What Is Viagra and What Does It Do?

• Genuine Viagra and sildenafil supplied through a GPhC-registered UK pharmacy
• Online consultation with UK-registered prescribers before any prescription is issued
• Clear, honest guidance on how Viagra works, what it does, and what it does not
• Straightforward, discreet access to treatment once you are assessed as suitable

Viagra is one of the most widely recognised medicine names in the world, yet a surprising amount of what people believe about it is inaccurate or incomplete. It is a prescription-only tablet used to treat erectile dysfunction (ED), and its active ingredient is sildenafil.

This guide explains what Viagra actually is, how it works in the body, what it can and can not do, and how it is obtained safely and legally in the UK. Every section below is written to stand on its own, so you can jump straight to the part you need.

If you are trying to work out whether Viagra could help you, this page covers the essentials. Only a UK-registered prescriber can confirm whether it is suitable for you, based on a proper clinical assessment of your health.

What Is Viagra?

Viagra is a branded medicine containing sildenafil citrate, an active ingredient used to treat erectile dysfunction. First licensed in the UK in the late 1990s, it was one of the earliest oral treatments of its kind and remains one of the best known medicines in the world.

The Active Ingredient: Sildenafil

Every Viagra tablet contains sildenafil as its active ingredient. Sildenafil is the active drug in Viagra, and it is also used to treat pulmonary arterial hypertension under the brand name Revatio. Sildenafil belongs to a group of medicines called PDE5 inhibitors, which all work in broadly the same way to support erectile function. Other PDE5 inhibitors are also available on prescription in the UK, including tadalafil and vardenafil, each with slightly different timing and duration.

Viagra tablets are blue and diamond-shaped, marked with the word "VIAGRA" marked on one side and the relevant strength marking on the other. This distinctive appearance is part of why the name has become so recognisable, but it is the sildenafil inside that does the work, not the shape or colour of the tablet.

Viagra vs Generic Sildenafil

Generic sildenafil is the generic form and generic drug version of branded Viagra. Both contain sildenafil as the active ingredient and must meet the relevant UK regulatory standards for quality, safety and effectiveness. The main differences are the brand name, packaging and generally the price, rather than the active ingredient itself.

Some people prefer the recognisable branded version. Others are happy with generic sildenafil once they understand it is not a lesser product. Your prescriber can talk you through both options during your consultation.

Who Regulates Viagra in the UK

The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating medicines in the UK. In Great Britain, legitimate online pharmacy supply should be through a pharmacy registered with the General Pharmaceutical Council (GPhC), with the appropriate clinical assessment where required.

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What Does Viagra Do?

Viagra works by improving blood flow to the penis during sexual arousal, which helps produce and maintain an erection firm enough for intimate activity. It does not create arousal on its own and only helps when you are sexually aroused.

How Viagra Works in the Body

The process behind an erection involves a chain of signals in the body, and Viagra works by supporting one specific step in that chain.

When physical stimulation causes arousal, your body releases nitric oxide in the penis. This triggers the production of another chemical called cGMP, which helps relax the smooth muscle and increase blood flow into the erectile tissue.

Normally, an enzyme called PDE5 breaks cGMP down fairly quickly, which is part of what brings an erection to an end. Sildenafil works by blocking PDE5. With less of the enzyme active, cGMP levels stay higher for longer, so blood flow is easier to achieve and sustain while arousal continues.

This is why Viagra is described as working "with" the body's natural arousal response rather than replacing it. Without that initial arousal signal, it cannot help you get an erection.

What Viagra Does Not Do

Because Viagra is so widely talked about, it is often credited with effects it does not actually have. A few of the most common misconceptions are worth clearing up directly.

• It does not increase desire, libido or interest in intimacy. It has no effect on those parts of the brain.
• It does not cause an erection without arousal, and physical stimulation is still required for it to work.
• It is not a permanent cure for erectile dysfunction. It is taken as needed to help manage erectile dysfunction, although the underlying cause may still need to be assessed.
• It does not increase the size of an erection beyond what the body can naturally achieve.
• It does not work instantly. It needs time to be absorbed before it takes effect.

How Long Does Viagra Take to Work?

On an empty stomach, Viagra can start working within around 30 to 60 minutes. Eating a large or high-fat meal can delay how quickly sildenafil takes effect.

Eating a large or high-fat meal before taking Viagra can delay this. A heavy meal can push the onset back by around an hour and reduce the peak amount of sildenafil reaching the bloodstream by roughly a third. If predictable timing matters to you, taking Viagra on an empty stomach or after a lighter meal tends to give more reliable results.

How Long Does Viagra Last?

Viagra's effects can last for up to around 4 hours, although this varies between individuals. This does not mean you will have a continuous erection, sexual stimulation is still required for an erection to occur.

Viagra Tablets: Strengths and How They are Taken

Available Strengths

Viagra tablets are available in three strengths: 25mg, 50mg and 100mg. Viagra's dosage depends on your response to treatment, age, general health, and any other medicines you take. For many men, 50mg is the usual starting dose,although a lower dose may be appropriate in some circumstances, including for certain men taking alpha-blockers. Your prescriber will determine the appropriate starting point for you as part of your assessment, and may adjust it based on how treatment goes. This is not something to work out for yourself.

How Viagra Tablets Are Taken

A Viagra tablet is swallowed whole with water and is generally taken approximately one hour before sexual activity. It can be taken with or without food, although a heavy or high-fat meal may delay its effect. It can be taken with or without food, though a heavy or fatty meal may delay how quickly it starts working. If you drink alcohol, it may be harder to get the best response, and alcohol can increase side effects such as headache and dizziness.

Viagra should not be taken more than once a day. If a dose does not seem to have worked, it should not be repeated on the same day. Speak to your prescriber if a particular strength is not giving the result you expected, rather than adjusting the dose yourself.

"Viagra Tablets" or "Viagra Pills"? Same Medicine, Different Words

People search for Viagra using several different terms, including "Viagra tablet" and "Viagra pills", and these all refer to the same product. In UK medical terminology, "tablet" is the standard term, since Viagra is a solid, compressed dose form rather than a soft capsule. "Pills" is simply everyday language for the same thing. Whichever word you use, the medicine, its strengths, and how it works are identical.

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Is Viagra Right for You?

Who Viagra Is Licensed For

Viagra is licensed for adult men experiencing erectile dysfunction, meaning a persistent or recurring difficulty achieving or maintaining an erection sufficient for satisfactory sexual performance. An occasional difficulty, particularly if it is linked to stress or tiredness, is common and does not necessarily mean treatment is needed. A proper assessment helps establish whether ongoing treatment is appropriate for your specific situation.

Who Should Not Take Viagra

Viagra is not suitable for everyone, and your prescriber will check for the following during your consultation:

• Anyone taking nitrate medications for chest pain, nicorandil, or riociguat. Combining these with Viagra can cause a dangerous drop in blood pressure.
• Anyone using recreational nitrates, sometimes known as "poppers", such as amyl nitrate.
• Men with certain cardiovascular conditions or who have recently experienced certain serious cardiovascular events, where sexual activity or treatment may be unsuitable.
• Men with certain severe heart conditions, including unstable angina or severe heart failure.
• Men with severe liver impairment.
• Men taking another PDE5 inhibitor medicine at the same time. These should never be combined.

This list is not exhaustive. Your prescriber will review your full medical history and current medicines during your consultation to see what may interact with Viagra, including whether certain prescription drugs or other prescription drugs raise the risk of drug interactions, whether low blood pressure, high blood pressure, or other medical conditions affect suitability, and whether certain medications can interact with sildenafil and cause significant side effects. Illegal drugs, including poppers, should not be combined with Viagra.

Possible Side Effects

Like all medicines, Viagra can cause side effects. The most commonly reported include headache, flushing, indigestion, nasal congestion, dizziness, and mild visual disturbances such as increased light sensitivity or a temporary blue tinge to vision. These are usually mild and pass on their own.

Rare but serious side effects need urgent medical attention. These include a sudden decrease or loss of vision or hearing, and an erection that continues for longer than 4 hours (priapism), which requires immediate medical assessment to avoid lasting damage. An allergic reaction is also possible, including a mild allergic reaction or, more rarely, a more severe allergic reaction. A severe allergic reaction is rare but possible and needs urgent medical attention. Men with certain blood conditions or anatomical deformities of the penis, including Peyronie's disease, may be at higher risk of priapism and should discuss this with their prescriber.

This is not a complete list of possible side effects. The patient information leaflet supplied with your medicine sets out the full picture, and you should read it before starting treatment.

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Getting Viagra in the UK

Prescription-Only Status Explained

Branded Viagra is classified as a prescription-only medicine (POM) in the UK, which means it can only be supplied following a prescription from a registered prescriber. Generic sildenafil at the same strengths is also POM.

There is one specific exception. Viagra Connect 50mg is classified as a Pharmacy medicine, meaning it can be supplied directly by a pharmacist following an appropriate consultation, without a prescription. It is an erectile dysfunction treatment, and studies report Viagra Connect is effective for 74% of men who use it. Every other strength and every other sildenafil-based product remains prescription-only.

How to Access Viagra Through EveryDayMeds

Genuine Viagra and generic sildenafil are available through EveryDayMeds via an online doctor consultation with UK-registered prescribers. You will complete a confidential medical questionnaire covering your health history, current medicines, and cardiovascular health. A prescriber reviews this before deciding whether treatment is appropriate for you.

If you are assessed as suitable, your prescription is dispensed by a GPhC-registered UK pharmacy and dispatched in discreet packaging. Pricing for branded Viagra and generic sildenafil is confirmed during your consultation and at checkout, so you know exactly what you will pay before completing an order.

Recognising a Genuine UK Pharmacy

Erectile dysfunction medicines are a common target for counterfeit and illegally supplied products, and the MHRA has reported that around 19.5 million doses of illegal erectile dysfunction medicines were seized in the UK between 2021 and 2025. Buying from an unverified source carries real risk, since there is no way to know what a counterfeit tablet actually contains.

A few signs can help you spot a pharmacy that is not operating properly:

• No consultation or medical questionnaire is required before you can buy
• Be cautious of websites that advertise prescription-only medicines in ways that do not comply with UK medicines advertising requirements, particularly where medicines are offered without an appropriate clinical assessment.
• The website looks poorly designed, uses persistent pop-ups, or has no verifiable pharmacy details.
• Payment is only accepted in cryptocurrency.
• there is no way to check the pharmacy's registration with the GPhC.

A genuine UK online pharmacy will always require a proper consultation before supplying a prescription-only medicine like Viagra, regardless of how quick or convenient the process feels.

Viagra at a Glance

Medical Disclaimer

This article is provided for general informational purposes only and does not constitute medical advice. It is not a substitute for a consultation with a qualified healthcare professional. Viagra and sildenafil are prescription-only medicines and should only be used under the supervision of an appropriately qualified prescriber, following an individual clinical assessment. Treatment suitability, dosage, and ongoing use should always be determined by your prescriber based on your personal medical history. If you experience an erection lasting longer than 4 hours, or any sudden change in vision or hearing, seek immediate medical attention. Results vary between individuals, and this content should not be used to self-diagnose or self-treat any condition.

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