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Coenzyme Q10: 8 Benefits, Side-Effects and Summary

Written on February 15, 2022

What it is | Symptoms of Deficiency | How it works | Benefits | Safety | Side effects | Dosage | How to buy | How to take | The bottom line

What it is

In every cell of the body, Coenzyme Q10 maintains your health.

It helps you create energy and is part of your body’s natural antioxidant defenses.

For the majority of people, Coenzyme 10 is not necessary to take as your body makes it.

However, certain benefits are attached to supplementation in those who have a deficiency.

Risk factors for deficiency include aging, history of heart attack, taking statins and various diseases [1][2].

Older persons may also benefit as the ability to biosynthesize Coenzyme Q10 falls with age.

Symptoms of deficiency

Primary Coenzyme 10 deficiency is a disorder that arises from genetic mutations in the COQ genes.

Key indicators of Coenzyme 10 deficiency encompass a wide range of symptoms.

Key clinical symptoms of deficiency include:

  • mitochondrial encephalopathy including hypotonia, strokes, cerebellar ataxia, spasticity, peripheral neuropathy, and intellectual disability.
  • mitochondrial encephalopathy involving myopathy, retinopathy, optic atrophy, sensorineural hearing loss, and hypertrophic cardiomyopathy
  • unexplained ataxia especially when family history suggests recessive autosomal heritage
  • exercise intolerance, with high serum creatine kinase levels accompanied by muscular weakness
  • steroid-resistant nephrotic syndrome particularly when associated symptoms of deafness, retinopathy and other neurological defects
  • Leigh syndrome accompanied with growth retardation
  • severe infantile multisystemic disease

Steroid resistant nephrotic syndrome may be the primary renal indicator.

It is commonly the initial symptom of either an isolated renal involvement or associated with encephalopathy including seizures, stroke-like conditions and intellectual disability.

In the latter, this results in early death.

In those with Primary Coenzyme 10 Deficiency, high dose supplementation can halt or reverse manifestations of disease.

Severe renal or brain damage cannot be reversed.

See [3][4] for more information regarding clinical symptoms.

How it works

Coenzyme Q10 is a crucial component of the mitochondria present in every cell.

It is involved in oxidative phosphorylation, whereby you convert energy from carbohydrates and fats into useful energy [5][6].

As the only fat soluble antioxidant you produce, Coenzyme Q10 protects you from oxidative damage from free radicals.

It also prevents lipid peroxidation and can regenerate vitamin E and C to their active form.

The antioxidant function of Coenzyme Q10 is attributed to the ubiquinol form, which is regenerated from ubiquinone form.

Most of the body’s requirement of Coenzyme Q10 is produced in the body, however it is present in some foods.

The amounts you eat in foods is limited, and depending on diet is estimated at typically 5 mg/day [7].

The daily requirement however is 500 mg.

The bulk amount of this antioxidant is produced through endogenous production.

The body contains 500-1500 mg of Coenzyme Q10, reducing with age.

Highest bio-synthesis levels occur in the mid-twenties and consists of a myriad of processes that require a wide range of vitamins, amino acids and precursors [8][9].

In addition to age, those suffering from heart disease are at a higher risk of having reduced Coenzyme Q10 levels [10].

The good news is that oral supplementation of Coenzyme Q10 products can improve levels in the body, they aren’t excreted unabsorbed [11][12][13][14][15].

However, the dosage affects where supplemental Coenzyme Q10 is detected.

At low dosages, there are minimal cognitive effects because of poor absorption into the brain.

Supplemental Coenzyme Q10 is detected in other areas of the body more readily (as Coenzyme being a fat-soluble compound is hydrophobic and fails to cross the blood-brain barrier efficiently).


1. May reduce migraines

Coenzyme Q10 may be an effective treatment for migraines, and can reduce attack frequency, headache-days and days with nausea.

In a randomized controlled trial, three doses per day of 100 mg Coenzyme Q10 had the effect of reducing migraine frequency [16].

The treatment was well tolerated.

However it took 3 months before results were evident.

Another randomized controlled trial of 122 children given 100 mg Coenzyme Q10 for 7 months failed to find any benefit [17].

However, in the early stages of the trial (weeks 1-4), there was an initial improvement in the severity of headaches.

A study examining the combination of magnesium, the feverfew plant and Coenzyme Q10 led to promising results [18].

Adults suffering from migraine taking this proprietary treatment had reduced days with headache (75% reduced their days with headache by half) after three months, and this proportion increased throughout treatment, from 63.2% in month 1 to 70.6% in month 3.

Migraines are correlated to inflammation, and Coenzyme Q10 is an anti-inflammatory compound.

In a randomised double-blind placebo-controlled trial, 45 non-menopausal women underwent treatment [19].

After a one month period, 23 subjects received Coenzyme Q10 at a dose of 400 mg/day) or placebo for three months. After this period, markers of inflammation including interleukin-6, IL-10 and TNF-a were measured.

There was a reduction in frequency, severity and duration of migraine attacks in the Coenzyme Q10 treated group compared to placebo.

A clinical trial examined the effect of Coenzyme Q10 and nano-curcumin on migraine by giving 100 men and women with episodic migraine one of four treatments [20].

The treatment of Coenzyme Q10 (300 mg)and nano-curcumin (80 mg) outperformed other groups and led to reduction in migraine frequency.

2. Possibly reduces pain associated with fibromyalgia

Fibromyalgia changes your levels of Coenzyme Q10 for the worse [21].

Whilst levels of Coenzyme Q10 are not altered in the blood, immune cells have reduced Coenzyme Q10.

In patients with fibromyalgia, oxidative stress is often observed and associated with mitochondrial dysfunction and loss of muscular function. As Coenzyme Q10 is a powerful antioxidant, it is proposed that it can protect immune cells from oxidative stress.

In a clinical trial, researchers studied 20 fibromyalgia patients and 15 control to evaluate oxidative stress levels and fibromyalgia symptoms [22].

They found decreased Coenzyme Q10 levels and an increase in lipid peroxidation levels in the blood.

After oral supplementation (300 mg/day) of Coenzyme Q10 for 3 months, inflammation and associated symptoms were reduced and normal levels of Coenzyme Q10 were restored.

It is thought that mitochondrial dysfunction and impaired cholesterol metabolism plays a role in fibromyalgia symptoms.

In a clinical trial, levels of ubiquinone-10, ubiquinol-10, free cholesterol (FC), free fatty acids (FFA) and cholesterol esters (CE) were measured in children and adolescents with fibromyalgia [23].

The initial levels of free cholesterol was significantly higher compared to control, indicating high cholesterol.

Additionally, the ratio of ubiquinone-10 to total Coenzyme Q10 was elevated relative to healthy control, whilst ubiquinol-10 in blood was significantly less than control.

This suggests that fibromyalgia is associated with Coenzyme Q10 deficiency.

When these patients were treated with Coenzyme Q10 in the form of ubiquinol-10 (100 mg/day) for 12 weeks, chronic fatigue scores improved.

As an alternative therapeutic approach for fibromyalgia, Coenzyme Q10 is a promising option [24].

It appears to be effective for physical symptoms, moreso than neurological symptoms [25].

This is echoed in the research, which suggests that Coenzyme Q10 supplementation is less able to penetrate the blood-brain barrier, and accumulates first in the blood and body.

3. For heart health

Heart disease refers to a number of conditions including arrythmia, coronary artery disease, heart failure and heart valve disease.

A general meta-analysis of 14 randomised controlled trials involving 2149 patients examined the effects of Coenzyme Q10 on cardiac health [27].

Researchers found Coenzyme Q10 failed to improve heart function, or symptoms of heart failure.

However it did lead to higher exercise capability and lowered mortality.

There was no difference in left ventricle ejection fraction between Coenzyme Q10 treated patients and placebo.

In a randomized, double-blind trial lasting 28 days, researchers found that following a heart attack, administering Coenzyme Q10 (120 mg/day) within three days can reduce irregular heartbeat and heart pain [28].

Supplementation of Coenzyme Q10 also improved levels of vitamins A, E and C following the acute heart attack.

In the group taking the placebo treatment, subsequent risks of future heart attack were double those given Coenzyme Q10.

The body needs nitric oxide to help dilate blood vessels, however the primary free radical produced by mitochondria, superoxide, readily combines to form peroxynitrite, which can result in cardiac cell death [29][30].

Coenzyme Q10 works to counteract levels of superoxide and decrease its circulation in the body [31][32].

Peroxynitrite has been implicated in atherosclerosis, inflammatory bowel disease, myocardial iscemia, septic lungs and ALS.

In studies, doses of Coenzyme Q10 ranging from 200 – 300 mg/day improved blood vessel function compared to placebo [33][34].

The benefits were attributed to the counteracting of nitric oxide oxidation. In other words, reducing superoxide activity.

4. Reduces blood pressure (in those with high blood pressure)

Over time high blood pressure may eventually cause health problems such as heart disease.

There are few studies that examine the relationship between Coenzyme Q10 and blood pressure independently.

Where co morbidities are present, they are clearly referenced.

Coenzyme Q10 has a blood pressure lowering effect, however the magnitude of the change is minute and largely isolated to those with high blood pressure.

Subjects with type 2 diabetes who were at a risk of developing heart disease were assigned 200 mg/day of Coenzyme Q10 or placebo for 12 weeks [35].

Researchers found a three-fold increase in plasma Coenzyme concentration and a reduction in systolic, diastolic blood pressure and HbA(1c).

In a clinical trial, twice daily dosages of 60 mg oral Coenzyme Q10 led to a mean reduction in systolic blood pressure of 17.8 +/- 7.3 mm Hg (mean +/- SEM) without orthostatic blood pressure changes after 12-weeks [36].

In a randomised, double-blind trial of patients receiving antihypertensive medication, coenzyme Q10 (60 mg twice daily) led to increases in HDL-cholesterol and decreases in blood pressure after 8 weeks [37].

A hydrosoluble form of Coenzyme Q10 was administered [38]. This form of Coenzyme Q10 has a higher bioavailability and appeared able to combat oxidative stress [39].

Pregnant women experience high blood pressure which can cause swelling.

A serious condition known as pre-eclampsia can lead to serious complications including seizure, and death.

In a study of 197 women at risk of pre-eclampsia, those women who took 200 mg/day Coenzyme Q10 for 20 weeks before giving birth had a lower rate (14.4% vs 25.6%) of pre-eclampsia [40].

Coenzyme Q10 supplementation can increase the incidence of blood clotting, which may be dangerous during prenancy.

If you are pregnant, it is vital to speak to a medical practitioner before taking any Coenzyme Q10 supplements.

5. Reduces blood sugar

Coenzyme Q10 may lower blood sugar in diabetics according to a meta-analysis of 14 studies [41].

Specifically, fasting blood glucose, fasting blood insulin, HbA1c and insulin resistance all decreased at a dosage of less than 200 mg/day.

Another meta-analysis of 18 studies found the blood sugar lowering effects of Coenzyme Q10 can occur in both healthy patients and those with high blood glucose levels (>6mmol/L) [42].

A randomized controlled trial failed to find any effect on blood sugar in diabetics after 12 weeks of daily supplementation at a dose of 120 mg [43].

Another randomized, placebo-controlled trial found no correlation between 100 mg Coenzyme Q10 dose and blood sugar levels [44].

A 8-week randomized, double-blind, placebo-controlled study of 80 prediabetic patients failed to find any effect on fasting blood glucose and insulin levels [45].

Despite this, it did find a reduction in the severity of insulin resistance.

In meta-analysis, the blood sugar lowering response to Coenzyme Q10 supplementation is short lived (<12 weeks) and occurs at doses around 200 mg/day or less.

However, the evidence for this is weak and a multitude of conflicting studies suggest no benefit.

More replication is required.

6. May improve fertility


In men, sperm cells rely on Coenzyme Q10 for two crucial functions.

The first being that energy for sperm movement depends on the presence of Coenzyme Q10.

The second is to protect the sperm membranes from oxidative stress, in other words, to keep them alive.

Sperm motility refers to the ability of the sperm to swim efficiently and is a marker of male fertility.

Sperm motility is important for fertility along with other factors including sperm shape and sperm count.

In those struggling with infertility, sperm motility is commonly very low.

One study examined sperm motility in vitro in 38 men who had normal sperm concentrations and morphology with a a history of infertility [46].

The men were all previously registered in an infertility clinic and were given 60 mg/day Coenzyme Q10 for 103 days.

There was a subsequently large improvement in fertilization rates from 10.3+/- 10.5% to 26.3 +/- 22.8% however this was only evident in men with low fertilization rates following unsuccessful ICSI.

Samples with normal motility did not have any improvement.

A randomized, double-blind placebo controlled clinical trial studied 47 men with unexplained low sperm count [47].

The 47 men were assigned to receive either 200 mg Coenzyme Q10 per day or placebo for 12 weeks.

No effect was found on sperm concentration, motility and morphology however there was a decrease in oxidative stress.

Another randomized controlled trial of 227 men found that Coenzyme Q10 suplementation (ubiquinol) led to higher sperm motility and density [48].

Participants were dosed 200 mg per day for 26 weeks.

These men had idiopathic infertility, meaning the cause of infertility was unknown.

A randomized controlled trial of 212 infertile men found that 300 mg Coenzyme Q10 daily for 26 weeks led to a decrease in serum luteinizing hormone and follicle-stimulating hormone [49].

Luteinizing hormone levels that are too high indicate damage to the testes or infertility.

High levels of FSH indicate fertility issues.

The supplementation of Coenzyme Q10 had an improvement on sperm motility, morphology and count.

More research is needed, especially randomized controlled trials.


In reproductive medicine, managing the ovarian reserve or poor ovarian response (POR) is a major challenge.

Managing the ovarian reserve can allow for greater success during IVF treatment.

However, there is limited evidence in treatment for women who fail to find any success in IVF treatment.

Supplementation of Coenzyme Q10 increased the availability of high-quality embryos in women suffering from poor ovarian reserve levels, leading to an increase in pregnancy rates [50].

7. Peyronie’s Disease

In men, Peyronie’s Disease is a disease where trauma to the genitals results in curvature of penis.

Other causes include collagen alternations and autoimmune disorder.

The curvature occurs as a result of scar tissue known as a plaque.

This condition is more likely to happen in men approaching middle-age, those experiencing ED and those who have had surgery for prostate cancer.

It is estimated that PD occurs in 2-8% of the population, however this figure likely understates true incidence of disease [51][52].

PD is highly stressful and can result in depression and distress [53].

Statistically, 12% of men have rapid recovery from Peyronie’s disease, 40% have stable PD and 48% worsen over time [54].

Coenzyme Q10 at doses of 300 mg/day reduced curvature of the penis, improved penis function and reduced scar tissue in a trial of 186 people [55].

8. May work synergistically with chemotherapy

A long-term study of 81 patients undergoing interferon treatment for melanoma found that Coenzyme Q10 (400 mg/day) reduced the likelihood of cancer after three years.

Long-term administration had no side effects and led to a further reduced rate of recurrence.

A systematic review found that Coenzyme Q10 may improve the tolerability of cancer treatments by protecting against chemotherapy-induced heart and liver damage [56].

Further research is necessary.


Coenzyme Q10 is HIGHLY safe at doses up to 200 mg/day.

Doses at this level have been administered for up to 2 years without adverse reactions.

However it is structurally similar to vitamin K and can interact with many drugs.

Please consult your medical practitioner before undergoing supplementation.

In particular, those taking these medications may experience unsafe effects:

  • Coenzyme Q10 can reduce the efficacy of blood thinners including Warfarin
  • Blood presssure lowering medication and Coenzyme Q10 taken together may lead to extremely low blood pressure
  • Blood sugar-lowering effects of Coenzyme Q10 can be dangerous for diabetics
  • Elixophylline, theochron or theophylline become less effective [57]

Side Effects

Coenzyme Q10 side effects are rare but include

  • nausea
  • vomiting
  • diarrhea
  • anorexia
  • allergic rash

Supplementation does not appear to be unsafe, even at doses of 1,200 mg/day [58][59].


For treatment of Primary Coenzyme Q10 deficiency, a recommended dose of 5-50 mg/kg daily is helpful.

However for those without this disease, it is recommended to stick to a dose <300 mg/day.

Despite this, no research has found adverse effects even at doses of 1200 mg.

At standard doses of 30 mg, marginal absorption occurs.

When this is increased up to a daily dose of 200 mg, this results in a significant increase in the body.

How to buy

Coenzyme Q10 is commonly sold in tablets or powders at dosages of 30-100mg per pill.

However higher dosages of 400 mg exist.

There are two common forms known as ubiquinol or ubiquinone.

It has been argued that ubiquinol is more effective, however the difference is marginal and you should not overpay for a ubiquinol supplement if you are healthy as your body can readily convert between the two [60][61].

Bio-availability is affected by other factors to a larger degree [62].

These factors include whether the Coenzyme Q10 is a water-soluble formula (these are often patented).

Water soluble formulations are more expensive, however they do appear to be marginally better in terms of absorption [63][64].

Other factors include whether or not the delivery method was a soft gel (superior), a capsule or liquid (water-soluble), or if it was taken with dietary fat.

How to take

The standard dose of Coenzyme Q10 ranges from 50-200mg per day.

The best way is to take with a fat containing meal to enhance and speed up intestinal absorption [65].

Secondarily, eating a meal increases the transmit time through the intestine, allowing more opportunity for uptake.

For young people, Coenzyme Q10 supplementation is unnecessary and is taken as an insurance policy against deficiency.

However, levels do drop as you age and supplementation is a reliable way of boosting levels.

For older people, we recommend ubiquinol as the conversion rate between ubiquinone and ubiquinol falls throughout your life.

Additionally, supplementation can be beneficial for those who are undertaking a statin treatment/have previously sustained damage to the cardiac tissue or suffer from fibromyalgia and migraines.

Ubiquinol vs Ubiquinone vs Water-soluble Formulations

The research is unclear as to whether ubiquinol offers any benefit to ubiquinone.

Conflicting evidence suggests that ubiquinol is more readily absorbed into the body and Ubiquinone does appear to be less effective than water-soluble formulations of Coenzyme Q10 in treating cognitive issues [66][67].

As you age, the conversion rate of ubiquinone to ubiquinol falls.

It is important whether Coenzyme Q10 is taken with or without a fat containing meal.

Doses taken with a meal are absorbed at rates three times those without.

The Bottom Line

The benefits of taking Coenzyme Q10 are numerous, and it is highly safe.

Make sure to take it with a meal as this helps with absorption.

Taking ubiquinol may confer additional benefits in terms of bioavailability.

When you are older, your ability to create Coenzyme Q10 is low compared to young, healthy people. For this reason, it is likely beneficial.

New formulations of Coenzyme Q10 that dissolve in water could provide cognitive benefit.

It is unclear whether supplementing Coenzyme Q10 has any enhancement on antioxidant capacity or prolongation of lifespan.