Coenzyme Q10 (CoQ10) is a compound your body produces naturally. It sits in the mitochondria of your cells and plays a central role in producing adenosine triphosphate (ATP), which is the energy currency that powers virtually every cellular process. CoQ10 also functions as an antioxidant, neutralising free radicals that would otherwise damage cell membranes, proteins, and DNA.

Because CoQ10 exists in nearly all human tissues (hence its other name, ubiquinone, from “ubiquitous”), it’s particularly concentrated in organs with high energy demands: the heart, liver, kidneys, and pancreas. Unlike vitamins, which must come from your diet, your body can synthesise CoQ10 on its own. However, production tends to decline with age, and certain medications, particularly statins, can further reduce levels.

This article examines what the clinical research actually shows about CoQ10 supplementation, where the evidence is strong, and where it remains inconclusive.

What is CoQ10 and how was it discovered?

CoQ10 is a benzoquinone compound that was first isolated in 1957 by Frederick Crane at the University of Wisconsin, who extracted it from beef heart mitochondria. By 1958, researchers had identified its complete chemical structure and figured out how to synthesise it.

The compound consists of a benzoquinone ring attached to a long chain of isoprene units. In humans, this chain contains 10 isoprene groups, hence the “Q10” designation. Different species have different chain lengths (yeast primarily uses CoQ6, for instance).

CoQ10 exists in two forms in the body: ubiquinone (the oxidised form) and ubiquinol (the reduced form). About 90% of the CoQ10 circulating in your blood is in the ubiquinol form. Both forms can be converted back and forth as part of the electron transport chain in mitochondria.

Why CoQ10 matters physiologically

The primary function of CoQ10 is shuttling electrons in the mitochondrial electron transport chain. This process is how your cells generate ATP. Without adequate CoQ10, this energy production becomes less efficient.

Beyond energy production, CoQ10 in its reduced form (ubiquinol) works as a lipid-soluble antioxidant. It can regenerate other antioxidants like vitamin E and protect cell membranes from oxidative damage. Research also shows that CoQ10 can inhibit inflammatory signalling pathways, particularly NF-κB, which regulates the expression of genes involved in inflammation and immune responses [1].

Food sources of CoQ10

You can obtain CoQ10 from food, though dietary intake typically provides only a small fraction of what your body produces internally.

Animal sources tend to be richest: organ meats (particularly heart and liver), beef, pork, chicken, and fatty fish like mackerel, sardines, and trout. A 100g serving of beef heart contains roughly 11mg of CoQ10, while the same amount of chicken has around 1.4mg.

Plant sources include: spinach, broccoli, cauliflower, oranges, strawberries, lentils, peanuts, and soybeans, though concentrations are generally lower than in animal products.

One study found that absorption rates from food versus supplements are actually quite similar, so if you’re eating a varied diet that includes these foods, you’re likely getting a reasonable baseline amount [2].

Proven and possible benefits of CoQ10

1. Blood lipid regulation

A meta-analysis of 21 randomised controlled trials involving over 1,000 participants with metabolic conditions found that CoQ10 supplementation (doses between 100-300mg daily) significantly reduced triglyceride levels. However, it didn’t show meaningful effects on total cholesterol, LDL cholesterol, or HDL cholesterol [3].

My take: if you’re specifically trying to address triglycerides and already have metabolic issues, CoQ10 might be worth considering alongside standard treatments. For general cholesterol management, the evidence isn’t compelling.

2. Physical fatigue during exercise

An 8-day double-blind study in 17 healthy subjects found that 300mg daily of CoQ10 improved recovery speed after fatiguing physical tasks and reduced subjective feelings of fatigue compared to placebo [4].

This is a small study, so I wouldn’t overstate the effect. But for people who exercise regularly and are looking for marginal gains in recovery, there’s at least some rationale here.

3. Vascular endothelial function

The endothelium is the inner lining of blood vessels, and its health is considered an early marker for cardiovascular risk. A meta-analysis of 5 randomised controlled trials (194 participants) found that CoQ10 supplementation improved endothelial function as measured by flow-mediated dilation [5].

That’s good news for cardiovascular risk, though nobody has followed participants long enough to see if it actually prevents heart attacks or strokes.

4. Weight management

A systematic review of 17 randomised controlled trials found no significant effect of CoQ10 supplementation on body weight or body mass index [6]. The dose and duration of supplementation didn’t change this conclusion.

I should be direct here: CoQ10 is not a weight loss supplement. If you see it marketed that way, be sceptical.

Results here are mixed. A 24-week study in 236 breast cancer patients undergoing chemotherapy found no improvement in fatigue or quality of life from CoQ10 supplementation [7]. However, a 12-week study in 48 patients with multiple sclerosis found that 500mg daily did improve fatigue and depression scores [8].

The difference might relate to the underlying mechanisms of fatigue in different conditions. In MS, mitochondrial dysfunction may play a larger role, making CoQ10 more relevant.

6. Blood sugar control in type 2 diabetes

A meta-analysis of 13 randomised controlled trials involving 765 people with type 2 diabetes found that CoQ10 supplementation lowered fasting blood glucose, glycosylated haemoglobin (HbA1c), and triglycerides while increasing HDL cholesterol [9].

This is reasonably good evidence, though the effect sizes are modest. CoQ10 isn’t a replacement for proper diabetes management, but it might be a useful adjunct for people already working on blood sugar control through diet, exercise, and medication.

For more on diabetes-related concerns, see our guide on diabetic bladder dysfunction.

7. Migraine prevention

A meta-analysis of 5 studies involving 346 migraine patients found that CoQ10 reduced the number of migraine days per month and the duration of attacks compared to placebo [10]. It didn’t significantly affect attack frequency or severity, but fewer migraine days is still meaningful for sufferers.

Why would CoQ10 help migraines? The brain uses enormous amounts of energy, and mitochondrial dysfunction has been linked to migraines in some research. CoQ10’s anti-inflammatory effects might also play a role.

Population studies have found that low CoQ10 levels correlate with poor muscle strength and muscle mass in older adults [11]. Muscles need ATP to contract, so a link between mitochondrial function and muscle health isn’t surprising.

However, I should note that observational correlation isn’t the same as proving supplementation helps. Trials specifically testing whether CoQ10 prevents or reverses sarcopenia are still lacking.

9. Inflammatory markers

A systematic review of 17 randomised double-blind controlled trials found that CoQ10 supplementation significantly reduced C-reactive protein (CRP), interleukin-6 (IL-6), and tumour necrosis factor alpha (TNF-α), all of which are markers of systemic inflammation [12].

Chronic low-grade inflammation shows up in cardiovascular disease, diabetes, and various age-related conditions. Lowering these markers might matter for long-term health, though we’d need outcome studies to know for sure. CoQ10 appears to do this by blocking NF-κB, the master switch for inflammatory gene expression.

10. Heart failure

Heart failure is where CoQ10 research gets genuinely interesting. A meta-analysis of 14 randomised controlled trials involving over 2,100 patients with heart failure found that CoQ10 supplementation reduced mortality by 31% and improved exercise capacity [13]. The effect on left ventricular ejection fraction and NYHA classification wasn’t statistically significant, but the mortality reduction is substantial.

The Q-SYMBIO trial, which followed heart failure patients for 2 years, found that those taking 300mg of CoQ10 daily had significantly fewer major adverse cardiac events [14].

If you have heart failure, this is something to discuss with your cardiologist.

11. Male fertility

A meta-analysis of 3 studies (296 participants) found that CoQ10 increased sperm concentration and motility [15]. However, the studies didn’t report whether this translated into higher pregnancy rates or live births.

This is a common limitation in fertility research: surrogate markers improve, but the outcome that matters (having a baby) isn’t measured. Still, for men with fertility issues, CoQ10 is relatively safe and might be worth trying as part of a broader approach.

For more on this topic, see the related article on arginine and male reproductive health.

12. Blood pressure

A Cochrane review of 2 randomised controlled trials found that CoQ10 produced small reductions in blood pressure (systolic dropped by about 3.7 mmHg, diastolic by about 2 mmHg), but these reductions were not considered clinically significant [16].

For context, the threshold for clinical significance is typically around 5 mmHg systolic. CoQ10 isn’t going to replace blood pressure medication.

13. Polycystic ovary syndrome (PCOS)

A 12-week double-blind study in 60 women with PCOS found that 100mg of CoQ10 daily improved fasting blood glucose, insulin levels, total cholesterol, and LDL cholesterol [17].

PCOS is a complex condition with metabolic components, and CoQ10’s effects on glucose metabolism and inflammation may be relevant here. This is a single study though, so more research would help confirm the finding.

14. Parkinson’s disease

Here’s where expectations have fallen short of the theory. Parkinson’s patients have been found to have CoQ10 levels 4-5 times lower than healthy individuals [18], which initially suggested supplementation might help.

However, a systematic review of 5 randomised controlled trials involving 981 Parkinson’s patients found that CoQ10 supplementation provided no benefit and didn’t slow disease progression [19].

This is disappointing but illustrates an important point: low levels of something in disease don’t automatically mean supplementing will help.

Side effects and safety

CoQ10 is well-tolerated. Clinical trials have tested doses up to 3,000mg daily for 8 months, 1,200mg daily for 16 months, and 600mg daily for 30 months without serious adverse effects [20][21][22]. That’s reassuring, though it doesn’t mean mega-doses are necessary or useful.

Mild side effects that have been reported include:

Stomach upset, nausea, or heartburn
Loss of appetite
Diarrhoea (particularly at doses above 200mg daily)
Insomnia
Mild dizziness
Skin rash in sensitive individuals
Light sensitivity
Irritability

These side effects are uncommon and generally resolve when the dose is reduced.

Safety precautions and contraindications

1. Pregnancy and breastfeeding

Studies suggest CoQ10 is safe when started after about 20 weeks of pregnancy. However, safety during breastfeeding hasn’t been established, so most guidance recommends avoiding it while nursing.

2. Chemotherapy drug interactions

CoQ10 may reduce the effectiveness of certain chemotherapy drugs, particularly alkylating agents like busulfan, carboplatin, cisplatin, cyclophosphamide, dacarbazine, and thiotepa. If you’re undergoing cancer treatment, consult your oncologist before taking CoQ10.

3. Blood pressure medications

Because CoQ10 can modestly lower blood pressure, use caution if you’re already taking antihypertensives. This includes ACE inhibitors (captopril, enalapril), angiotensin receptor blockers (losartan, valsartan), calcium channel blockers (diltiazem, amlodipine), and diuretics (hydrochlorothiazide, furosemide).

For information on lower urinary tract symptoms that may occur with some blood pressure medications, see our related guide.

4. Surgery

Discontinue CoQ10 at least two weeks before scheduled surgery, as it may affect blood pressure control during and after the procedure.

5. Warfarin and anticoagulants

CoQ10 has a similar chemical structure to vitamin K and may promote blood clotting, potentially reducing warfarin’s effectiveness. If you take warfarin and want to use CoQ10, you’ll need more frequent monitoring of your INR (clotting time), especially during the first few weeks.

This interaction also applies to other supplements that affect clotting. For more information, see our article on aspirin and similar compounds.

6. Timing considerations

Taking CoQ10 in the evening may cause insomnia in some people, likely because of its role in cellular energy production. Most practitioners recommend morning or afternoon dosing.

Dosage recommendations

Standard supplemental doses range from 90mg to 200mg daily. For specific conditions, research has used higher doses:

Heart failure: 100-300mg daily
Migraine prevention: 100-300mg daily
Diabetes support: 100-200mg daily
Fertility support: 200-300mg daily
Statin users: 100-200mg daily

Because CoQ10 is fat-soluble, absorption is significantly better when taken with food, especially meals containing fat. One study found that taking CoQ10 with a fatty meal increased intestinal absorption by about threefold [23].

Ubiquinol versus ubiquinone

Supplements come in two forms: ubiquinone (oxidised) and ubiquinol (reduced). Both can raise blood levels of CoQ10.

A comparative study found that after 4 weeks of supplementation, ubiquinol increased plasma CoQ10 by 4.77 times, while ubiquinone increased it by 2.77 times [24]. This suggests ubiquinol has roughly 1.7 times better bioavailability.

However, ubiquinol supplements are also more expensive. For most people, standard ubiquinone is probably adequate, especially if taken with food. Ubiquinol might be worth the extra cost for older adults (who may have more difficulty converting ubiquinone) or those with significant health conditions.

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