Can CoQ10 cause heart palpitations? This question concerns many people considering or currently taking coenzyme Q10 supplements. Whilst CoQ10 is widely used for various health purposes, including heart conditions and statin-related muscle discomfort, some individuals report experiencing palpitations after starting supplementation. However, there is no established causal link between CoQ10 and heart palpitations in medical literature. This article examines the evidence, explores why some people may experience palpitations whilst taking CoQ10, identifies who should exercise caution with supplementation, and clarifies when medical advice is necessary for palpitations.

What Is CoQ10 and How Does It Work in the Body?

Coenzyme Q10 (CoQ10), also known as ubiquinone, is a naturally occurring compound found in virtually every cell of the human body. It plays a crucial role in cellular energy production within the mitochondria—the powerhouses of our cells—where it facilitates the conversion of nutrients into adenosine triphosphate (ATP), the primary energy currency used by cells.

Beyond its role in energy metabolism, CoQ10 functions as an antioxidant, protecting cells from oxidative damage caused by free radicals. The body produces CoQ10 naturally, with the highest concentrations found in organs with high energy demands, including the heart, liver, kidneys, and pancreas. However, endogenous production declines with age, and certain medications—particularly statins used to lower cholesterol—may lower circulating CoQ10 levels, though the clinical significance of this reduction remains unclear.

Reasons people may consider CoQ10 supplements include:

• Heart conditions, particularly heart failure (though evidence is mixed and it is not routinely recommended by NICE or the NHS)

• Muscle discomfort associated with statin therapy (evidence is insufficient for routine use)

• Migraine management (limited evidence for prevention)

• Supporting mitochondrial function in certain genetic conditions

• General antioxidant support

CoQ10 is available in two forms: ubiquinone (the oxidised form) and ubiquinol (the reduced, active form). While ubiquinol may show higher bioavailability in some studies, the clinical advantage over ubiquinone remains uncertain. Typical supplemental doses range from 100 to 300 mg daily. As a fat-soluble substance, CoQ10 is best absorbed when taken with meals containing dietary fats.

It's important to note that in the UK, CoQ10 is regulated as a food supplement, not a licensed medicine. Always discuss with your GP or pharmacist before starting any supplement, particularly if you have existing health conditions or take prescribed medications.

Why Some People Experience Palpitations With CoQ10

Heart palpitations—the sensation of a racing, fluttering, or pounding heartbeat—are occasionally reported by individuals taking CoQ10 supplements, though there is no established causal link between CoQ10 supplementation and palpitations in the medical literature. The relationship is unclear and reports are relatively rare.

While some have theorised that CoQ10's effects on cellular energy might influence cardiac function, this remains speculative and unproven. In clinical trials examining CoQ10 for various conditions, palpitations have not emerged as a common adverse effect.

When considering palpitations while taking CoQ10, remember:

• Coincidental timing: Palpitations are common in the general population and may occur independently of CoQ10 use but be attributed to the supplement due to temporal association

• Formulation additives: Other ingredients in supplement preparations, such as caffeine or stimulants, may be the actual culprits

• Individual variation: Responses to supplements vary considerably between individuals

• Timing of administration: Taking CoQ10 late in the day may contribute to insomnia in some people, which could indirectly affect heart rhythm perception

Common non-supplement causes of palpitations include:

• Caffeine, alcohol, or nicotine consumption

• Stress, anxiety, or panic attacks

• Dehydration or electrolyte imbalances

• Anaemia

• Thyroid disorders (particularly overactive thyroid)

• Certain medications

• Underlying heart conditions

If you experience new or worsening palpitations after starting CoQ10, it is reasonable to discontinue the supplement and consult your GP. This is particularly important if you have pre-existing heart disease or are taking medications such as anticoagulants or antiarrhythmics.

Who Should Avoid or Use Caution With CoQ10 Supplements?

Whilst CoQ10 is generally considered safe for most adults, certain individuals should exercise caution or consult their GP or specialist before commencing supplementation. Understanding potential interactions and contraindications is essential for safe use.

Individuals taking anticoagulant medications, particularly warfarin, should use CoQ10 with caution. CoQ10's chemical structure is similar to vitamin K, which plays a role in blood clotting. There have been reports of CoQ10 potentially reducing warfarin's anticoagulant effect. Patients on warfarin should consult their anticoagulation clinic before starting or stopping CoQ10 and arrange additional INR (International Normalised Ratio) monitoring after any changes.

People with diabetes or those taking antihypertensive medications should also proceed cautiously. CoQ10 may have modest effects on blood glucose and blood pressure in some individuals, which could potentially affect medication requirements. Regular monitoring of blood glucose and blood pressure is advisable when initiating CoQ10 in these populations.

Pregnant and breastfeeding women should avoid CoQ10 supplements unless specifically recommended by their healthcare provider, as there is insufficient evidence regarding safety in these populations. Similarly, children should only take CoQ10 under medical supervision for specific diagnosed conditions.

Additional considerations include:

• Individuals undergoing cancer treatment should discuss any supplement use with their oncology team, as antioxidants could theoretically interact with certain treatments

• Those with a history of cardiac arrhythmias should inform their cardiologist before starting CoQ10

• People scheduled for surgery should follow their pre-operative team's guidance; many UK hospitals advise stopping non-essential supplements 1-2 weeks before surgery

When purchasing CoQ10 supplements, choose products from reputable UK retailers, avoid combination products with stimulants, and do not exceed the recommended dose on the label. If you experience any adverse effects, report them to the MHRA Yellow Card scheme, which monitors the safety of supplements and medicines.

When to Seek Medical Advice About Heart Palpitations

Whilst occasional palpitations are common and often benign, certain features warrant prompt medical evaluation. Understanding when palpitations require professional assessment is crucial for patient safety, regardless of whether they are potentially related to CoQ10 supplementation.

Seek urgent medical attention (call 999 or attend A&E) if palpitations are accompanied by:

• Chest pain, pressure, or tightness

• Severe shortness of breath or difficulty breathing

• Dizziness, light-headedness, or loss of consciousness

• Sudden, severe weakness or inability to move

• Confusion or altered mental state

• Palpitations during pregnancy or in the postpartum period

• Palpitations that occur during physical exertion and cause fainting

These symptoms could indicate serious cardiac conditions such as myocardial infarction, severe arrhythmia, or other life-threatening emergencies requiring immediate intervention. If unsure about the urgency, contact NHS 111 for advice.

Contact your GP or arrange a routine appointment if:

• Palpitations are new, persistent, or increasing in frequency

• Episodes last longer than a few minutes

• Palpitations are associated with unusual fatigue, reduced exercise tolerance, or ankle swelling

• You have a personal or family history of heart disease or sudden cardiac death

• Palpitations began after starting a new medication or supplement, including CoQ10

Your GP will typically conduct a thorough history and examination, which may include checking your pulse, blood pressure, and listening to your heart. Investigations that may be arranged include:

• 12-lead electrocardiogram (ECG) to assess heart rhythm and identify any abnormalities

• Blood tests including full blood count, thyroid function, electrolytes, and glucose to identify metabolic causes

• Holter monitor (24-48 hours) if symptoms occur daily, or longer monitoring with an event recorder if symptoms are less frequent

• Echocardiogram if structural heart disease is suspected

If you suspect CoQ10 is causing palpitations and you've purchased it over-the-counter, it is reasonable to stop taking it while awaiting medical advice. However, if CoQ10 was recommended by a specialist, discuss with them before discontinuing. Never stop prescribed medications without consulting a healthcare professional.

Frequently Asked Questions