Is There a Blood Test for CoQ10 Levels?

Yes. CoQ10 can be measured from an ordinary blood draw, and specialty labs routinely offer the test to doctors.¹ It mainly tells you what is circulating in your blood, which is a different thing from what your muscles and other organs hold. That makes it most useful for questions about change, such as whether a statin has lowered your level or a supplement has raised it, and much less useful for diagnosing a hidden deficiency.

What a CoQ10 Blood Test Measures

The standard result is total CoQ10 in plasma, the liquid part of blood. The lab spins the tube so the plasma separates from the blood cells, and the plasma is what gets measured. The same labs can also test tissue samples.² CoQ10 circulates in two forms: ubiquinol, the active form that protects cells from damage, and ubiquinone, the form left after it has done that job.³ Total CoQ10 is simply the two forms added together.⁴ Some labs also report the ratio between the two.⁵

CoQ10 is carried in the blood alongside cholesterol, so some reports give a CoQ10-to-cholesterol figure as well as the raw level.⁶ This matters because someone with high cholesterol can show a higher raw CoQ10 without having more to spare. In adults, the adjusted figure, not the raw one, was what tracked with metabolic syndrome.⁷

The sample needs careful handling. The active form turns into the used-up form quickly when a sample is exposed to air and light.⁸ So the sample must be processed carefully before testing, especially if the lab reports the two forms separately.⁹ A delayed or mishandled sample can make your CoQ10 look more “used up” than it really is. For that reason, specialty labs often ask for the plasma to be frozen or shielded from light and shipped promptly. Results come from a specialty lab, so they can take days rather than hours.

What a Normal Result Looks Like

In one group, healthy adults not taking supplements averaged about 0.9 micrograms per milliliter (µg/mL) of blood CoQ10.¹⁰ People at risk for heart disease averaged about 1.26 µg/mL before starting a statin.¹¹ Some labs instead report micromoles per liter (µmol/L), where 1 µg/mL is about 1.16 µmol/L. Check which unit your report uses before comparing to any figure you read online. A typical CoQ10-to-cholesterol figure before supplements is about 0.2 µmol/mmol.¹²

If your report is in µmol/L and you want to compare with a figure in µg/mL, divide by about 1.16. Going the other way, multiply by about 1.16.

Age matters less than you’d think. Young children and adults have similar average total CoQ10, though children’s cholesterol-adjusted levels run higher and they carry more of the active form.¹³ In people under 22, blood CoQ10 stayed steady with age, so one reference range covers that group.¹⁴

The ratio of forms adds another angle. People with heart artery disease averaged a ratio of about 26.5 active to used-up CoQ10, versus about 30.2 in people without it.¹⁵ Those averages overlap a lot from person to person, so one ratio can’t diagnose heart disease. People with hepatitis, cirrhosis and liver cancer carried noticeably more of the used-up form.¹⁶ Because the ratio doesn’t depend on cholesterol, it can be compared fairly between people with different cholesterol levels.¹⁷

If your result lands slightly outside the range, remember that reference ranges differ between labs because their methods differ. A value just below the range is not by itself a diagnosis. Check whether the lab gave a cholesterol-adjusted figure before worrying, and know that a repeat test under the same conditions is more informative than one number. A high raw level may simply reflect high cholesterol, and supplements push levels well above the normal range, which is expected.

What the Blood Test Can’t Tell You

Blood CoQ10 showed no link to the amount in muscle tissue or in white blood cells.¹⁸ So a normal blood result doesn’t rule out low CoQ10 in muscle, and a low one doesn’t prove it. In children, the share of the used-up form in muscle rises with age while blood shows a different pattern.¹⁹

True deficiency is diagnosed differently. Primary CoQ10 deficiency is a rare inherited condition where the body can’t make enough CoQ10.²⁰ It is confirmed by finding faulty copies of one of nine CoQ10-making genes on a genetic test.²¹ Measuring CoQ10 in skin cells grown from a small skin sample also helps, because those levels are clearly low.²² In those cells the share of the active form stays normal, so the total, not the ratio, is the useful clue.²³

Inherited CoQ10 deficiency usually shows up in infants and children, often with serious symptoms involving muscles, the brain or the kidneys. For an adult with general tiredness or aches, it is a very unlikely explanation.

Diet won’t fix a low reading either. Food supplies only a few milligrams daily, mostly from meat and poultry; no nutrient studied raised blood CoQ10 meaningfully; and most CoQ10 is made by the body itself.

Statins and Your CoQ10 Level

Statins block a step the body uses to make both cholesterol and CoQ10.²⁴ Because CoQ10 is built from the same starting pathway, lowering one tends to lower the other, so taking a statin lowers circulating CoQ10.²⁵

In people at risk for heart disease who were starting atorvastatin, blood CoQ10 fell from about 1.26 to 0.62 µg/mL after 30 days.²⁶ The drop was already clear after 14 days,²⁷ so a blood test does not need months to show the change. Across placebo-controlled trials, statins lowered blood CoQ10 by about 0.44 µmol/L on average.²⁸ These are group averages, so your own drop may be smaller or larger. Part of the drop also reflects lower cholesterol, since CoQ10 rides with it.

If you want to see your own drop, a baseline result before starting lets you compare later. Testing again at least two to four weeks in shows the change, and asking for the cholesterol-adjusted figure helps separate the two effects.

Supplements raise blood CoQ10 even on a statin, but whether this eases muscle aches is uncertain. A low blood reading on a statin can’t confirm that CoQ10 is behind muscle aches, so report statin muscle pain to your doctor rather than relying on a CoQ10 test. Never stop a statin on your own; discuss options like a dose or drug change with your doctor.

Checking Whether a Supplement Is Working

After 4 weeks, ubiquinone supplements raised blood CoQ10 from about 0.9 to 2.5 µg/mL.²⁹ Ubiquinol raised it further, to about 4.3 µg/mL.³⁰ In older men, ubiquinol raised total CoQ10 about 1.5-fold within 2 weeks, while ubiquinone made little difference.³¹

To time a follow-up, test before starting to get your own starting point. Retest after about two to four weeks on a steady dose, take the dose at the same time and note when you last took it, and use the same lab both times so the numbers compare.

Absorption varies, and because CoQ10 is fat-soluble, taking it with a meal helps. The form on the label, ubiquinol or ubiquinone, changes the rise. A small rise may mean switching form rather than doubling the dose.

When you read your follow-up, compare it with your own starting figure, not with an average, because the question is whether your level moved. A clear rise, often well above the earlier number, tells you the supplement is being absorbed. It does not tell you that your muscles gained CoQ10 or that your symptoms will improve.

If your level barely changed, first check that you took the product regularly and with a meal containing fat. Next look at whether the label lists ubiquinone or ubiquinol, since ubiquinol raised levels more in the studies. Discuss with your doctor whether to switch the form or product before raising the dose, and retest afterward.

Supplement CoQ10 doesn’t stay built up in blood or tissue after you stop.³² Eight months after stopping, blood levels were back to where they started.³³ Supplements also don’t switch off your body’s own CoQ10 production.³⁴

How to Get Tested

The test is usually sent to a specialty reference lab rather than run in a clinic. So ask your doctor to order it, and say why: statin, supplement monitoring or symptoms. Insurance may not cover it when the reason is checking a supplement.

Ask the office whether you need to fast, since many labs prefer it because CoQ10 travels with fats and a recent meal can affect the reading. Keep taking any supplement the way you normally do in the weeks before, and note when you last took a dose, so the result reflects your real routine. If you are on a statin, tell the doctor and lab so the result can be interpreted correctly. If your result is unexpected, ask how quickly the sample was processed.

Some services sell CoQ10 tests without a doctor. The same limits about muscle levels apply, so bring results to your doctor rather than self-adjusting medicines.

How Much CoQ10 Is Safe to Take

Strong evidence supports safety at intakes up to 1,200 mg a day.³⁵ In healthy adults, 300 to 900 mg a day for 4 weeks caused no serious side effects.³⁶ A cautious animal-based figure puts the acceptable daily intake at about 720 mg for a 60 kg person.³⁷ Data above 1,200 mg a day are too limited to call it safe.³⁸

Supplements are often sold in doses of 100 to 200 mg, well below that ceiling, so most people taking a typical dose are far under the level where evidence runs thin. A higher dose is not automatically better, and your follow-up blood test can show whether your current dose already raises your level. Check interactions with your doctor, especially with blood thinners like warfarin.

Stomach upset and soft stools were reported, but no more at high doses than with placebo.³⁹ So these complaints aren’t clearly caused by CoQ10 itself.⁴⁰⁴¹