Quick answer

CoQ10 is a compound your body makes and uses inside cells to produce energy. Human studies usually use 90 to 390 mg a day. Supplements reliably raise the amount in the blood, but effects on energy and exercise in healthy adults are small and inconsistent. It can make warfarin less effective.^1,2,3

Key facts

Your body makes CoQ10, and the highest levels are in the heart, liver, kidneys and pancreas.^1,4
Tissue levels of CoQ10 fall as people age.¹
Food supplies only about 3 to 6 mg a day, mostly from meat, fish, nuts and some oils.⁵
Statins lower the amount of CoQ10 in the blood.^1,6
No serious side effects have been reported, though mild trouble sleeping and stomach upset can occur.^1,4

What CoQ10 is

Coenzyme Q10 takes its name from its chemistry: a quinone group and 10 repeating subunits. A coenzyme is a small molecule, not a protein, that an enzyme needs in order to work.¹

CoQ10 is found in most tissues, with the highest levels in the heart, liver, kidneys and pancreas and the lowest in the lungs.^1,4

Inside mitochondria, the parts of a cell that turn food into usable energy, CoQ10 passes electrons along the chain of reactions that makes ATP, the cell's energy currency. The body also uses it as an antioxidant.¹

Tissue levels of CoQ10 fall as people age, because the body needs more, makes less, or lacks enough of the building blocks it makes CoQ10 from.¹

Statins lower the amount of CoQ10 in the blood. Across 12 randomized trials with 1,776 people, levels fell whatever the type or intensity of the statin.^1,6

What the evidence shows

One claim reaches a moderate grade, and it is about blood levels. The cell energy claim is graded early: the biochemistry is established, but evidence that extra CoQ10 makes a difference to healthy adults is weak. Under each is the amount the studies used.

Raises blood levels of CoQ10*^1,2,7

Moderate evidence

A 2025 meta-analysis of 24 placebo-controlled studies in healthy adults found that CoQ10 supplements consistently raised blood CoQ10. How much depends on the product. A National Institutes of Health summary notes that oil-based preparations are absorbed better than the plain compound. In one small crossover trial, 200 mg a day of ubiquinone for two weeks did not raise levels significantly in ten older men, while the same dose of ubiquinol did.

Amount studied: Usually 90 to 390 mg a day in human studies; 200 mg a day for two weeks in the crossover trial

Supplies CoQ10, which cells use to produce energy and as an antioxidant*^1,2,7,8,9

Early evidence

The role of CoQ10 in the cell's energy-producing machinery is established biochemistry. Evidence that taking more helps healthy adults is weak. A 2025 meta-analysis of 24 studies in healthy adults found small, inconsistent effects on exercise performance and only suggestive evidence of less fatigue, with certainty rated very low to low. In a 2022 meta-analysis of fatigue, 10 of the 13 trials were in people with medical conditions. In ten older men, two weeks at 200 mg a day changed neither blood markers of oxidative stress nor ATP levels in blood cells. EU regulators have not authorized any energy or antioxidant statement for CoQ10.

Amount studied: Usually 90 to 390 mg a day; 200 mg a day for two weeks in the trial of older men

EU regulators have authorized none of the CoQ10 health statements submitted to them, including statements about energy, protection from oxidative damage and endurance performance.⁹

Much of the CoQ10 research was done in people under medical care. NIH's complementary health center describes most of it as inconclusive or unsupportive, and none of it is the basis of a claim here.⁴

Ubiquinone, ubiquinol and other forms

Ubiquinone is the oxidized form of CoQ10 and the form most commonly used in supplements. The body converts it to ubiquinol to use it.⁷

Ubiquinol is the reduced form. CoQ10 appears in the blood mostly as ubiquinol even when people swallow ubiquinone.¹⁰

Two small studies in older adults disagree. A single 100 mg dose of ubiquinol was not absorbed significantly better than ubiquinone in 21 people aged 65 to 74, while two weeks of 200 mg a day raised blood levels with ubiquinol but not significantly with ubiquinone in ten older men.^7,10

CoQ10 dissolved in oil raised blood levels more than the same amount of crystalline powder in a 20-day trial in 60 healthy men, and reviews describe solubilized forms as better absorbed.^1,11,12

After a single 100 mg dose in 21 older adults, a water-soluble CoQ10 syrup was absorbed 2.4 times better than standard ubiquinone capsules.¹⁰

Taken together, how a product is formulated seems to matter at least as much as which of the two forms it uses.^10,11

How much people take

Studies have usually used 90 to 390 mg a day, against the 3 to 6 mg that food supplies. The dosage page sets out the amounts tested and what changed with them.^1,5

CoQ10 is fat-soluble and is absorbed best with fat, and in the trials on this page people took it with meals.^1,7,11

Food sources

Meat, fish, nuts and some oils are the richest food sources of CoQ10. Most dairy products, vegetables, fruits and cereals have much less.⁵

The body also makes its own, so food is only part of the supply. The food sources page covers which foods have the most and what cooking does.¹

What's in ours

What’s in ours

CoQ10: Coenzyme Q-10 (Ubiquinone), 200 mg per serving, from the label

Side effects, medicines, and who should ask first

No serious side effects of CoQ10 have been reported.^1,4

Doses of 100 mg a day or more have caused mild trouble sleeping in some people.^1,4

Digestive upsets can occur, including nausea, heartburn and pain in the upper stomach.^1,4

No official upper intake level exists for CoQ10. A published risk assessment found strong evidence of safety in clinical trials at intakes up to 1,200 mg a day and named that the observed safe level; its authors worked for a supplement industry trade association. An NIH summary reports no serious toxicity.^1,13

Ask your pharmacist or doctor first

CoQ10 may make the blood thinner warfarin less effective. The warfarin label lists coenzyme Q10 among products that may decrease warfarin's effects and advises more frequent INR checks when starting or stopping them. NIH's complementary health center and MedlinePlus also list the interaction.^1,3,4,14

On the medicine's label

Your doctor may want to check on you

CoQ10 may interact with insulin. An NIH summary says it can lower the amount of insulin people with diabetes need, so tell whoever prescribes your insulin before starting it.^1,4

Expected from how the two work, not shown in studies

NIH's complementary health center also says CoQ10 may not be compatible with some types of cancer treatment.⁴

Ask first if you take warfarin or another blood thinner
Ask first if you use insulin or other medicines that lower blood sugar
Ask first if you are being treated for cancer
If you take a statin and have muscle pain, see your prescriber before changing anything
Ask first if you are pregnant or nursing, under 18, or have trouble sleeping

Questions people ask

What does CoQ10 do for men?

No benefit specific to men has been shown. Several of the blood level trials were done only in men, such as a two-week trial in ten older men and a 20-day trial in 60 healthy men, and a 2025 review called for studies that compare the sexes.^2,7,11

Will CoQ10 give me more energy?

That cannot be promised. CoQ10 is part of how cells make energy, but studies in healthy adults show at most small, inconsistent effects on exercise performance and only hints of less fatigue. If you are short of energy most days, see a doctor to look for a cause.²

Is CoQ10 good for the heart?

No heart claim is made here. The heart research on CoQ10 was done in people under medical care, and NIH's complementary health center describes it as inconclusive.⁴

I take a statin. Should I take CoQ10?

Statins do lower the amount of CoQ10 in the blood. But NIH's complementary health center finds that the overall evidence does not show CoQ10 reducing muscle pain caused by statins. If you have muscle aches on a statin, talk to your prescriber, and do not stop the statin or add a supplement on your own.^4,6

Does CoQ10 really fall with age?

Yes. Tissue levels fall as people age, according to an NIH summary. Lower levels with age do not prove that topping up does anything for health, and trials in healthy adults have not shown clear benefits.^1,2

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.