For Patients & Caregivers
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. During periods of ischemia (lack of oxygen), such as occurs during a heart attack, CoQ10 has been 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 is able to neutralize 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.
- As an antioxidant
Laboratory studies show that CoQ10 has antioxidant effects.
- To treat breast cancer
A few case reports describe remission of breast cancer when treated with high doses of CoQ10, but this is insufficient evidence to support this use.
- To manage cardiovascular disease
Several studies show CoQ10 improves left ventricular function and reduce hypertension. Other studies yielded negative results.
- To reduce high cholesterol
Clinical trials show inconsistent results: two indicate an increase in HDL, one shows a decrease in LDL, while two others indicate that coenzyme Q10 has no effect on LDL oxidation (which contributes to the development of atheroclerotic plaques in the blood vessels).
- To prevent cardiac toxicity from anthracyclines
One clinical trial supports this use, but additional studies are needed.
- To improve athletic performance
Clinical trials do not support this use.
- To prevent the progression of Parkinson’s disease
One clinical trial showed that high doses of coenzyme Q10 slowed the progression of Parkinson’s disease, but larger clinical trials are needed to support this use.
- To treat Huntington’s disease
Data from a single clinical trial do not support this use.
- To treat periodontal disease (disease of the gum, teeth, and underlying bone)
One study supports this use, but additional clinical trials are needed.
- To treat infertility
Coenzyme Q10 improved sperm motility, but it is not known if it can be used to treat infertility
- You are taking Warfarin (CoQ10 may alter its effects.
- You are undergoing chemotherapy (Theoretically, because it is an antioxidant, CoQ10 may decrease the effectiveness of chemotherapy; patients should consult with their oncologist).
- You are taking Theophylline (CoQ delays the clearance of theophylline, 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, at higher concentrations 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 indicate antioxidant and neuroprotective effects (17) (18), and the ability to alleviate radiation-induced nephropathy (34).
Data from some studies suggest beneficial effects of CoQ10 in patients with coronary artery disease (2), congestive heart failure (21), and for reducing risk of cardiovascular mortality (42). But a systematic review concluded that current evidence does not support CoQ10 supplementation in patients with coronary heart disease (43). Supplementation may increase sperm motility in asthenozoospermic men (8); modulate expression of insulin, lipid and inflammatory markers in women with polycystic ovary syndrome (POCS) (35); and reduce fatigue induced by physical exertion (9). In addition, neuroprotective effects were reported in patients with progressive supranuclear palsy (5) as well as those with early Parkinson’s disease (6) (33), but not in patients with mid-stage Parkinson’s disease (7). Case reports also suggest that CoQ10 supplementation improves postural hypotension, a hallmark of multiple-system atrophy (36) and adjuvant CoQ10 was shown to improve symptoms of depression in patients with bipolar disorder (44). But a mixture of antioxidants, including CoQ10, vitamins C, E, and lipoic acid was found ineffective against Alzheimer’s disease (20).
CoQ10 may also play a role in preventing migraines (22). A small study showed a reduction in the frequency of migraine headaches following supplementation (23), but a randomized trial failed to find benefit (24). More research is warranted. Further, the observation that patients on statin therapy have decreased concentrations of CoQ10 in muscle cells (25) resulted in efforts to evaluate the benefit of CoQ10 in alleviating statin-induced myalgias. Data are inconclusive (26) (27) (28) (45).
CoQ10 has also been investigated for anticancer effects. In a study of patients with hepatocellular carcinoma, coenzyme Q10 levels were positively associated with antioxidant capacity and negatively correlated with inflammation markers, post surgery (37), suggesting a role for CoQ10 as an antioxidant therapy. In studies of breast cancer patients, a combination of CoQ10 and L-carnitine was found effective in controlling moderate-severe cancer-related fatigue (CRF) (38). And according to case reports, supplementation may be useful for treating the cancer (3) (4), although a randomized trial reported no benefit in improving self-reported fatigue or quality of life (29). Further research is needed (39).
CoQ10 may interfere with the actions of warfarin (11) (12). Because of its antioxidant property, CoQ10 may also reduce effectiveness of chemotherapy and radiation therapy (13).
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 episodes of ischemia, and it may help maintain the integrity of myocardial calcium ion channels during ischemic insults (2). CoQ10 may also be capable of stabilizing cellular membranes and preventing depletion of metabolites required for ATP resynthesis (10), and suppressing 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).
In addition, CoQ10 was shown to prevent the reduction of glucose transporter-4 (GLUT4) protein levels in adipocytes caused by simvastatin, which is a likely mechanism against statin-induced diabetes (31). It also reduced high glucose-induced apoptosis and dysfunction of endothelial progenitor cells by up-regulating endothelial nitric oxide synthase (eNOS) and heme oxygenase (HO-1) through the AMP-activated protein kinase pathway (41). In a murine model, it was shown to afford protection against doxorubicin-induced testicular toxicity by ameliorating oxidative stress, reducing apoptosis and by up-regulating 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, there are reports that CoQ10 can increase the risk of bleeding when used with warfarin (12).
Theophylline: CoQ10 delays the clearance of theophylline, which can cause persistent vomiting, cardiac arrhythmias, and intractable seizures (19).