Can CoQ10 cause dizziness? Whilst coenzyme Q10 (CoQ10) is generally well-tolerated, dizziness is among the reported adverse effects in some individuals. CoQ10, a naturally occurring compound involved in cellular energy production and antioxidant protection, is widely available as a food supplement in the UK. Although serious side effects are rare, understanding the potential link between CoQ10 and dizziness—including mechanisms such as blood pressure reduction and individual sensitivity—can help you use this supplement safely and recognise when medical advice is needed.

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 participates in the electron transport chain to generate adenosine triphosphate (ATP), the primary energy currency of cells. CoQ10 also functions as an antioxidant, protecting cell membranes and lipoproteins from oxidative damage caused by free radicals.

The body produces CoQ10 naturally, with the highest concentrations found in organs with high metabolic demands, such as the heart, liver, kidneys, and pancreas. Production may decline with age, though individual variations exist. Certain medical conditions may also be associated with altered CoQ10 levels. Statin medications, commonly prescribed to lower cholesterol, can reduce plasma CoQ10 concentrations, though the clinical significance of this remains uncertain. It's worth noting that NICE does not recommend CoQ10 supplementation for managing statin-associated symptoms.

CoQ10 is available in the UK as a food supplement (not an MHRA-licensed medicine) in two main forms: ubiquinone (the oxidised form) and ubiquinol (the reduced form). Some evidence suggests ubiquinol may have better absorption, though the clinical relevance of this difference is not well established. Typical supplemental doses range from 30mg to 200mg daily, though higher doses may be used under medical supervision for specific circumstances. While CoQ10 supplements are widely used, the evidence for specific health benefits remains limited, and they are not approved for treating or preventing any medical condition.

Why Might CoQ10 Lead to Dizziness in Some People?

Whilst CoQ10 is generally well-tolerated, dizziness is among the reported adverse effects, though it occurs relatively infrequently. The exact mechanism by which CoQ10 might cause dizziness is not fully established, but several plausible explanations exist.

Blood pressure reduction represents one potential mechanism. Some clinical studies and meta-analyses have shown CoQ10 to have a modest hypotensive (blood pressure-lowering) effect, particularly in individuals with hypertension. This effect is typically small—around 3-5 mmHg systolic in most studies. In susceptible individuals—especially those already taking antihypertensive medications or those with baseline low blood pressure—this additional reduction could precipitate orthostatic hypotension (a drop in blood pressure upon standing, typically ≥20/10 mmHg within 3 minutes), manifesting as dizziness or light-headedness.

Another consideration involves individual sensitivity and dosage. Higher doses of CoQ10 may be more likely to produce side effects, including dizziness. The relationship between CoQ10 and neurological function is complex and not fully understood.

Gastrointestinal effects may also play an indirect role. CoQ10 can occasionally cause mild gastrointestinal disturbances such as nausea or stomach upset, which some people may experience alongside or interpret as dizziness. Additionally, the timing of supplementation—particularly if taken on an empty stomach—may influence tolerability.

It is important to note that there is no official, well-established causal link between CoQ10 and dizziness in the majority of users. Most clinical trials report CoQ10 as having a good safety profile, with serious adverse events being rare. However, individual responses to supplements vary considerably.

What to Do If You Experience Dizziness While Taking CoQ10

If you develop dizziness after starting CoQ10 supplementation, several practical steps can help you manage the symptom and determine whether the supplement is responsible.

First, consider temporarily discontinuing the supplement to see if symptoms resolve. If dizziness improves within a few days of stopping CoQ10, this may suggest a connection, though it does not definitively prove causation. Do not rechallenge if you experienced severe symptoms such as fainting, severe headache, or neurological symptoms.

Review your dosage and timing. If you are taking a high dose (above 200mg daily), consider reducing to a lower amount. Taking CoQ10 with food, particularly meals containing some fat, can improve absorption and may reduce gastrointestinal side effects that could contribute to dizziness. Dividing the daily dose into two smaller doses taken at different times may also improve tolerability.

Monitor your blood pressure if you have access to a validated home monitor. Measure after sitting quietly for 5 minutes, then again within 1-3 minutes of standing. If readings are consistently lower than your usual baseline, particularly if you experience dizziness upon standing, this could indicate that CoQ10 is contributing to hypotension. Importantly, do not adjust any prescribed medications yourself—always consult your GP first.

Seek urgent medical attention if you experience:

• Sudden severe headache

• Face, arm or leg weakness, numbness or tingling (especially on one side)

• Slurred speech or difficulty finding words

• Sudden vision changes

• Fainting or collapse

• Severe chest pain or palpitations

For these symptoms, call 999 immediately as they could indicate a serious condition requiring emergency care.

Consult your GP or pharmacist for less urgent but persistent dizziness, especially if you are taking multiple medications that might interact with CoQ10 or have underlying cardiovascular or neurological conditions. They can help determine whether CoQ10 is the likely cause and advise on safe continuation or alternative approaches.

Who Should Avoid CoQ10 or Use It with Caution?

Whilst CoQ10 is considered safe for most adults, certain groups should exercise caution or avoid supplementation without medical guidance.

Individuals taking anticoagulant medications, particularly warfarin, should use CoQ10 cautiously. There have been reports—though inconsistent—of CoQ10 potentially reducing warfarin's anticoagulant effect. If you take warfarin, discuss CoQ10 with your GP or anticoagulation clinic before starting, and ensure your INR (international normalised ratio) is monitored more frequently when starting or stopping supplementation. While there is limited evidence regarding direct oral anticoagulants (DOACs), it is prudent to discuss any supplement use with your healthcare provider.

People with low blood pressure or those taking antihypertensive medications should be aware of CoQ10's potential to further lower blood pressure. This includes individuals on beta-blockers, ACE inhibitors, calcium channel blockers, or diuretics. Medical supervision is advisable to monitor blood pressure.

Pregnant and breastfeeding women should avoid CoQ10 supplements unless specifically recommended by a healthcare professional, as there is insufficient evidence regarding safety in these populations. The same precaution applies to children, for whom appropriate dosing and safety data are limited.

Individuals with diabetes should be aware that CoQ10 may affect blood glucose levels, though evidence is mixed. If you have diabetes and choose to take CoQ10, monitor your blood glucose more frequently when starting supplementation and discuss with your healthcare team.

Those undergoing cancer treatment should consult their oncologist before taking CoQ10, as its antioxidant properties could theoretically interfere with certain treatments. Do not start any supplements during cancer treatment without oncologist approval.

If planning surgery, inform your surgical and anaesthetic team about all supplements you take, as many are recommended to be stopped before planned procedures.

Any suspected adverse reactions to CoQ10 or other supplements can be reported through the MHRA Yellow Card scheme, which helps monitor the safety of healthcare products in the UK.

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