Coenzyme Q10 (CoQ10) is a naturally occurring antioxidant that supports cellular energy production and vascular health. Some men with erectile dysfunction (ED) consider CoQ10 supplementation, hoping its effects on blood vessel function might improve erectile performance. However, whilst the biological rationale is plausible, clinical evidence supporting CoQ10 for erectile dysfunction remains limited and inconclusive. Currently, CoQ10 is not recommended by NICE or approved by the MHRA for treating ED. Men experiencing erectile difficulties should consult their GP for proper assessment and evidence-based treatments, as ED can signal underlying cardiovascular or metabolic conditions requiring medical attention.

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 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, helping to protect cells from oxidative damage caused by free radicals. This antioxidant capacity is particularly important for tissues with high metabolic demands, such as the heart, liver, kidneys, and vascular endothelium. The body produces CoQ10 naturally, but levels tend to decline with age, and certain medications—most notably statins used for cholesterol management—can reduce endogenous production.

CoQ10 exists in two forms: ubiquinone (the oxidised form) and ubiquinol (the reduced, active antioxidant form). Both forms are interconvertible within the body. Dietary sources include oily fish, organ meats, and whole grains, though the amounts obtained through diet alone are typically modest. In the UK, CoQ10 is classified as a food supplement, not a licensed medicine, and is widely available over-the-counter with various health claims including cardiovascular support, energy enhancement, and mitochondrial function.

The biological rationale for CoQ10 supplementation centres on its dual role in energy production and oxidative stress reduction—both mechanisms that theoretically could influence vascular health and, by extension, erectile function. However, it is important to distinguish between physiological plausibility and clinical evidence when considering its use for specific conditions.

The Link Between CoQ10 and Erectile Dysfunction

Erectile dysfunction (ED) is defined as the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It affects a significant proportion of men, particularly those over 40, and is often multifactorial in origin. The most common underlying cause is vascular insufficiency—impaired blood flow to the penile arteries due to endothelial dysfunction, atherosclerosis, or other cardiovascular pathology.

The proposed link between CoQ10 and erectile function is primarily based on its effects on vascular endothelial health. Healthy endothelial function is essential for the production of nitric oxide (NO), a key signalling molecule that promotes vasodilation and increased blood flow to the penis during sexual arousal. Oxidative stress impairs endothelial function and reduces NO bioavailability, contributing to ED. Because CoQ10 has antioxidant properties and supports mitochondrial energy production in endothelial cells, it has been hypothesised that supplementation might improve vascular function and, consequently, erectile performance.

Additionally, many men with ED have comorbid conditions such as diabetes, hypertension, and hyperlipidaemia—all of which are associated with increased oxidative stress and reduced CoQ10 levels. Statin therapy, commonly prescribed for cardiovascular risk reduction, may reduce CoQ10 levels. While some observational studies have suggested an association between statins and erectile difficulties, other evidence indicates statins may actually improve endothelial function and potentially benefit erectile function. Importantly, patients should never stop prescribed statin therapy without consulting their doctor.

It is important to note that there is no official link established by regulatory bodies such as the MHRA or NICE between CoQ10 supplementation and the treatment of erectile dysfunction. The theoretical mechanisms are biologically plausible, but clinical evidence is required to substantiate any therapeutic claims.

Evidence for CoQ10 in Treating Erectile Dysfunction

The clinical evidence supporting CoQ10 for erectile dysfunction remains limited and inconclusive. While several small studies have explored this relationship, robust, large-scale randomised controlled trials (RCTs) are lacking, and current data do not support routine use of CoQ10 as a primary treatment for ED.

Some preliminary research has suggested potential benefits in men with ED related to diabetes or cardiovascular factors, but these studies generally have significant methodological limitations, including small sample sizes, lack of adequate controls, and short follow-up durations. The quality of evidence is insufficient to draw firm conclusions about efficacy.

Systematic reviews and meta-analyses examining CoQ10 for various cardiovascular outcomes have shown some benefit for endothelial function and blood pressure reduction, which could theoretically translate to improved erectile function. However, these studies were not designed to assess ED as a primary outcome, and extrapolation of cardiovascular benefits to sexual health requires caution.

Currently, NICE guidance does not recommend CoQ10 for the management of erectile dysfunction. First-line treatments remain phosphodiesterase type 5 (PDE5) inhibitors such as sildenafil, tadalafil, and vardenafil, which have extensive evidence supporting their efficacy and safety. The European Medicines Agency (EMA) and MHRA have not approved CoQ10 for ED, and it remains classified as a food supplement rather than a licensed medicine.

Patients considering CoQ10 should be informed that while it is generally well-tolerated, there is insufficient evidence to support its use as a standalone or adjunctive treatment for erectile dysfunction at this time.

How to Use CoQ10 for Erectile Dysfunction Safely

For individuals who wish to try CoQ10 supplementation—whether for general health or in the hope of improving erectile function—it is important to do so safely and with realistic expectations. Typical supplemental doses range from 100 to 200 mg daily, though some studies have used higher doses (up to 300 mg per day). CoQ10 is fat-soluble, so absorption is enhanced when taken with meals containing dietary fat.

CoQ10 is generally considered safe and well-tolerated. Common side effects, when they occur, are mild and may include gastrointestinal symptoms such as nausea, diarrhoea, or abdominal discomfort. Rarely, individuals may experience headache, dizziness, or insomnia. Allergic reactions are uncommon but possible. Patients should report any suspected side effects to the MHRA Yellow Card Scheme.

Important considerations include potential drug interactions. CoQ10 may reduce the effectiveness of warfarin, necessitating closer monitoring of INR in patients on this therapy. Evidence for interactions with direct oral anticoagulants (DOACs) is limited and uncertain. Men taking antihypertensive medications should be aware that CoQ10 might have additive blood pressure-lowering effects. Additionally, while CoQ10 supplementation is sometimes recommended for individuals on statins to mitigate muscle-related side effects, evidence for this indication is also limited.

Before starting CoQ10, men with erectile dysfunction should consult their GP or a healthcare professional. ED can be an early marker of cardiovascular disease, diabetes, or other serious health conditions that require investigation and management. Self-treatment with supplements may delay appropriate diagnosis and evidence-based therapy.

Quality and regulation of supplements vary. In the UK, CoQ10 products are not subject to the same rigorous standards as licensed medicines. Patients should choose reputable brands and be cautious of exaggerated marketing claims. It is also worth noting that CoQ10 supplements can be costly, and given the lack of strong evidence for ED, the cost-benefit ratio may not be favourable.

Other Treatment Options for Erectile Dysfunction

Men experiencing erectile dysfunction have access to a range of evidence-based treatments that are supported by NICE guidance and have demonstrated efficacy in clinical trials. The first step is a thorough assessment by a GP to identify underlying causes, assess cardiovascular risk (using tools such as QRISK), and exclude serious pathology. Initial investigations may include blood pressure measurement, HbA1c or fasting glucose, lipid profile, and morning total testosterone if low libido accompanies ED.

Phosphodiesterase type 5 (PDE5) inhibitors are the first-line pharmacological treatment for ED. These include:

• Sildenafil (Viagra)

• Tadalafil (Cialis)

• Vardenafil (Levitra)

• Avanafil (Spedra)

These medications work by enhancing the effects of nitric oxide, promoting smooth muscle relaxation and increased blood flow to the penis. They are effective in approximately 70% of men and are generally well-tolerated. Common side effects include headache, flushing, nasal congestion, and dyspepsia. PDE5 inhibitors are contraindicated in men taking nitrates or riociguat due to the risk of severe hypotension. Caution is also needed when used with alpha-blockers; dose separation or starting at a lower dose may be recommended.

For men in whom oral medications are ineffective or contraindicated, second-line options include:

• Intracavernosal injections (e.g., alprostadil)

• Intraurethral therapy (alprostadil pellets)

• Vacuum erection devices

• Penile prostheses (surgical option for refractory cases)

Lifestyle modifications are also crucial and may improve erectile function independently or enhance the effectiveness of medical treatments. These include:

• Smoking cessation

• Weight loss and regular physical activity

• Moderation of alcohol intake

• Optimisation of diabetes and cardiovascular risk factors

• Psychological support or psychosexual therapy where appropriate

NICE recommends that men with ED should be assessed for cardiovascular risk factors, as ED often shares common pathophysiology with coronary artery disease. Referral to urology or specialist sexual health services may be appropriate in complex cases, suspected hypogonadism (requiring endocrinology input), Peyronie's disease, or when first-line treatments fail.

Patients should be encouraged to discuss their symptoms openly with healthcare professionals. Effective, safe, and affordable treatments are available, and early intervention can significantly improve quality of life and may identify important underlying health conditions.

Frequently Asked Questions