Coenzyme Q10: what are the real benefits for the body?

Present in every one of our cells, coenzyme Q10 is one of the most studied molecules in functional nutrition. It is also one of the most oversold. A simple search for “Q10 benefits” brings up a stream of promises regarding the heart, energy, skin, or longevity, often associated with coenzyme Q10 supplements. However, the scientific reality is more nuanced, and often more interesting. What Q10 does in the body is solidly established. What supplementation actually contributes is still the subject of research.

Understanding the benefits of Q10 means distinguishing between three levels: the proven physiological role, the avenues explored by studies, and the criteria that ensure a supplement truly delivers on its formulation promises.

Often mentioned, rarely well understood, coenzyme Q10 is a molecule that the body produces itself, and whose structure explains both its central role in cells and its difficulty of absorption.

Coenzyme Q10 is not a vitamin in the strict sense. The body synthesizes it itself, mainly from tyrosine and the mevalonate pathway. Its other name, ubiquinone, comes from the word “ubiquity”: it is found in almost all the body's cells. Identified in the late 1950s, it quickly interested researchers for its unique place in energy metabolism.

The “10” in its name refers to the ten isoprene units that make up its lipid tail. It is this structure that allows it to lodge itself in the heart of cell membranes, and which also explains its difficulty in being absorbed.

Q10 exists in two states: ubiquinone is its oxidized form, while ubiquinol is its reduced form, which exerts antioxidant activity. These are not two competing molecules, but two sides of the same cycle: Q10 is constantly shifting from one to the other during cellular reactions.

Concretely, the ubiquinone provided by diet or a supplement is largely converted into ubiquinol after absorption. In the blood, Q10 circulates primarily as ubiquinol. The debate over the “best form” is therefore less decisive than is claimed: the quality of the formulation weighs at least as much as the initial molecular form.

The highest concentrations are found in organs with high energy consumption: the heart, liver, kidneys, and skeletal muscles. This distribution is not coincidental. It directly reflects the primary function of Q10, closest to the cell's energy powerhouses.

If coenzyme Q10 attracts so much interest, it is first and foremost for its place at the heart of the mitochondria, where it links cellular energy production to defense against oxidative stress.

The mitochondria produce most of the ATP, the molecule that fuels cellular function. This production relies on the respiratory chain, a succession of protein complexes that transfer electrons. Coenzyme Q10 occupies a strategic position: it receives electrons from complexes I and II, and then transfers them to complex III.

In other words, Q10 is the mobile carrier that connects the steps of the chain. Without it, the production of cellular energy cannot proceed normally. It is this role, well-established in biochemistry, that forms the basis for the interest in the benefits of Q10.

In its ubiquinol form, Q10 is one of the rare fat-soluble antioxidants produced by the body. It acts directly in the membranes, where lipids are particularly exposed to oxidative stress. It also participates in the recycling of vitamin E, another membrane antioxidant. This antioxidant network extends to vitamin C, which itself contributes to regenerating vitamin E.

This dual role, energetic and antioxidant, is not fortuitous. The respiratory chain is both the site of energy production and one of the main sources of free radicals in the cell.

Coenzyme Q10 production is not constant throughout life: age and certain prescriptions, such as statins, are among the factors that can lower its levels.

Endogenous Q10 production declines with age. A landmark study (Kalén et al., 1989), based on the analysis of human tissues taken at different ages, highlighted a marked decrease in tissue concentrations. In cardiac muscle, this decrease is about half between the ages of 20 and 80.

This decline does not mean that everyone lacks Q10 after a certain age. However, it explains the growing interest in the molecule in nutritional approaches to cellular aging.

Statins inhibit a key enzyme in the mevalonate pathway, HMG-CoA reductase. This pathway produces both cholesterol and Q10. A meta-analysis of controlled trials (Banach et al., 2015) confirmed that taking statins is accompanied by a decrease in blood Q10 concentrations.

However, the question of the value of supplementation remains open. Meta-analyses concerning muscle discomfort sometimes reported while taking statins reach divergent conclusions. Therefore, any decision should be made by the prescribing physician.

Intense physical exertion, smoking, or certain very restrictive diets are sometimes cited as factors for a decrease. However, the available data are less robust than for age and statins. They are more a matter of hypothesis than established fact.

Aging is also observed at the cellular level: by declining with age, mitochondrial efficiency places coenzyme Q10 at the heart of scientific approaches to cellular aging.

The scientific framework of the “hallmarks of aging” (López-Otín et al., 2023) identifies twelve biological mechanisms that characterize aging. Mitochondrial dysfunction is one of them: with age, mitochondria produce energy less efficiently and generate more oxidative stress.

Q10 sits exactly at the intersection of these two phenomena. This is why it occupies a central place in longevity approaches, which target the mechanisms of aging rather than just its visible manifestations. Biocyte, one of the pioneers of nutricosmetics in France, has built its Health range on this biological understanding.

Two uses must be distinguished. In cosmetics, Q10 is applied topically in creams. In nutricosmetics, it is supplied orally and must reach the skin through the circulation.

Regarding oral use, a randomized, double-blind, placebo-controlled trial (Žmitek et al., 2017) followed volunteers for 12 weeks, at 50 or 150 mg per day. The researchers observed an improvement in certain measured skin parameters, such as micro-relief and wrinkle depth, especially at the higher dose. These results are promising, but remain to be confirmed in larger study populations.

In nutricosmetics, Q10 is thus integrated into anti-aging and firming programs, alongside active ingredients such as collagen or hyaluronic acid.

The table below summarizes the state of knowledge on the main studied benefits of Q10.

The heart is the organ richest in Q10, reflecting its constant energy demand. The most cited studies, such as the Q-SYMBIO trial (Mortensen et al., 2014), were conducted with patients being followed in cardiology. This trial involved 420 participants, at 300 mg per day for two years.

These conditions relate to medical follow-up, not dietary supplementation. The results, while encouraging but debated, cannot be transposed to the general population.

A double-blind, placebo-controlled, crossover trial (Mizuno et al., 2008) was conducted on 17 healthy volunteers subjected to an exercise bike test. It observed a modest improvement in performance and perceived fatigue at 300 mg per day. Other studies do not find these effects. The subject therefore remains open, and the doses tested often exceed those of common supplements.

Research is also looking at Q10 in the neurological sphere or in the field of fertility. These studies generally concern targeted, medically supervised populations. The data remain too heterogeneous to draw general conclusions.

In Europe, a dietary supplement can only claim a health benefit after validation by EFSA, the European Food Safety Authority. Having received several dossiers on Q10 (energy, cardiac function, antioxidant effect), it concluded in 2010 that the evidence provided did not allow for the establishment of a cause-and-effect relationship.

This finding does not mean that Q10 is useless. It means that its benefits are not demonstrated at the level of rigor required for an official claim. This is why a rigorous brand relies on associated vitamins, whose benefits are recognized, rather than on unvalidated promises.

Before turning to a supplement, it is useful to know where to find coenzyme Q10 on the plate, and what quantities diet can actually provide.

Foods rich in Q10 are primarily of animal origin. It is found in organ meats (heart, liver), meats, and fatty fish such as sardines, mackerel, or herring. Some vegetable oils (soy, rapeseed) and oilseeds (peanuts, pistachios, walnuts) also provide it. Vegetables, such as spinach or broccoli, contain only small amounts.

Average dietary intake is estimated at a few milligrams per day, on the order of 3 to 5 mg according to a reference Danish study (Weber et al., 1997). In healthy adults, endogenous synthesis covers most needs.

The quantities studied in clinical trials, from 100 to 300 mg per day, are on the other hand beyond the reach of diet alone. This is where the benefit of a supplement lies.

Faced with formulas that show similar dosages, the difference is played out elsewhere: in bioavailability, associated active ingredients, and conditions of intake—three criteria that determine what a coenzyme Q10 supplement actually provides.

Most supplements provide between 30 and 200 mg of Q10 per day, and 100 mg is a frequent benchmark. A high dosage guarantees nothing if the molecule is poorly absorbed. The displayed dosage should always be read in light of the formulation, as for all antioxidant supplements.

Q10 is a large molecule insoluble in water. Its intestinal absorption is slow and limited (Bhagavan and Chopra, 2006). Studies comparing different formulations show significant differences in blood concentrations depending on how the Q10 is dispersed and delivered.

Liposomal technology addresses this constraint. It envelops the Q10 in lipid vesicles to promote its dispersion and passage into the body. For a fat-soluble molecule, bioavailability is the primary criterion of quality, even before the molecular form.

The combination of complementary active ingredients is at the heart of the nutricosmetic approach. Vitamin E contributes to the protection of cells from oxidative stress. Vitamin B2 contributes to the reduction of tiredness and fatigue and to normal energy-yielding metabolism. PQQ (pyrroloquinoline quinone) is the subject of research for its link with mitochondrial function. Vitamin C shares this claim, as detailed in our article on vitamin C and fatigue.

These combinations make Q10 the pivot of a complete formula, where each active ingredient has a defined role.

The main rule is simple: Q10 should be taken during a meal containing fat, which facilitates its absorption. The time of day matters less. Some people, however, prefer taking it in the morning or at lunch.

Studies are generally conducted over 8 to 12 weeks. Consistency of intake matters more than the time.

Q10 is generally well tolerated. The most reported side effects of Q10 are mild and infrequent digestive discomforts.

In case of medical treatment, a doctor's advice is essential before taking it. In case of pregnancy or breastfeeding, it is important to seek advice from a healthcare professional before any supplementation. Furthermore, Q10 is not recommended for children under 15 years of age.

• Kalén A, Appelkvist EL, Dallner G. Age-related changes in the lipid compositions of rat and human tissues. Lipids. 1989;24(7):579-584.
• Banach M et al. Statin therapy and plasma coenzyme Q10 concentrations: a systematic review and meta-analysis. Pharmacol Res. 2015;99:329-336.
• López-Otín C et al. Hallmarks of aging: an expanding universe. Cell. 2023;186(2):243-278.
• Žmitek K et al. The effect of dietary intake of coenzyme Q10 on skin parameters and condition. BioFactors. 2017;43(1):132-140.
• Mortensen SA et al. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO. JACC Heart Fail. 2014;2(6):641-649.
• Mizuno K et al. Antifatigue effects of coenzyme Q10 during physical fatigue. Nutrition. 2008;24(4):293-299.
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