q10 through the intestine is low.
Due to its antioxidant activity, CoQ10 may interfere with the actions of certain chemotherapy drugs and radiation therapy.
- To prevent and treat cancer A few older case reports describe remission of breast cancer when treated with high doses of CoQ10, but this is insufficient evidence to support use.
- To manage cardiovascular disease Several studies show CoQ10 improves left ventricular function and reduces hypertension. Other studies yielded negative results.
- To reduce high cholesterol Clinical trials show inconsistent results: some indicate an increase in HDL, one showed a decrease in LDL. Other studies suggest no effect on LDL oxidation, which contributes to the development of plaque in blood vessels.
- To reduce fatigue Studies on whether CoQ10 supplementation can help reduce fatigue are mixed.
- To prevent the progression of Parkinson’s disease One clinical trial showed that high doses of CoQ10 slowed the progression of Parkinson’s disease, but larger clinical trials are needed to support this use.
- To treat Huntington’s disease A large multicenter trial did not find benefit with CoQ10 supplementation.
- To treat infertility Coenzyme Q10 improved sperm motility, but it is not known if it can be used to treat infertility.
Do Not Take If
- You are taking warfarin: CoQ10 may alter its effects and increase bleeding risk.
- You are undergoing chemotherapy or radiation therapy: Theoretically because it is an antioxidant, CoQ10 may decrease effectiveness of these cancer treatments. Patients should consult with their oncologist.
- You are taking theophylline: CoQ delays theophylline clearance, which may cause persistent vomiting, cardiac arrhythmias, and intractable seizures.
For Healthcare Professionals
Coenzyme Q10 (CoQ10), also known as ubiquinone, is involved in cellular respiration and energy production. It is found in all human cells, with higher concentrations found in the liver, kidney, heart, and pancreas. It is also consumed as a dietary supplement for its antioxidant effects and is often promoted as a preventive agent for cardiovascular diseases, Parkinson’s disease, infertility, and cancer. Studies using murine models suggest antioxidant and neuroprotective effects (17) (18), and the potential to alleviate radiation-induced nephropathy (34).
Data from some human studies suggest CoQ10 may benefit patients with coronary artery disease (2) and congestive heart failure (21), and reduce risk of cardiovascular mortality (46). In a long-term trial, dietary supplementation with a combination of selenium and CoQ10 also improved cardiac function and significantly reduced mortality (43) (47). However, a systematic review concluded that current evidence does not support routine CoQ10 supplementation in patients with coronary heart disease (42).
Observations that patients on statins have decreased CoQ10 concentrations in muscle cells (25) resulted in efforts to evaluate CoQ10 for statin-induced myalgias, but data are inconclusive (26) (27) (28) (45) (52). Short-term CoQ10 supplementation in diabetic hemodialysis patients improved markers of insulin metabolism, but not fasting glucose, HbA1c, or lipid profiles (48). A meta-analysis concluded that evidence of benefit for diabetic kidney disease is limited and that additional study is needed (49).
CoQ10 may be helpful in some cases for migraine prevention (22). A small study found reduced migraine frequency following supplementation (23), and other data suggest it may reduce number of migraine days and duration, but not number of attacks or severity (50). A randomized trial of add-on supplementation in pediatric migraine failed to find benefit (24).
In other studies, adjuvant CoQ10 improved depressive symptoms in patients with bipolar disorder (44), but an antioxidant mixture including CoQ10, vitamins C and E, and lipoic acid was ineffective against Alzheimer’s disease (20). Neuroprotective effects were reported in patients with progressive supranuclear palsy (5) and those with early (6) (33) but not mid-stage (7) Parkinson’s disease. Case reports also suggest CoQ10 supplementation improves postural hypotension, a hallmark of multiple-system atrophy (36). However, a large multicenter trial found CoQ supplementation ineffective in slowing functional decline of Huntington’s disease (51).
Other data suggest CoQ10 supplementation may increase sperm motility in men (8), modulate expression of insulin, lipid, and inflammatory markers in women with polycystic ovary syndrome (35), and reduce fatigue from physical exertion (9); affect reductions in oxidative stress markers (53); as well as inflammatory markers in patients with chronic diseases (54). In a study involving patients with sepsis, supplementation in early phase had a positive effect on clinical parameters and mitochondrial dysfunction (55).
CoQ10 has also been investigated for anticancer effects. In patients with hepatocellular carcinoma, coenzyme Q10 levels were positively associated with antioxidant capacity and negatively correlated with inflammation markers post-surgery (37). In breast cancer patients, a combination of CoQ10 and L-carnitine helped control cancer-related fatigue (38); and in patients on tamoxifen therapy, CoQ10 was found effective in lowering inflammatory cytokine levels (56). Older case reports suggest supplementation may be useful for treating the cancer (3) (4), although a randomized trial found no benefit against self-reported fatigue or quality of life (29). Furthermore, antioxidant supplementation, including CoQ10, before and during treatment, was associated with an increased hazard of recurrence in breast cancer patients (57). More research is needed (39).
CoQ10 may interfere with the actions of warfarin (11) (12). Because of its antioxidant properties, it may also reduce effectiveness of chemotherapy and radiation therapy (13).
Mechanism of Action
CoQ10 is known to have antioxidant and membrane-stabilizing properties and is the only endogenously produced lipid with a redox function in mammals. All cells are capable of synthesizing CoQ10 and no redistribution between organs occurs through the blood. It is necessary for adenosine triphosphate (ATP) production, and its role as a mobile electron carrier in the mitochondrial electron-transfer processes of respiration and coupled phosphorylation is well established. It also has a direct regulatory role on succinyl and NADH dehydrogenases (1). CoQ10 has been shown to scavenge free radicals produced by lipid peroxidation and prevent mitochondrial deformity during ischemic episodes, and may help maintain integrity of myocardial calcium ion channels during ischemic insults (2). CoQ10 may also stabilize cellular membranes and prevent depletion of metabolites required for ATP resynthesis (10), and suppress age-related inflammatory reactions and osteoclast differentiation by inhibiting oxidative stress (30). One of the mechanisms underlying the neuroprotective effects of CoQ10 involves inhibition of microglia in pentylenetetrazol-induced kindling epilepsy in mice (40).
Other preclinical studies suggest CoQ10 can prevent reduced glucose transporter-4 protein levels in adipocytes caused by simvastatin, which may contribute to the risk of new-onset diabetes in patients on statins (31). It also reduced high glucose-induced apoptosis and dysfunction of endothelial progenitor cells by upregulating endothelial nitric oxide synthase and heme oxygenase via the AMP-activated protein kinase pathway (41). In a murine model, it protected against doxorubicin-induced testicular toxicity by ameliorating oxidative stress, reducing apoptosis, and by upregulating testicular P-glycoprotein (32).
HMG-CoA reductase inhibitors: Endogenous levels of CoQ10 may be reduced by lovastatin, atorvastatin and simvastatin. The HMG-CoA reductase enzyme is responsible for catalyzing the conversion of acetyl CoA to cholesterol and synthesis of CoQ10 (14).
Warfarin: CoQ10 is structurally similar to vitamin K and may antagonize the effects of warfarin (11). However, CoQ10 has been reported to increase the risk of bleeding when used with warfarin (12).
Theophylline: CoQ10 delays theophylline clearance, which can cause persistent vomiting, cardiac arrhythmias, and intractable seizures (19).