How long does sildenafil last for and how long does it take to work?

Imagine you’ve just popped your blue pill from its blister pack, excited about an evening of romance. You quickly glance at the remaining tablets and see that there’s only one left. Now you wonder: How long will this dose of sildenafil keep working, and will it be enough for your plans over the next few days? If only you had more tablets—and a blog like this—to guide you before your weekend getaway.

When it comes to treating erectile dysfunction, timing is everything. Sildenafil is a fast-acting, one-off treatment that doesn’t need to build up in your system. Just one tablet can do the job when taken at the right moment. So, how long does it take for sildenafil to kick in, and how long do its effects last? Let’s break down everything you need to know.

In this article, we cover all aspects of timing—from how quickly sildenafil enters your system to how long its benefits last. In addition to exploring the science of pharmacokinetics (don’t worry—we’ll explain that term soon), we will also review some basics about erectile dysfunction (ED) and sildenafil.

If you’re already familiar with some of these topics, you can use the handy navigation table below to jump to the sections that interest you most.

Main points

• Take sildenafil on an empty stomach: Sildenafil usually starts working within 30 minutes and reaches full effect within an hour on an empty stomach.
• Meal delay: If you’ve eaten recently, it might take about an extra hour for the pill to hit its peak effect.
• Duration of action: Once active, sildenafil typically remains effective for 4–6 hours at full strength.

How long does sildenafil last?

Sildenafil generally provides full potency for about 4 to 6 hours [1]. Although some effect might linger as long as the drug remains in your bloodstream, its strongest benefits are experienced during this window.

The half-life of sildenafil is the time it takes for the concentration to reduce by 50% in the blood and is about 3 to 4 hours. This means that the sildenafil  concentration in your blood drops by about 50% every 3 to 4 hours. So, it is mostly cleared from your system within a day [2].

The exact duration depends on individual factors like your body size, overall health, age, and the dose you took.

Remember, sildenafil (like other ED medications) won’t keep you erect for the entire period it’s in your system. It simply makes it easier to achieve a satisfactory erection when you’re sexually stimulated. Once the sexual arousal fades or after ejaculation, your erection will subside naturally.

How long does sildenafil take to work?

When taken on an empty stomach, sildenafil typically becomes effective within 30 minutes and reaches its maximum effect within an hour [3].

If you take it after eating, particularly after a heavy or high-fat meal, the absorption process may be slower. Sometimes taking an additional hour to reach peak effectiveness.

Your body’s size and weight also play a role; larger individuals might experience a slight delay in the drug’s action compared to those of average build.

Understanding erectile dysfunction

Erectile dysfunction (ED) is when a man finds it difficult to get or maintain an erection firm enough for satisfying sexual activity [4].

An occasional difficulty is normal, everyone has an “off day”. However, erectile dysfunction which lasts for more than six months, can impact your overall health and well-being.

Research predicts that around 322 million men worldwide could experience ED in the future [5].

Erectile dysfunction and heart disease

Chronic erectile dysfunction is often linked to other health issues such as heart disease, high cholesterol, high blood pressure [6].

Moreover, cardiovascular problems like clogged arteries and high blood pressure can limit blood flow to the penis. This makes it harder to achieve an erection[7].

In this way, chronic ED can act as an early warning sign for more serious cardiovascular issues. Researchers believe there is a window of about three years from the onset of erectile dysfunction to the development of major heart complications [8].

Diabetes and erectile dysfunction

In diabetes, consistently high blood sugar can damage blood vessels, a condition known as endothelial dysfunction. The high blood sugar also creates harmful byproducts, increase cellular stress, and damage nerves, all of which contribute to erectile dysfunction [9].

Diabetes can lead to two types of nerve damage: peripheral, which disrupts signals between the brain and the penis, and autonomic, which affects the muscles that control blood flow in the penis [10].

Low testosterone and erectile dysfunction

Low testosterone levels can also play a role in ED [11]. Often one of the first signs of low testosterone is a reduction in morning erections [12].

So, if you experience frequent erectile dysfunction, it might be time to have your hormone levels checked.

What is sildenafil?

Sildenafil is the generic form of the well-known blue pill, Viagra. It comes in three strengths:

• Sildenafil 25mg
• Sildenafil 50mg
• Sildenafil 100mg

For most men, a sildenafil 50mg dose is the typical starting point, which can be adjusted to sildenafil 25mg or sildenafil 100mg depending on your response and any side effects [13].

Sildenafil belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. Other drugs in this class include Cialis (Tadalafil), Spedra (Avanafil), and Levitra (Vardenafil).

These medications work by relaxing the blood vessels in the penis. This increases blood flow and helps you achieve an erection when sexually stimulated.

How do the different dosages of sildenafil compare?

The strength of sildenafil you take will affect both how long it lasts and how quickly it works. A larger dose may extend the duration slightly, but there’s a maximum limit of sildenafil100mg because higher doses can increase the risk of heart problems and more frequent side effects [13].

It’s important not to start on a high dose. Your body weight also influences effectiveness—for example, if you take a sildenafil 25mg tablet and are overweight, it might only work effectively for 2–3 hours.

Most healthcare professionals recommend starting with sildenafil 50mg dose and then adjusting it based on your individual needs.

How does sildenafil work?

Sildenafil boosts blood flow to the penis by blocking the enzyme PDE5, which normally breaks down a chemical called cGMP. Since the cGMP is not being broken down, it’s levels then rise [14]. Think of cGMP as the key that opens the “floodgates” for blood to enter the penis.

By keeping cGMP levels high, sildenafil helps relax the blood vessels, making it easier for you to achieve an erection when you’re aroused. However, it doesn’t create a continuous erection; it simply facilitates one when the conditions are right [15].

What is pharmacokinetics?

Pharmacokinetics is the study of how your body handles a drug—from the moment you take it until it leaves your system. The term comes from the Greek words “pharmakon” (drug) and “kinetikos” (movement) [16]. It covers four main processes, often remembered by the acronym ADME [16]:

1. Absorption: How the drug enters your bloodstream.
2. Distribution: How it spreads throughout your body.
3. Metabolism: How it is broken down, mainly by the liver.
4. Excretion: How it is eliminated from your body, usually in urine.

Understanding these processes helps explain why only about 41% of the active ingredient in an oral sildenafil tablet makes it into your bloodstream after liver metabolism [17].

When to take sildenafil

Timing your sildenafil dose is key to its success. To ensure it works exactly when you need it, consider:

• How long it takes to work: About 30 minutes on an empty stomach; possibly longer if you’ve eaten.
• How long it lasts: Approximately 4 to 6 hours of full effect, with diminishing benefits afterwards.

Sildenafil is a “one-and-done” medication, meaning you only take it when required. Once you take a single dose, it is quickly absorbed and reaches its peak concentration in about an hour.

Being one of the faster acting PDE5 inhibitors,  it’s absorbed quickly, reaching its peak in the bloodstream within about an hour.

The concentration of sildenafil in your blood tends matches the dose you took, however eating a meal when you take it may delay the absorption slightly. Despite the absorption being slowed down it doesn’t affect how much of the drug your body absorbs

Even though its effects may linger for a few hours, it won’t keep you continuously erect—the medication simply makes it easier to get an erection when you’re sexually stimulated.

How long does sildenafil remain in the body?

Sildenafil is cleared from your system fairly quickly. Its concentration typically drops by 50% every 3 to 4 hours, meaning it is mostly out of your body within a day.

Some men report that they can still feel mild effects up to 24 hours later [18], but full potency is generally observed for 4–6 hours [1].

Coupled with the fact that sildenafil is well tolerated within the typical dosage range (sildenafil 25mg to sildenafil 100mg) and it’s fast onset, makes it ideal for on-demand use in erectile dysfunction[19].

How long does sildenafil last for?

Sildenafil usually remains at peak effectiveness for about 4–6 hours  [1]. After this period, its benefits gradually decrease, although some mild effects might continue as long as the drug is present in your bloodstream.

The total duration can differ based on factors such as:

• overall health,
• age,
• dosage, and
• level of sexual activity.

Keep in mind that sildenafil, like other erectile dysfunction medications, does not provide a constant erection for its entire duration in your system. Instead, it simply helps you achieve an erection when you are sexually stimulated, and once the stimulation ends or after ejaculation, the erection will naturally diminish.

Does anything affect the longevity of sildenafil?

Like many medications, several factors can influence how long sildenafil remains effective. From dietary choices to other medications you take, understanding these elements can help you get the most out of your treatment.

• Alcohol: Consuming large amounts of alcohol may worsen erectile dysfunction, even when using sildenafil. Drinking heavily before your dose can make it harder to achieve and maintain a firm erection.
• Grapefruit Juice: Grapefruit juice can change the way sildenafil is absorbed in your body, making its effects less predictable. Some studies have shown that grapefruit juice may increase sildenafil levels, which could raise the risk of side effects [20].
• Age: Your age plays a key role in sildenafil’s effectiveness. Research indicates that while 80% of men under 65 see improvements with the medication, only 59% of men aged 75 and over experience stronger erections [21].
• St John’s Wort: Commonly used for ADHD, obsessive-compulsive disorder, and depression, St John’s Wort can interfere with sildenafil, reducing its effectiveness [22]. You might need a dosage adjustment or an alternative treatment if you’re taking this supplement.
• Cannabis and Cannabidiol (CBD): Sildenafil may interact with cannabis and CBD products. Using them together could increase the levels of sildenafil in your system, potentially leading to more serious side effects [23].

These factors can significantly affect how long sildenafil works for you, so it’s important to be aware of them when planning your treatment.

Can you make sildenafil last longer?

When you plan to use sildenafil, knowing how long its effects last is as important as knowing when to take it. Many users wonder if they can extend its benefits. While you can’t actually make the drug stay in your system longer than it naturally does, you can help optimise its effectiveness. Here’s how:

• Follow the prescription: Always take sildenafil exactly as your prescriber advises. This helps ensure the medication works both safely and effectively.

• Avoid alcohol: Drinking alcohol can interfere with achieving an erection even when using sildenafil. It’s best to steer clear of alcohol around the time you take your dose.

• Watch your diet: Eating fatty foods, like fatty meats, can slow down the absorption of sildenafil [17]. This delay might cause you to miss the window of optimal effectiveness. So, try to avoid high-fat meals when you take the medication.

How soon does sildenafil start working?

After you take a sildenafil tablet, you may wonder how quickly it helps you get an erection. The good news is that sildenafil is one of the fastest drugs in its group. It is absorbed quickly, reaching its highest level in your blood in about an hour, causing an erection within 60 minutes.

Studies show that, on average, the drug starts working in about 27 minutes. Some men even get an erection in as little as 12 minutes, but most (around 71%) experience an erection within 30 minutes [1].

Why does it take about 30 minutes to get an erection with sildenafil?

Even though one man was reported to achieve an erection in just 12 minutes after taking Viagra  [1], most studies show that it usually takes between 30 minutes and 3 hours [24].

There is a delay because the tablet has to pass through your stomach, be absorbed in your small intestine, and then go through your liver before it enters your bloodstream and reaches your penis.

It can take up to an hour for the effects to start, and only about 41% of the original dose actually gets into your circulation  [17]. This is why the tablets are made with higher doses, as not all of the active ingredient is absorbed.

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These patches are designed to be absorbed directly through the inside of your mouth (the buccal mucosa), which has a rich blood supply. This route bypasses the slow journey through your stomach, small intestine, and liver, allowing the medication to enter your bloodstream much faster.

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These triple combination ED soluble oral patches are available in various strengths to suit your specific needs.

Benefits of buccal administration of sildenafil

Using the buccal route to take sildenafil offers several advantages [25]:

• Easy to use: It’s simple and straightforward to administer.
• Quick absorption: The medication is absorbed faster when delivered through the inside of the mouth.
• Bypasses the liver: This method avoids first-pass metabolism in the liver—only about 41% of sildenafil from a traditional oral tablet reaches your bloodstream  [17].
• Improved absorption: It sidesteps the lower absorption rates that can occur in the gastrointestinal tract.
• Rapid action: The drug works quickly, providing faster relief.

Sildenafil drug interactions

Sildenafil is processed in your liver by enzymes called cytochrome P-450. Certain medications—such as cimetidine, erythromycin, and ketoconazole—can slow down this process, causing sildenafil to remain in your body for a longer period. This prolonged presence might sometimes require a dosage adjustment.

While sildenafil is generally safe, extra caution is needed when it’s used with the antiviral drug ritonavir, which is commonly prescribed to manage HIV/AIDS. Since ritonavir uses the same metabolic pathways as sildenafil, it’s advised that you do not exceed a dose of sildenafil 25mg within a 48-hour period when these drugs are combined.

Another important interaction to be aware of involves nitrates, which are used to treat conditions like angina and high blood pressure. Combining nitrates with sildenafil can lead to a sudden and potentially dangerous drop in blood pressure [26].

By understanding these interactions, you can help ensure that your treatment with sildenafil remains both safe and effective.

Can I take sildenafil with food?

Sildenafil (Viagra) works best when taken on an empty stomach. Food can slow down its absorption and delay reaching peak levels in your bloodstream. A high-fat meal can extend the time it takes to reach peak concentration to over an hour, with an average reduction in peak levels by about 29%  [17].

Can I take sildenafil with alcohol?

Although alcohol is often seen as a social lubricant that goes hand in hand with sildenafil, its effect on the drug’s absorption is minimal—since anything that slows stomach emptying, like a fatty meal, can have an impact, alcohol itself doesn’t significantly alter absorption [19].

However, this does not mean mixing alcohol with sildenafil is advisable, as doing so may still increase the risk of other complications. For instance alcohol can increase both SHBG and oestradiol levels which could impact a man’s testosterone levels and contribute to erectile dysfunction [27].

How the different dosages of sildenafil compare

The dose of sildenafil you take directly affects how long and how effectively it works. Higher doses, such as sildenafil 100mg, are used as the maximum to balance effectiveness with safety because doses above this level can lead to more frequent heart-related side effects.

On the other hand, lower doses like sildenafil 25mg might only last for 2-3 hours, especially if you have a higher body weight or more severe erectile dysfunction.

Generally, most men start with a 50mg dose, which can be adjusted based on your personal response and any side effects experienced  [19].

Sildenafil vs. other erectile dysfunction medications

Research has evaluated the pharmacokinetics of three PDE5 inhibitors used in treating erectile dysfunction: sildenafil, vardenafil, and tadalafil. The table below summarises their main findings [28].

• Sildenafil: Typically lasts 4-6 hours.
• Vardenafil: Similar duration but may work faster.
• Tadalafil: Can support erections for up to 36 hours.

These comparisons help you understand how sildenafil stacks up against other options, depending on your needs—whether you’re looking for a quick, on-demand solution or a treatment with a longer-lasting effect.

Understanding how factors like food, alcohol, and dosage affect sildenafil’s performance can help you use it safely and effectively for managing erectile dysfunction.

Table for results of comparison of different PDE5 inhibitors for erectile dysfunction.

Comparing PDE5 inhibitors

Vardenafil’s speed advantage

Research shows that among the PDE5 inhibitors, vardenafil works the fastest. It typically helps achieve an erection in about 40 minutes, compared to up to one hour for sildenafil and two hours for tadalafil [28].

Tadalafil’s extended duration

When it comes to lasting power, tadalafil stands out. Its half-life is approximately 17.5 hours, making it the longest-lasting option, while sildenafil’s half-life is only about 3.7 hours [28].

Potency differences

Laboratory studies, vardenafil demonstrated the highest potency—between 9 and 25 times stronger than sildenafil and 13 to 48 times stronger than tadalafil [28].

Duration of ED medications

Oral erectile dysfunction treatments generally fall into two categories based on how long they last:

• Short-Acting (4-6 hours): This group includes sildenafil (Viagra), vardenafil (Levitra) [28], and avanafil (Spedra) [29]. They work quickly, making them ideal for planned encounters.
• Long-Acting (Up to 36 hours): Tadalafil (Cialis) offers support for up to 36 hours, which is perfect if you need a treatment that covers a longer period, like a spontaneous weekend away [28].

If you prefer a medication that gives you quick, reliable performance, sildenafil remains a top option. However, if you need longer-lasting support, tadalafil might be the better choice.

Summary on how long sildenafil lasts and how long it takes to work

• Sildenafil usually reaches its full effect about one hour after you take it.
• Taking it on an empty stomach often makes it kick in faster.
• Once it starts working, the medicine stays effective for roughly 2 to 6 hours, depending on the dose.
• It helps you get an erection when you’re sexually aroused. After sex your erection will go down as usual once you’re no longer excited.
• Its effects wear off over time and will be completely gone by the next day.
• Taking more than the recommended maximum dose won’t make it work any better and could cause side effects.
• Sildenafil is ideal if you only need support for erectile dysfunction once in a while, rather than taking a pill every day.

If you want to try sildenafil, complete an online consultation at Courier Pharmacy to get started.

Getting guidance for erectile dysfunction

Talking about erectile dysfunction shouldn’t be embarrassing – think of it as a warning sign that something might be off with your blood vessels, or perhaps even a sign of a psychological issue.

No matter the cause, the team at Courier Pharmacy is here to help. We provide expert advice on choosing the right treatment, guidance on what to do if PDE5 inhibitors aren’t working, and can even help design a completely personalised plan for you. The first step is to contact us with any questions you may have.

Why choose Courier Pharmacy for sexual health support?

If you’re considering sildenafil or exploring other options for treating erectile dysfunction, it’s vital that your treatment is right for you. Our comprehensive healthcare questionnaires ensure that the chosen option is safe. Should you need any additonal guidance our experts prescribers are always available for FREE consultations.

Here’s why Courier Pharmacy is the right choice for your sexual health support:

• Private, non-judgmental consultations from the comfort of your home
• Personalised recommendations based on your complete health profile
• Health screenings to confirm if sildenafil is the right treatment for you
• Ongoing support and follow-up throughout your treatment
• Clear advice on realistic treatment expectations
• Holistic guidance on lifestyle changes to support sexual health
• An approach based on the latest evidence-based medicine

With Courier Pharmacy, you’ll gain a practical understanding of what sildenafil can—and cannot—do for your erectile dysfunction and sexual health. This will help you set healthy expectations and make well-informed treatment decisions. For any questions or further assistance, please contact us.

Disclaimer: This article is for informational purposes only and does not replace professional medical advice.

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