Coenzyme Q10 (CoQ10) is a naturally occurring antioxidant that supports cellular energy production and cardiovascular health. Some men wonder whether CoQ10 supplementation might help with erectile dysfunction, particularly given its role in vascular function and energy metabolism. Whilst CoQ10's biological mechanisms are well understood, the evidence specifically examining its effectiveness for erectile dysfunction remains limited and inconclusive. NICE and NHS guidance do not currently recommend CoQ10 for managing erectile dysfunction. This article examines the available evidence, explores how CoQ10 works in the body, and outlines proven treatment options for men experiencing erectile difficulties.

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 energy metabolism, CoQ10 functions as a potent antioxidant, protecting cells from oxidative damage caused by free radicals. This antioxidant capacity is particularly important for cardiovascular health, as oxidative stress contributes to endothelial dysfunction and arterial damage. The body produces CoQ10 naturally, with highest concentrations found in organs with high energy demands such as the heart, liver, and kidneys.

However, CoQ10 levels decline with age, though the rate and clinical significance of this decline vary between individuals. Certain medications—most notably statins used for cholesterol management—can reduce serum CoQ10 levels by inhibiting the mevalonate pathway responsible for both cholesterol and CoQ10 synthesis, though the clinical relevance of this reduction remains uncertain. Other factors that may affect CoQ10 levels include chronic diseases, nutritional deficiencies, and increased oxidative stress.

In the UK, CoQ10 is classified as a food supplement and is regulated under general food law by the Food Standards Agency and local authorities. It is not a medicine licensed by the Medicines and Healthcare products Regulatory Agency (MHRA). CoQ10 is available in two main forms: ubiquinone (the oxidised form) and ubiquinol (the reduced, active form). Whilst the body can convert ubiquinone to ubiquinol, some research suggests ubiquinol may offer improved bioavailability in certain populations, though evidence is not conclusive. Dietary sources include oily fish, organ meats, and whole grains, though the amounts obtained from food are typically modest.

The Link Between CoQ10 and Erectile Dysfunction

Erectile dysfunction (ED) affects a significant proportion of men, particularly those over 40, and is characterised by the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual activity. ED is often multifactorial, with vascular, neurogenic, endocrine, and psychological causes frequently overlapping. The physiological mechanism of erection depends heavily on healthy endothelial function and adequate blood flow to the penile tissues.

The proposed connection between CoQ10 and erectile function centres on several interrelated mechanisms. Firstly, endothelial dysfunction—impairment of the inner lining of blood vessels—is a common underlying cause of ED, particularly in men with cardiovascular risk factors such as diabetes, hypertension, or hyperlipidaemia. Some research suggests CoQ10 may improve endothelial function through enhanced nitric oxide (NO) bioavailability. NO is essential for smooth muscle relaxation in penile arteries, and improvements in vascular function could theoretically benefit erectile capacity.

Secondly, oxidative stress damages vascular tissues and impairs the delicate balance of biochemical signals required for normal erectile function. CoQ10's antioxidant properties may help neutralise reactive oxygen species, potentially protecting endothelial cells and preserving vascular health. This is particularly relevant in men with metabolic syndrome or diabetes, where oxidative stress is markedly elevated.

Additionally, some researchers have suggested that mitochondrial dysfunction in penile smooth muscle cells may contribute to ED. By supporting mitochondrial energy production, CoQ10 might theoretically improve cellular function in erectile tissues. However, it is important to note that whilst these mechanisms are biologically plausible, there is no official consensus establishing CoQ10 as a proven treatment for erectile dysfunction. NICE and NHS guidance do not recommend CoQ10 for ED, and the evidence base remains limited.

Clinical Evidence: Does CoQ10 Help With Erectile Dysfunction?

The clinical evidence examining CoQ10 specifically for erectile dysfunction remains limited and inconclusive. Whilst several small studies have explored this relationship, robust, large-scale randomised controlled trials are lacking, making it difficult to draw definitive conclusions about efficacy. The available studies are generally of low quality, with small sample sizes, methodological limitations, and high risk of bias.

Some early pilot research suggested possible improvements in erectile function scores in men with low baseline CoQ10 levels, but these studies lacked adequate controls and have not been replicated in larger, well-designed trials. More recent research has focused on CoQ10's effects on endothelial function and cardiovascular health more broadly, with some studies demonstrating improvements in vascular function markers—though these were not specifically designed to assess erectile outcomes and cannot be extrapolated to ED treatment.

Some indirect evidence comes from studies examining CoQ10 in men taking statins. Since statin therapy reduces serum CoQ10 levels and has been associated with sexual dysfunction in some patients, researchers have investigated whether CoQ10 supplementation might mitigate these effects. Results have been mixed and inconclusive, with no clear evidence of benefit for ED specifically.

The evidence base is insufficient to support CoQ10 as a treatment for erectile dysfunction. NICE Clinical Knowledge Summaries and NHS guidance do not recommend CoQ10 for ED management. Men experiencing ED should first undergo proper medical assessment to identify underlying causes—such as cardiovascular disease, diabetes, hormonal imbalances, or psychological factors—which require specific, evidence-based interventions. NICE recommends cardiovascular risk assessment for all men presenting with ED, as erectile dysfunction often precedes coronary artery disease. Relying on unproven supplements may delay appropriate diagnosis and treatment of potentially serious underlying conditions.

How to Use CoQ10 for Erectile Function

For men considering CoQ10 supplementation, it is essential to first consult with a GP or healthcare professional to ensure proper evaluation of erectile dysfunction and to rule out serious underlying conditions. Self-treatment without medical assessment is not advisable, as ED can be an early warning sign of cardiovascular disease or other significant health problems requiring urgent attention.

There is no established or licensed dose of CoQ10 for erectile dysfunction. Research studies investigating CoQ10 for other conditions have used doses typically ranging from 100 to 300 mg daily, though some studies have used higher amounts. If, after appropriate medical assessment, you and your healthcare provider decide to trial CoQ10, any dosing should be individualised and guided by clinical advice. Do not exceed the dose stated on the product label unless specifically directed by a healthcare professional.

CoQ10 is fat-soluble, meaning it is best absorbed when taken with meals containing some dietary fat. Some evidence suggests that dividing the daily dose (for example, taking smaller amounts twice daily rather than once) may improve absorption and tolerability, though this has not been definitively established.

The choice between ubiquinone and ubiquinol formulations may influence bioavailability, though evidence is not conclusive. Quality varies considerably between manufacturers, so selecting products that are UK- or EU-compliant and discussing options with your pharmacist or GP is advisable.

Patience is required, as CoQ10 does not produce immediate effects. If benefits occur, they would be expected to emerge gradually over several weeks of consistent supplementation, as tissue levels increase. It is important to maintain realistic expectations, as CoQ10 is unlikely to produce significant improvements in erectile function, particularly if substantial vascular disease or other pathology is present. Regular follow-up with your healthcare provider is recommended to assess response and determine whether continuation is warranted. CoQ10 should be viewed as a potential complementary approach rather than a replacement for proven ED treatments.

Side Effects and Safety Considerations

CoQ10 is generally considered well-tolerated with a favourable safety profile when used at recommended doses. Most people experience no adverse effects, and serious side effects are rare. However, some individuals may experience mild gastrointestinal symptoms including nausea, diarrhoea, or stomach upset, particularly at higher doses. Taking CoQ10 with food and dividing doses throughout the day often minimises these effects.

Other occasionally reported side effects include headaches, dizziness, insomnia, or skin rashes, though these are uncommon. Some people report increased energy levels, which whilst generally positive, may interfere with sleep if doses are taken late in the day. There is no evidence of significant toxicity even at doses considerably higher than those typically recommended.

Drug interactions warrant consideration. CoQ10 may theoretically reduce the effectiveness of warfarin and other anticoagulants, as its chemical structure is similar to vitamin K. Patients taking warfarin or other anticoagulants must consult their GP or anticoagulation clinic before starting CoQ10 and will require more frequent INR monitoring after starting or stopping supplementation. Additionally, whilst CoQ10 is sometimes used to address statin-related muscle symptoms, patients should inform their doctor before combining these, as the evidence for benefit is uncertain.

Certain groups should exercise particular caution. Pregnant or breastfeeding women should avoid CoQ10 supplementation due to insufficient safety data. Individuals with diabetes should be aware that some evidence suggests CoQ10 may have modest effects on glycaemic control, though findings are inconsistent; blood glucose monitoring is advisable. Those with low blood pressure should note that CoQ10 may have modest blood pressure-lowering effects in some individuals.

CoQ10 is a food supplement regulated under general food law in the UK, not as a medicine by the MHRA. Quality and purity vary between products, so choosing supplements from reputable manufacturers with independent quality certification provides additional assurance. Always inform your GP and pharmacist about all supplements you are taking to avoid potential interactions with prescribed medications. If you experience any suspected side effects from CoQ10, you can report them via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.

Other Treatment Options for Erectile Dysfunction

Evidence-based treatments for erectile dysfunction are widely available and should be considered as first-line options. The most commonly prescribed medications are phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Spedra). These medications enhance the natural erectile response by increasing blood flow to the penis and are effective in approximately 70% of men. Generic sildenafil is generally available on NHS prescription when clinically appropriate; other PDE5 inhibitors may be subject to NHS restrictions and are often obtained privately.

PDE5 inhibitors are contraindicated in men taking nitrates (for angina) or riociguat (for pulmonary hypertension) due to the risk of severe hypotension. Caution is required in men taking alpha-blockers for prostate symptoms or hypertension, and in those with significant cardiovascular disease. Your GP will assess suitability and discuss potential interactions.

For men who cannot use or do not respond to PDE5 inhibitors, alternative options include vacuum erection devices, which mechanically draw blood into the penis, or intracavernosal injections of alprostadil, which directly relaxes penile smooth muscle. In more severe cases, penile prosthesis surgery may be considered.

Initial assessment for ED should include measurement of blood pressure, assessment of cardiovascular risk, and consideration of blood tests including HbA1c or fasting glucose, lipid profile, and 9 am testosterone (particularly if low libido or clinical features suggest hypogonadism). Further hormonal tests such as prolactin, luteinising hormone, and follicle-stimulating hormone may be indicated if hypogonadism is suspected.

Referral to specialist services is recommended for men with:

• Suspected or confirmed hypogonadism

• Complex endocrine, neurological, or psychological causes

• Significant penile deformity or Peyronie's disease

• Priapism (prolonged, painful erection)

• Suspected malignancy

• Failure to respond to initial treatment

Lifestyle modifications form an essential component of ED management and may improve erectile function independently or enhance the effectiveness of medical treatments. These include:

• Achieving and maintaining a healthy weight

• Regular physical exercise (at least 150 minutes of moderate-intensity activity weekly, plus muscle-strengthening activities on at least two days per week, per UK Chief Medical Officers' guidelines)

• Smoking cessation, as tobacco significantly impairs vascular function

• Moderating alcohol consumption (not exceeding 14 units per week, spread over three or more days)

• Managing stress and anxiety, potentially with psychological support or counselling

Addressing underlying conditions is crucial. Optimising control of diabetes, hypertension, and hyperlipidaemia can significantly improve erectile function. Testosterone replacement may benefit men with confirmed hypogonadism. NICE recommends cardiovascular risk assessment for all men with ED, as erectile dysfunction often precedes coronary artery disease by several years.

Men experiencing erectile dysfunction should contact their GP for proper evaluation rather than relying solely on supplements or over-the-counter products. A thorough assessment can identify treatable underlying causes and ensure access to effective, evidence-based therapies. Psychological factors, including performance anxiety, relationship issues, or depression, may also contribute and may benefit from specialist counselling or psychosexual therapy, which can be accessed through GP referral.

Frequently Asked Questions