Does more sildenafil make you harder? Many men with erectile dysfunction wonder whether increasing their dose of sildenafil (Viagra) will improve erection quality. The relationship between sildenafil dosage and erectile response is not straightforward, and taking more medication does not necessarily produce better results. Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor that enhances the natural erectile response to sexual stimulation. Understanding how the medication works, the recommended dosages, and the risks of exceeding prescribed amounts is essential for safe and effective treatment. This article explains the evidence on sildenafil dosing and when to seek medical advice.

How Sildenafil Works for Erectile Dysfunction

Sildenafil, commonly known by the brand name Viagra, is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK for the treatment of erectile dysfunction (ED). The medication works by enhancing the natural erectile response to sexual stimulation rather than directly causing an erection.

When a man becomes sexually aroused, nerve signals trigger the release of nitric oxide in the erectile tissue of the penis. This chemical messenger activates an enzyme that produces cyclic guanosine monophosphate (cGMP), which relaxes the smooth muscle in the blood vessels of the penis, allowing increased blood flow. Sildenafil works by blocking the PDE5 enzyme, which normally breaks down cGMP. By inhibiting this breakdown, sildenafil helps maintain higher levels of cGMP, promoting sustained blood flow to the penis and facilitating an erection in response to sexual stimulation.

It is important to understand that sildenafil does not work without sexual arousal. The medication enhances the body's natural erectile mechanism but does not create desire or automatically produce an erection. Sildenafil typically begins working within 30 to 60 minutes of taking the tablet and its effects, or the ability to achieve an erection in response to stimulation, may persist for up to approximately 4 hours, though this varies between individuals.

The medication is absorbed through the digestive system, and factors such as food intake—particularly high-fat meals—can delay its onset of action. For optimal effectiveness, sildenafil is usually taken on an empty stomach or after a light meal, approximately one hour before anticipated sexual activity.

Does Increasing Sildenafil Dose Improve Erection Quality?

Many men wonder whether taking a higher dose of sildenafil will result in a firmer or more reliable erection. The relationship between sildenafil dose and erectile response is not straightforward, and more medication does not necessarily equate to better results.

Clinical trials have demonstrated that sildenafil shows a dose-response relationship up to a certain point. Studies indicate that increasing the dose from 25mg to 50mg, and from 50mg to 100mg, can improve erectile function in some men who do not respond adequately to lower doses. However, this improvement plateaus, and there is no evidence that exceeding the maximum recommended dose of 100mg provides additional benefit. The 100mg dose is the maximum recommended single dose in the Summary of Product Characteristics (SmPC) due to tolerability and safety considerations; higher doses are not recommended and increase adverse effects.

The effectiveness of sildenafil depends on multiple factors beyond dosage, including:

• The underlying cause of erectile dysfunction (vascular, neurological, psychological, or hormonal)

• Timing of administration relative to sexual activity

• Presence of adequate sexual stimulation

• Concurrent medications that may interact with sildenafil

• Lifestyle factors such as alcohol consumption, smoking, and overall cardiovascular health

Men taking alpha-blockers (such as doxazosin or tamsulosin) should use sildenafil with caution, as the combination may cause a significant drop in blood pressure. Ideally, sildenafil should be started only after a patient is stable on alpha-blocker therapy, with a 25mg starting dose and monitoring for postural hypotension.

For men who find their current dose ineffective, the appropriate response is not to self-increase the dose but to consult their GP or prescriber. A healthcare professional can assess whether dose adjustment is appropriate, investigate other contributing factors to ED, or consider alternative treatment approaches. Taking more than the prescribed dose increases the risk of adverse effects without guaranteed improvement in erectile function.

Recommended Sildenafil Dosages in the UK

In the United Kingdom, sildenafil is available in three standard tablet strengths: 25mg, 50mg, and 100mg. The appropriate starting dose depends on individual patient factors, including age, overall health, concurrent medications, and the severity of erectile dysfunction.

For most adult men, the recommended starting dose is 50mg, taken approximately one hour before sexual activity. This dose should not be taken more than once in a 24-hour period. Based on individual response and tolerability, the dose may be increased to a maximum of 100mg or decreased to 25mg by a healthcare professional.

For older men (aged 65 and over) or those with hepatic impairment (liver problems) or severe renal impairment (kidney problems with creatinine clearance <30 mL/min), the recommended starting dose is typically 25mg. The body's ability to metabolise and eliminate sildenafil may be reduced in these populations, meaning the medication remains in the system for longer and may have more pronounced effects. Mild to moderate renal impairment usually requires no dose adjustment.

Sildenafil is contraindicated (must not be used) in patients taking:

• Any nitrate medications (such as glyceryl trinitrate, isosorbide mononitrate/dinitrate)

• Nitric oxide donors (such as nicorandil)

• Recreational nitrates ('poppers' such as amyl nitrite)

• Riociguat (used for pulmonary hypertension)

Certain medications can affect sildenafil metabolism, particularly those that inhibit the CYP3A4 enzyme system. Men taking ritonavir, erythromycin, ketoconazole, itraconazole, or cimetidine may require dose adjustments, typically starting with 25mg. Grapefruit juice can also increase sildenafil levels and should be avoided or used with caution. Your GP or pharmacist will advise on appropriate dosing if you take these medications.

Sildenafil is usually used as needed rather than on a daily basis. The medication should be taken only when sexual activity is anticipated, and the maximum frequency is once per day. Men should allow adequate time between doses and never double up if a dose seems ineffective.

In the UK, sildenafil 50mg (Viagra Connect) can be supplied by pharmacists without a prescription following a consultation to assess suitability, for men aged 18 years and over. Other strengths and formulations still require a prescription.

Risks of Taking Higher Doses Than Prescribed

Exceeding the prescribed dose of sildenafil significantly increases the risk of adverse effects without providing additional therapeutic benefit. The side effect profile of sildenafil is dose-dependent, meaning higher doses are associated with more frequent adverse reactions.

Common side effects of sildenafil include:

• Headaches (very common, affecting more than 1 in 10 people)

• Facial flushing and feeling of warmth

• Indigestion and gastrointestinal discomfort

• Nasal congestion

• Visual disturbances, including a blue tinge to vision, increased light sensitivity, or blurred vision

• Dizziness and light-headedness

More serious risks associated with excessive sildenafil doses include cardiovascular effects. Sildenafil can cause a drop in blood pressure, which may be dangerous for men with certain heart conditions or those taking nitrate medications (such as glyceryl trinitrate for angina). The combination of sildenafil with nitrates or nitric oxide donors (including nicorandil and recreational 'poppers') can cause a severe and potentially life-threatening drop in blood pressure and is absolutely contraindicated.

Caution is needed when using sildenafil with alpha-blockers (used for prostate problems or high blood pressure). These combinations may cause significant blood pressure drops, especially when starting treatment. Separate dosing times and consider a reduced sildenafil dose (25mg).

Rare but serious adverse effects include priapism (a painful erection lasting more than four hours), sudden hearing loss, and non-arteritic anterior ischaemic optic neuropathy (NAION), a form of sudden vision loss. If you experience a prolonged erection (>4 hours), chest pain, or sudden changes in vision or hearing, stop taking sildenafil and seek immediate medical attention (A&E/999).

Taking sildenafil obtained from unregulated sources poses additional risks, as the tablets may contain incorrect doses, contaminants, or entirely different substances. The MHRA regularly warns about counterfeit erectile dysfunction medications sold online. Always obtain sildenafil through legitimate UK-registered pharmacies, either with a prescription or, for 50mg tablets only, via Viagra Connect following a pharmacist consultation.

If you experience any suspected side effects, report them through the MHRA Yellow Card scheme, which helps monitor the safety of medicines.

When to Speak to Your GP About Sildenafil Effectiveness

If you find that sildenafil is not working as expected, it is important to consult your GP or prescriber rather than increasing the dose independently. There are several situations that warrant a medical review:

Consistent lack of response: If sildenafil has not produced satisfactory results after trying it on at least 6-8 separate occasions under optimal conditions (considering timing, food intake, and level of sexual stimulation), discuss this with your doctor. They may consider adjusting the dose, investigating underlying causes, or exploring alternative treatments.

Declining effectiveness: If sildenafil initially worked well but has become less effective over time, this may indicate progression of underlying vascular disease, changes in other medications, or psychological factors. Your GP can assess whether additional investigations are needed, such as morning total testosterone levels (particularly if you have symptoms suggesting hypogonadism), glucose control (for diabetes), or lipid profiles.

Inadequate response at maximum dose: If you have tried 100mg sildenafil without adequate effect, your doctor may consider alternative PDE5 inhibitors (such as tadalafil, vardenafil, or avanafil), which have different pharmacokinetic profiles, or other treatment modalities including vacuum erection devices, intracavernosal injections, or psychological and relationship support.

New or worsening side effects: Any troublesome side effects should be reported, as dose adjustment or switching to an alternative medication may be appropriate.

Urgent medical attention is required if you experience:

• A painful erection lasting more than 4 hours (priapism)

• Sudden vision or hearing loss

• Chest pain or severe dizziness In these cases, stop taking sildenafil and seek immediate medical care (A&E/999).

Changes in overall health: New diagnoses (particularly cardiovascular conditions, diabetes, or neurological disorders), changes to other medications, or lifestyle factors (such as increased alcohol consumption or new relationship stress) can all affect erectile function and sildenafil's effectiveness.

Your GP can also ensure that erectile dysfunction is not a symptom of an underlying health condition requiring treatment. ED can be an early warning sign of cardiovascular disease, as the blood vessels in the penis are smaller than coronary arteries and may show dysfunction earlier. A holistic assessment, including cardiovascular risk factors, is an important part of ED management according to UK clinical guidance.

Frequently Asked Questions