Coenzyme Q10

Natural Medicines rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for Coenzyme Q10 are as follows:

Likely Effective for...

• Coenzyme Q10 deficiency. Taking coenzyme Q10 by mouth seems to improve symptoms of coenzyme Q10 deficiency. This is a very rare condition. The symptoms include weakness, fatigue, and seizures.
• Disorders that limit energy production in the cells of the body (mitochondrial disorders). Taking coenzyme Q10 by mouth seems to reduce symptoms of mitochondrial disorders. However, improvement in symptoms is slow. Some people have to take coenzyme Q10 for 6 months to get the most benefit.

Possibly Effective for...

• Age-related vision loss (age-related macular degeneration). Taking a specific product containing coenzyme Q-10, acetyl-L-carnitine, and omega-3 fatty acids (Phototrop) by mouth seems to improve vision in people with age-related vision loss.
• Preventing death due to heart problems. Some research suggests that taking coenzyme Q10 along with selenium might reduce the chance of heart-related death in the elderly.
• Heart failure. Early research found that heart failure might be linked with low coenzyme Q10 levels. Some research shows that taking coenzyme Q10 might help reduce some symptoms of heart failure. Coenzyme Q10 might also reduce the chances of having an abnormal heart rhythm related to heart failure. Some research suggests it works best in people who are not taking conventional medications for heart failure, such as an ACE inhibitor.
• Nerve damage caused by diabetes (diabetic neuropathy). Research shows that taking coenzyme Q-10 improves nerve damage and nerve pain in people with nerve damage caused by diabetes.
• Fibromyalgia. Some research show that taking coenzyme Q10 by mouth seems to reduce pain by over 50%, fatigue by 47%, morning tiredness by 56%, and tender points by 44% in people with fibromyalgia.
• HIV/AIDS. Taking coenzyme Q10 by mouth seems to improve immune function in people with HIV/AIDS.
• An inherited neurological disorder called Huntington's disease. Ubiquinol, an altered form of coenzyme Q10, has been granted "Orphan Drug Status" by the U.S. Food and Drug Administration (FDA). This gives the maker of Ubiquinol some financial incentives to study its effectiveness for Huntington's, a condition that is so rare (affecting less than 200,000 individuals) that pharmaceutical companies might not otherwise invest in developing a drug for it. However, taking coenzyme Q10 by mouth in doses of 600 mg daily or less does not seem to be effective for slowing the progression of Huntington's disease.
• Blood vessel complications caused by heart bypass surgery. Reduced blood supply during heart or blood vessel surgery can deprive tissue of oxygen. When blood supply returns to this tissue, the tissue can become damaged. There is some evidence that taking coenzyme Q10 by mouth for at least one week before heart bypass surgery or blood vessel surgery might help to reduce tissue damage. However, not all research agrees with this finding.
• A specific type of high blood pressure. Taking coenzyme Q10 by mouth daily appears to lower systolic blood pressure (the top number) in some people with high systolic blood pressure but normal diastolic blood pressure (the bottom number).
• Migraine headache. Taking coenzyme Q10 by mouth seems to help prevent migraine headaches. Studies show it can decrease the frequency of headaches by about 30% and the number of days with headache-related nausea by about 45% in adults. More than half of patients taking coenzyme Q10 experience a 50% decrease in the number of headache days per month. Taking coenzyme Q10 also appears to reduce migraine frequency in children who have low levels of coenzyme Q10. It can take up to 3 months for significant benefit. However, coenzyme Q10 does not seem to be effective in treating migraines once they have developed.
• A muscle disorder called muscular dystrophy. Taking coenzyme Q10 by mouth seems to improve physical performance in some people with muscular dystrophy.
• Heart attack. When started within 72 hours of a heart attack and taken for one year, coenzyme Q10 appears to lower the risk of heart-related events, including another heart attack.
• Painful erection in men (Peyronie's disease). Research shows that taking coenzyme Q10 improves erectile function in men with painful erections.

Possibly Ineffective for...

• Alzheimer's disease. Taking coenzyme Q10 does not seem to improve mental function in people with Alzheimer's disease.
• Neurodegenerative disease called ALS or Lou Gehrig's disease. Research shows that taking coenzyme Q10 does not slow the progression of ALS.
• Fatigue due to cancer drugs. Taking coenzyme Q10 does not seem to reduce - fatigue in people being treated for breast cancer.
• Cocaine dependence. Taking a combination of coenzyme Q10 and L-carnitine does not reduce cocaine use.
• High cholesterol. Taking coenzyme Q10 does not seem to reduce total cholesterol, triglycerides, or low-density lipoprotein (LDL or "bad") cholesterol, or increase high-density lipoprotein (HDL or "good") cholesterol.
• Symptoms affecting polio survivors (post-polio syndrome). Research shows that taking coenzyme Q10 does not improve muscle strength or muscle function in people with post-polio syndrome.

Likely Ineffective for...

• Athletic performance. Taking coenzyme Q10 by mouth, alone or with other ingredients, does not improve athletic performance in athletes or non-athletes.

Insufficient Evidence to Rate Effectiveness for...

• Chest pain (angina). Some early research suggests that taking coenzyme Q10 by mouth might reduce chest pain and improve exercise ability in people with angina.
• Heart toxicity caused by cancer drugs. Early research suggests that taking coenzyme Q10 by mouth might protect the heart in children aged 3-12 years who are being treated with a class of drugs called anthracyclines. However, results from larger studies are inconsistent.
• Asthma. Some early research suggests that taking a combination of coenzyme Q10, vitamin E (alpha-tocopherol), and vitamin C in addition to conventional asthma treatment reduces the dosage of drugs needed by people with mild-to-moderate asthma. However, it does not appear to improve lung function or reduce blockage of airways.
• Autism. Early research shows that taking an specific form of coenzyme Q10 called ubiquinol improves autism symptoms in autism patients aged 3-6 years according to parent assessment. Higher quality studies are needed to confirm these results.
• Mental health disorder of extreme mood swings (bipolar disorder). Early research shows that taking coenzyme Q10 improve symptoms of depression in people over 55 years of age with bipolar disorder.
• Breast cancer. Some research in Chinese women suggests that having low blood levels of coenzyme Q10 is linked to an increased risk of breast cancer. Also, early research shows that taking coenzyme Q10 by mouth might be helpful in advanced breast cancer when used along with surgery and conventional treatment plus other antioxidants and omega-3 and omega-6 fatty acids. Higher quality studies are needed to confirm these results.
• Cancer. Low coenzyme Q10 levels seem to be linked with an increased risk of skin cancer. Early research suggests that taking coenzyme Q10 along with other antioxidants increases survival time by 40% in patients with terminal cancer. Higher quality studies are needed to confirm these results.
• Brain damage that affects muscle movement (cerebellar ataxia). Early research suggests that taking coenzyme Q10 by mouth can improve posture and muscle function in people with cerebellar ataxia and low coenzyme Q10 levels. However, it doesn't seem to benefit people with normal coenzyme Q10 levels.
• Lung disease called chronic obstructive pulmonary disease (COPD). Early research suggests that taking coenzyme Q10 does not improve lung function or exercise performance in people with COPD.
• Cyclic vomiting syndrome. Early research suggests that taking coenzyme Q10 might work as well as prescription medications used to treat cyclic vomiting syndrome.
• Diabetes. Research about the effectiveness of coenzyme Q10 for diabetes is conflicting. Some research shows that taking coenzyme Q10 might lower blood sugar levels in people with type 2 diabetes. However, other research has found no benefit in people with type 1 or type 2 diabetes.
• Weakened and enlarged heart (dilated cardiomyopathy). Early research suggests that taking coenzyme Q10 improves heart function in children with dilated cardiomyopathy.
• Dry mouth. Early research suggests that taking an altered form of coenzyme Q10 called ubiquinol improves dry mouth.
• Eye surgery. Research suggests that administering an eye solution containing coenzyme Q10 and vitamin E increases the speed of nerve regeneration after cataract eye surgery.
• Rare inherited disease that causes nerve damage (Friedreich's ataxia). Some early research shows that taking coenzyme Q10 plus vitamin E improves heart function but not posture or manner of walking in in people with Friedreich's ataxia. However, other early research suggests that taking vitamin E together with coenzyme Q10 helps prevent decline in coordination, posture, and movement in people with Friedreich's ataxia compared to no treatment. Coenzyme Q10 seems to work best in patients with low coenzyme Q10 levels at baseline.
• Hearing loss. Some research suggests that taking a specific coenzyme Q10 product (Q-TER) by mouth improves hearing in people with age-related hearing loss. However, combining coenzyme Q10 with conventional steroid treatments does not improve hearing more than steroid treatment alone in people with sudden deafness. Also, it doesn't appear to improve hearing in people with noise-induced hearing loss.
• Hepatitis C. Research shows that taking coenzyme Q-10 does not improve liver function in people with hepatitis C who are not responding to conventional treatment.
• High blood pressure. Some early research shows that taking coenzyme Q10 by itself or along with other medications for treating high blood pressure helps lowers blood pressure in people with high blood pressure. However, not all research has shown benefit. Coenzyme Q10 might only benefit people with high blood pressure who also have low blood levels of coenzyme Q10 before treatment.
• A condition of an enlarged heart called hypertrophic cardiomyopathy. Taking coenzyme Q-10 by mouth seems to decrease the thickness of the heart wall and decrease symptoms of shortness of breath and fatigue in people with hypertrophic cardiomyopathy.
• Male infertility. There is some early evidence that taking coenzyme Q10 or an altered form of coenzyme Q10 called ubiquinol by mouth can improve the movement and density of sperm in men with certain types of infertility. It appears that these benefits require at least 6 months of treatment. However, these improvements may not increase pregnancy rate.
• Inherited diabetes and deafness. Early research suggests that taking coenzyme Q10 by mouth might prevent the progression of a rare form of diabetes that is maternally inherited.
• Parkinson's disease. Some research shows that taking coenzyme Q10 might slow mental decline in people with early-stage Parkinson's disease. At least 16 months of treatment and doses above 600 mg daily appear to be needed to achieve these benefits. However, not all evidence has been positive. Other research suggests that coenzyme Q10 does not benefit people with early or mid-stage Parkinson's disease.
• Gum disease. Applying coenzyme Q10 to the gums is not effective for treating gum disease. However, there is some early evidence that taking coenzyme Q10 by mouth might be helpful in treating gum disease.
• Rare genetic disorder called Prader-Willi syndrome. Early research suggests that administering coenzyme Q10 improves mental and physical development in children with Prader-Labhart-Willi syndrome. However, it is not clear if these improvements are due to the coenzyme Q10 or an age-related phenomenon.
• High blood pressure during pregnancy (pre-eclampsia). Pre-eclampsia is a condition that some women develop during pregnancy. Some research shows that women who are at risk have a lower chance of developing the condition if they take coenzyme Q10 from week 20 of pregnancy until the baby is delivered.
• Prostate cancer. Research shows that taking a combination of vitamin E, selenium, vitamin C, and coenzyme Q10 does not improve biomarkers for prostate cancer.
• Kidney failure. Some early research suggests that taking coenzyme Q10 improves kidney function in people with end-stage kidney disease. However, other research shows that taking coenzyme Q10 does not improve kidney function.
• A muscle condition called "statin-induced myopathy." Statins, a class of drugs used to lower cholesterol, can sometimes cause muscle pain. There is some evidence that taking coenzyme Q10 might reduce this pain. However, not all evidence has been positive.
• Hair loss related to use of the warfarin. There is some early evidence that taking coenzyme Q10 might be helpful for preventing hair loss caused by the blood-thinning drug, warfarin.
• Wrinkled skin. Early evidence suggests that applying a coenzyme Q10 cream to the skin improves wrinkled skin.
• Fatigue.
• Lyme disease.
• Other conditions.

More evidence is needed to rate coenzyme Q10 for these uses.