Coenzyme Q10: How It Works, Benefits, Dosage & Scientific Evidence

This article is for informational purposes only and does not replace personalised medical advice. Always consult a healthcare professional before starting any supplement.

What is Coenzyme Q10?

Coenzyme Q10 – also known as ubiquinone or CoQ10 – is a vitamin-like, fat-soluble compound produced naturally by the human body in almost every cell. Chemically, it is a benzoquinone with a long side chain of ten isoprene units, which gives it its name: Q10.

Q10 exists in two biologically active forms:

• Ubiquinone (oxidised form): the most widely used form in food supplements
• Ubiquinol (reduced form): the active, antioxidant form that can be used directly by the body

The body can switch between the two forms depending on current metabolic needs.

How does Q10 work in the body?

Coenzyme Q10 performs two central functions in the body:

Role in energy production

Q10 is an essential component of the mitochondrial electron transport chain – the process by which our cells produce ATP (adenosine triphosphate), the body's universal energy currency. It acts as an electron carrier between protein complexes I/II and III of the respiratory chain.

Organs with particularly high energy demands – such as the heart, liver and kidneys – contain correspondingly high concentrations of Q10.

Antioxidant protection

In its reduced form (ubiquinol), Q10 acts as a fat-soluble antioxidant: it can neutralise free radicals and helps protect cell membranes and lipids from oxidative stress. Ubiquinol can also help regenerate vitamin E.

Important note: The European Food Safety Authority (EFSA) has not authorised any health claims for Coenzyme Q10 as a food supplement. The properties described below are based on the biochemical function of Q10 in the body and on research findings that cannot be directly extrapolated to food supplement use.

Which foods contain Q10?

Q10 is present in small amounts in many foods. The best natural sources include:

A balanced diet is estimated to provide approximately 2–20 mg of Q10 per day. Plant-based foods generally contain less Q10 than animal-based sources, so those following a vegan diet may have a lower dietary intake.

When does the body's Q10 production decline?

In younger years, healthy individuals can generally meet their Q10 requirements through the body's own synthesis. However, this natural production declines with age:

• From around age 20–30, synthesis begins to decrease
• By age 40, Q10 levels may already be approximately 30% lower than at age 20
• In those aged 50–60, natural production may have fallen to around 60% of youthful levels

Beyond age, other factors can also affect Q10 levels:

• Statin therapy: Statins inhibit cholesterol synthesis via the mevalonate pathway – the same pathway used to produce Q10. Statin use may therefore reduce the body's natural Q10 production. Anyone taking statins should discuss this with their doctor.
• Certain chronic conditions
• Oxidative stress (e.g. from smoking, intensive exercise, environmental factors)

Ubiquinol vs Ubiquinone – what is the difference?

Both are forms of Q10, but they differ in their bioavailability:

As we age, the body's ability to convert ubiquinone into the active ubiquinol form decreases. For people over 40, taking ubiquinol directly may therefore be more effective.

Who may benefit from a Q10 supplement?

In consultation with a doctor or pharmacist, a Q10 food supplement may be worth considering for:

• Adults over 40, whose natural production declines with age
• People taking statins, as these medications can affect Q10 synthesis
• Vegans and vegetarians, who obtain less Q10 through diet
• Those under increased oxidative stress (e.g. competitive athletes, smokers)

Important: Q10 food supplements are not medicines and are not suitable for the treatment of any medical condition. If you have health complaints or existing medical conditions, always seek medical advice.

Dosage and how to take Q10

There is no officially established recommended daily intake for Coenzyme Q10 as a food supplement in the EU. Scientific studies have examined a wide range of doses; amounts between 30 mg and 300 mg per day are commonly used.

Practical tips for taking Q10:

• Q10 is fat-soluble – taking it with a fatty meal improves absorption
• Ubiquinol is better absorbed from the gut than ubiquinone, according to studies
• Effects may only become noticeable after several weeks of regular use

For individual dosage guidance – particularly if you have existing health conditions or are taking medication – always consult a doctor or pharmacist.

Possible side effects and interactions

Coenzyme Q10 is generally considered well-tolerated at moderate doses. Known possible side effects at higher doses include:

• Nausea, diarrhoea or digestive discomfort
• Insomnia (if taken in the evening)
• Headaches

Important interactions:

• Anticoagulants (e.g. warfarin): Q10 may influence the anticoagulant effect. Anyone taking blood-thinning medication should not supplement with more than 100 mg Q10 per day without prior medical advice.
• Antidiabetic medication: There are indications of possible interactions with diabetes medications.
• Chemotherapy: Possible interactions exist; only take with oncological guidance.

Pregnancy and breastfeeding: Due to insufficient data on safety during pregnancy and lactation, pregnant and breastfeeding women should only take Coenzyme Q10 on the explicit recommendation of a doctor.

References

1. Mortensen, S. A. et al. (2014). The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure. JACC: Heart Failure, 2(6), 641–649. https://pubmed.ncbi.nlm.nih.gov/25282031/
2. European Food Safety Authority (EFSA). Register of authorised health claims. ec.europa.eu.
3. Bhagavan, H. N. & Chopra, R. K. (2006). Coenzyme Q10: Absorption, tissue uptake, metabolism and pharmacokinetics. Free Radical Research, 40(5), 445–453.
4. Littarru, G. P. & Tiano, L. (2007). Bioenergetic and antioxidant properties of coenzyme Q10. Molecular Biotechnology, 37(1), 31–37.
5. Food Standards Agency (UK). Guidance on health claims for food supplements.