Key takeaways
Sildenafil (the active ingredient in Viagra) is a prescription medication for erectile dysfunction (ED) that works in part by increasing blood flow to the penis, helping to achieve and maintain an erection during sexual activity.
The effects of sildenafil typically last around four to six hours, but a low (and probably inactive) level of the medication can stay in your system for up to 24 hours, depending on factors like metabolism, age, and health conditions.
While sildenafil is effective for many, its success depends on proper timing, arousal, and dosage. Your healthcare provider can help you find the safest and most effective dose for your needs.
Here's what we'll cover
Here's what we'll cover
Key takeaways
Sildenafil (the active ingredient in Viagra) is a prescription medication for erectile dysfunction (ED) that works in part by increasing blood flow to the penis, helping to achieve and maintain an erection during sexual activity.
The effects of sildenafil typically last around four to six hours, but a low (and probably inactive) level of the medication can stay in your system for up to 24 hours, depending on factors like metabolism, age, and health conditions.
While sildenafil is effective for many, its success depends on proper timing, arousal, and dosage. Your healthcare provider can help you find the safest and most effective dose for your needs.
Erectile dysfunction (ED) makes it difficult to get or maintain an erection firm enough for sex. Thankfully, medications like sildenafil—better known by its brand name, Viagra—have helped many regain confidence and improve their sexual health.
Sildenafil works by boosting blood flow to the penis, which can help you get more reliable erections when aroused. But like any medication, its effects have a timeline, and understanding how long sildenafil stays in your system can help you get the most out of your treatment.
Let’s explore what sildenafil does and how you can use it safely and effectively.
Viagra Important Safety Information: Read more about serious warnings and safety info.
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How long does sildenafil stay in your system?
Sildenafil can stay in your system for up to 24 hours, though its effects are strongest for about four hours after taking a dose. This timeframe is linked to sildenafil’s half-life—the amount of time it takes for half of a drug's active substance to be eliminated from the body—of approximately four hours.
It generally takes about 16 to 20 hours (or 4–5 half-lives) for sildenafil to be almost entirely eliminated from the system––sometimes referred to as the washout period for sildenafil.
Keep in mind that, while sildenafil is most effective for about four hours, that doesn’t mean you’ll have an erection that lasts four or more continuous hours (in fact, if that happens, you should seek medical advice from a healthcare professional immediately). When Viagra is active in your system, that just means you’re best equipped to get a strong erection with arousal and stimulation during that period.
How long does generic Viagra last?
Since generic Viagra contains the same active ingredient (sildenafil) as brand-name Viagra, it stays in your system for the same amount of time—up to 24 hours. Like the brand-name version, generic Viagra remains most effective for about four hours after you take it, during which time it can be easier to get and maintain an erection when sexually stimulated.
Sildenafil’s effectiveness decreases as the body processes and eliminates the medication. Multiple factors can affect how long it works for you, including:
Food intake: Consuming a high-fat meal before taking sildenafil can delay the drug's absorption, slowing its onset of action which could reduce its effectiveness. In studies, high-fat meals delayed peak plasma concentration by up to 60 minutes and reduced overall drug absorption by nearly 30%.
Metabolism and health conditions: Those with faster drug metabolisms may experience shorter drug effectiveness, while those with conditions such as liver or kidney impairment may retain sildenafil longer.
Age: People 65 years and older may metabolize medications more slowly due to age-related changes in liver and kidney function. Slower metabolism can prolong the presence of sildenafil in the bloodstream, potentially extending its effectiveness while also increasing the likelihood of side effects.
While a higher dose could give more noticeable results during the first four hours, especially if you aren’t getting the effects you want on lower doses, it won’t extend how long the medication works. And taking more medication than prescribed can cause unwanted side effects like headaches, facial flushing, or even a drop in blood pressure.
This is because your body processes the drug the same way, no matter the dose. That’s why healthcare providers recommend the lowest effective dose that fits your health needs and goals.
Factors that can affect how long sildenafil stays in your system
Several factors can influence how quickly sildenafil is processed and eliminated from your system, including interactions with other medications, specifically:
CYP3A4 inhibitors: Certain antifungal and antibiotic drugs, such as ketoconazole and itraconazole can block the enzyme that breaks down sildenafil. This leads to higher drug levels in your system and increases the risk of side effects, including dangerously low blood pressure.
Ritonavir and HIV medications: HIV medications like ritonavir can dramatically raise sildenafil levels—up to 11 times the normal concentration. For this reason, people taking these drugs are usually advised to use very small doses of sildenafil to minimize risks.
If you take other medications or have existing health conditions, consult your healthcare provider to ensure the safest and most effective treatment plan.
How long sildenafil lasts by dosage
Sildenafil is prescribed in different dosages for different purposes, though the amount of time it stays active in your system remains about the same, no matter the dose. Here’s an overview of the most common dosages you may encounter:
Dosage | Who it's for | How long it lasts | Special considerations |
|---|---|---|---|
20 mg (FDA approved for pulmonary arterial hypertension) | Traditionally used to treat pulmonary arterial hypertension, though it may be used off-label for ED | Similar absorption and duration as ED doses | Used under medical guidance for pulmonary hypertension. Since it has the same active ingredient, it may be prescribed off-label for ED for greater dosage flexibility. |
25 mg | Those sensitive to higher doses or taking interacting medications | 4–5 hours with milder effects | Lower side effect risk; often prescribed for older adults or those on multiple medications |
50 mg | Standard starting dose for most people with ED | 4–6 hours with peak effects around one hour after taking | As with all dosages, best taken on an empty stomach; high-fat meals may delay absorption |
100 mg | For those who need a stronger effect when 50 mg is not enough | 4–6 hours with stronger effects but same duration as lower doses | Extra guidance from healthcare provider needed due to higher side effect risks |
How long does 20 mg of Viagra stay in your system?
A 20 mg dose of sildenafil can stay in your system at a low level for up to 24 hours, though its effects typically last about four hours after taking it. This dosage follows the same process for elimination as higher doses used for ED.
While a 20 mg dose is not commonly prescribed for ED, it is approved by the US Food and Drug Association (FDA) under the brand name Revatio to treat pulmonary arterial hypertension (PAH), a lung disorder. It does have the same active ingredient as Viagra, so healthcare providers may recommend this lower dose off-label for ED if you are sensitive to higher doses of sildenafil or if you’re taking medications that interact with it. Sometimes, it’s also used for greater dose flexibility.
How long does 25 mg of Viagra stay in your system?
A 25 mg dose is often recommended for people who are sensitive to higher doses or who take other medications that might interact with sildenafil. While this dose produces a milder effect, it still works for about four to six hours. Fewer side effects occur than with higher doses because the body is exposed to a lower amount of the drug.
How long does a 50 mg sildenafil dose stay in your system?
A typical starting dose of sildenafil for erectile dysfunction is 50 mg, though this may vary depending on your age and other health conditions. After taking this dose, the drug usually remains effective for about four to six hours. Its effects are typically strongest around one hour after ingestion, when the drug reaches peak levels in the bloodstream, though this can be longer if you eat a high-fat meal around the same time as you take it.
However, how long sildenafil works can depend on how the body absorbs, breaks down, and clears the drug.
How long does a 100 mg sildenafil dose stay in your system?
For those who don’t experience the desired effects with 50 mg, healthcare providers may prescribe a 100 mg dose. While this higher dose provides a stronger response, it doesn’t change how long sildenafil remains in the body.
Like the 50 mg dose, its effects typically last four to six hours, though individual factors such as metabolism and drug interactions can impact this timeframe.
A 100 mg dose should only be taken with approval and guidance from a healthcare provider, as it increases the risk of side effects like headaches, dizziness, and facial flushing. ED medication also carries the potential of rare, but dangerous side effects you should know about. This includes priapism (an erection that lasts longer than four hours), which requires emergency medical attention.
Keep in mind that your healthcare provider tries to balance the benefits of ED medication with the risks. This is why they may start you on a lower dose before bumping you up to higher dosages if your body truly needs it. Keep in mind people with specific health conditions may also need lower doses to reduce risks specific to them.
Important medical interactions
Taking sildenafil safely isn’t just about the dosage numbers. It can interact with several types of medications, which may increase its concentration in your body and raise the risk of serious side effects like low blood pressure. These include:
Antifungals: Medications like ketoconazole and itraconazole can slow down how your body breaks down sildenafil, keeping the drug in your system longer.
HIV medications: Certain antiretroviral drugs like ritonavir can increase sildenafil levels by up to 11 times, requiring much lower doses.
Antibiotics: Erythromycin and other antibiotics can interfere with sildenafil’s breakdown, leading to higher drug concentrations.
Blood pressure medications and nitrates: These can cause a dangerous drop in blood pressure when combined with sildenafil.
Your healthcare provider may limit your sildenafil dosage to once every two or three days if you take any of these medications. This list is not exhaustive, so always tell your healthcare provider about all medications, supplements, or recreational drugs you use before starting sildenafil.
How to get the most out of sildenafil
ED can be a stressful experience, and if it’s your first time using sildenafil, you might not know exactly what to expect. It can take a few tries to figure out how your body responds so you can ensure the best experience. Here are some tips to help you get the best results.
1. Time your dose right
Taking sildenafil at the right time maximizes its effectiveness. The best time to take it is about 30 minutes before sexual activity, though it can be taken up to four hours in advance.
This timing allows the medication to reach peak concentration in the bloodstream, making it easier to achieve and maintain an erection when sexually stimulated.
You can always try the dose to check its effects on your body on a day you are not planning for partnered sexual activity to see how it works for you. Remember, the medication may make it easier to get and keep an erection but it won’t make an erection happen out of nowhere. Sexual stimulation is still required to get an erection.
2. Manage your expectations
It’s important to remember that sildenafil isn’t an “on-switch” for erections—it works with your body’s natural response to sexual stimulation. You’ll still need to be aroused for the medication to help you get and maintain an erection.
Stress, anxiety, or even relationship concerns can affect how confident you feel in the bedroom. Creating a relaxed, supportive environment can help you feel more comfortable about taking medication to help you get an erection.
3. Consider other lifestyle factors
Several lifestyle choices can influence how well sildenafil works.
For example, moderate drinking—one or two standard drinks weekly—is usually fine, but heavy drinking (more than eight drinks per week for women or 15 for men) can make it harder for Viagra to work effectively. Alcohol can also cause blood pressure to drop, leading to dizziness or lightheadedness.
4. Precisely follow your healthcare provider’s recommendations
Sildenafil is typically prescribed in doses of 25 mg, 50 mg, or 100 mg, depending on individual needs and how well you tolerate the medication.
Never take more than one dose within a 24-hour period. Exceeding the recommended dose increases the risk of side effects.
If sildenafil doesn’t seem effective the first time, don’t lose hope—it can take a few tries to understand how your body responds. If the problem persists, consult your healthcare provider. They may adjust your dosage or suggest alternative treatments tailored to your specific health needs.
How long can you take Viagra for?
Clinical trials involving thousands of men have consistently shown that Viagra is both safe and effective when used over long periods. In these studies, people continued to experience the benefits of Viagra with minimal side effects, even after years of use.
Is long-term Viagra use safe?
Yes, long-term use of Viagra is considered safe for most people. Like any FDA-approved medication, Viagra can come with some side effects. While most are mild and temporary, it’s important to understand what to expect and when to get help.
What are common side effects of sildenafil & Viagra?
Mild side effects of Viagra often go away within a few hours and include:
Headaches
Facial flushing
Indigestion or upset stomach
Stuffy nose
Changes in vision (e.g., sensitivity to light or altered color perception)
Since these effects can vary from one person to the next, it’s important to work with your healthcare provider to try different dosing options and figure out what works best for you.
Which side effects are rare?
Some less common side effects include:
Muscle pain or back pain
Low blood pressure or dizziness
Nausea
Rash
Since sildenafil can lower blood pressure, if you already have low blood pressure or take medication for high blood pressure, you should let your healthcare provider know before they prescribe Viagra to you.
In very rare cases, Viagra can cause:
Priapism: A painful erection that lasts longer than four hours. This is considered a medical emergency and requires emergency medical attention immediately.
Sudden vision or hearing loss: If you experience sudden changes in your ability to see or hear, it’s crucial to get medical help right away.
If you experience any of these rare side effects, seek emergency medical attention. Remember, if you have any concerns or questions, don’t hesitate to discuss them with your healthcare provider.
Why do some people stop taking Viagra?
According to a long-term study, discontinuing Viagra typically has more to do with personal circumstances than with the medication itself. In large-scale studies, fewer than 4% of participants discontinued use due to side effects over 4–5 years.
Some people stop taking Viagra because of changing health conditions, evolving personal relationships, or even financial considerations.
If you’re thinking about using Viagra over a long period, regular check-ins with your healthcare provider are crucial. They can adjust your dose if needed, monitor for any side effects, and ensure that the medication continues to work well for you.
Here are some tips to keep in mind:
Follow your prescription: Take the medication exactly as prescribed. Don’t increase your dose without talking to your provider.
Be aware of side effects: Pay attention to how your body responds. If you notice any unusual side effects, let your healthcare provider know.
Take care of your health: Managing conditions like high blood pressure, diabetes, or heart disease can help you continue to use the medication safely.
Communicate openly: Share any concerns with your healthcare provider so they can recommend adjustments or alternative treatments if necessary.
With proper use and regular medical supervision, Viagra can be a safe, effective, and lasting solution for managing ED, helping you maintain confidence and improve your quality of life.
Does sildenafil stay in your system longer than tadalafil?
Viagra (sildenafil) stays in your system for about four to six hours, with its effects gradually wearing off after the first few hours. In contrast, Cialis (tadalafil), another popular ED medication, can last up to 36 hours at levels effective enough for a physical response from your body, offering a much longer window for sexual activity.
When comparing Cialis and Viagra, or sildenafil and tadalafil, the key difference lies in how long they stay active in the body. While both medications belong to the same class of drugs (PDE5 inhibitors), their durations of action vary significantly.
Tadalafil is designed to be more long-lasting than sildenafil, earning it the nickname, “the weekend pill.” This extended window offers more flexibility, making tadalafil ideal for those who prefer not to plan sexual activity too precisely.
For added convenience, Cialis is also available in a low-dose daily option (2.5 mg or 5 mg), allowing users to maintain a steady level of the drug in their system. This means spontaneous sexual activity can become easier because the medication is always active in your system.
You can also take daily Cialis in a chewable gummy form, with Ro’s Daily Rise Gummies, which stay active in your system for over 24 hours. Another option is Ro Sparks, a dissolvable tablet that combines sildenafil and tadalafil; it takes effect within 15 minutes and stays active in your system for up to 36 hours.
Cialis Important Safety Information: Read more about serious warnings and safety info.
Which one is right for you?
Choosing between sildenafil and tadalafil depends on your preferences and lifestyle:
For immediate, short-term use: Sildenafil is a good option if you want a fast-acting medication that works within 30–60 minutes and lasts for a few hours.
For more flexibility: Tadalafil is ideal if you prefer a longer-lasting effect or want the convenience of a low-dose daily option.
Talk to your healthcare provider to find the medication that best fits your needs, taking into account your health history, lifestyle, and treatment goals.
Medication options for ED treatment
Ro offers several ED treatments, including generic sildenafil, brand-name Viagra, generic tadalafil, and brand-name Cialis.
You could also consider one of Ro’s unique formulations called Ro Sparks. These combine sildenafil and tadalafil into one dissolvable tablet for both fast and long-lasting effects, which can help you get and maintain erections when needed. Though this particular formulation is not FDA-approved, it is composed of active ingredients that have been FDA-approved for erectile dysfunction.
Along with that, there are daily medication options to consider:
Daily Rise Gummies contain 7 mg of tadalafil in a once-a-day gummy, helping you maintain the ability to get and keep an erection without timing your dose around sex.
Daily Cialis pills come in 2.5 mg and 5 mg doses for daily use.
Talk to your healthcare provider to find the right option for your sexual health needs.
Bottom line: how long does sildenafil stay in your system?
Knowing how long sildenafil stays in your system and what can influence its duration can help you get the best results while staying safe and informed about your treatment options.
Sildenafil (Viagra) is typically active for about four to six hours, but low levels of the drug can remain in your system for up to 24 hours. Factors like age, metabolism, and overall health play major roles in how long it stays active.
It comes in four primary doses: 20 mg (originally made for pulmonary hypertension), or 25 mg, 50 mg, or 100 mg for ED. Dose doesn’t significantly impact how long the drug lasts in your system.
If you’re looking for a longer-lasting option, tadalafil (Cialis) is another effective ED treatment that lasts up to 36 hours (or can be taken on a daily basis so you’re ready for sexual activity at any time).
Frequently asked questions (FAQs)
How long does Viagra take to work?
For most people, Viagra typically reaches its peak in your bloodstream at the 1-hour mark. If you’re taking it for the first time, the makers of Viagra recommend planning to take it about an hour before sexual activity.
That said, the exact timing for it to take effect can vary depending on factors like your metabolism, whether you’ve eaten a high-fat meal recently, and whether you’re aroused.
Here’s what the research has shown: A study found that some people were able to get an erection within 12 minutes of taking Viagra. Another trial found that the average time it takes for people to get an erection is around 27 minutes after taking the medication. Results may vary depending on factors that are unique to you, such as your age and other health conditions.
If you’re taking Viagra as prescribed and still not seeing the results you want, your healthcare provider can help adjust your dosage or recommend alternative treatments that might work better for you.
When should you take sildenafil (Viagra)?
The best time to take sildenafil is about 30 to 60 minutes before you plan to have sex, though the medication can be effective even sooner. It remains active for approximately four hours, which gives you a relatively flexible window for having sex.
When you’re taking sildenafil, keep in mind that your food choices, like taking it with a high-fat meal, can delay its effects by slowing the drug’s absorption into the bloodstream.
If you’ve already taken sildenafil, make sure you wait at least 24 hours before taking another dose. Doubling up on your medication won’t improve the results; instead, it could increase the risk of side effects.
Does sildenafil affect how long you last?
While sildenafil isn’t specifically FDA-approved to delay ejaculation, research shows that it can offer other benefits for sexual confidence and satisfaction.
For example, studies found that people taking sildenafil reported feeling more in control of when ejaculation happens. While it didn’t significantly increase the time before ejaculation, the improved sense of control helped reduce anxiety during sex.
Those using sildenafil also reported higher sexual satisfaction scores, likely because of stronger erections and an improved overall experience in the bedroom.
In addition to these benefits, some studies suggest that sildenafil could be helpful when combined with other treatments:
Combination with SSRIs: Studies show that pairing sildenafil with selective serotonin reuptake inhibitors (SSRIs) like fluoxetine can extend the time to ejaculation. The SSRI could potentially delay ejaculation by increasing serotonin levels which inhibits the ejaculatory reflex, while sildenafil improves erection quality in those who need it.
Performance anxiety reduction: By indirectly addressing performance anxiety, sildenafil may indirectly reduce premature ejaculation in men who experience premature ejaculation related to anxiety or psychological stress.
What sildenafil won’t do
To help set your expectations, it’s worth mentioning that erectile dysfunction pills such as sildenafil can only help you get an erection if you’re aroused. It won’t:
Affect the ejaculation process: Sildenafil doesn’t target the ejaculatory reflex, so it won’t prevent you from climaxing sooner than you’d like.
Improve your sex drive: Sildenafil only works when you’re already sexually aroused—it doesn’t increase desire or improve libido (though increased confidence in sexual activity could indirectly improve your interest in sex).
If premature ejaculation is your main concern, discuss your options with a healthcare provider, as there are other options like numbing wipes that may help you prolong your erections. If you struggle with both erectile dysfunction and PE, be sure to discuss sildenafil, as the medication could improve your sexual experience by helping you get and maintain an erection, which may reduce anxiety associated with sexual activity.
Talk to your healthcare provider to explore personalized treatment options and find the best approach for you.
How long does sildenafil show up on a drug test?
Sildenafil (Viagra) is not typically included in standard drug screenings, as these tests focus on detecting substances of abuse like opioids, amphetamines, or THC.
But if a test specifically targets sildenafil—for example, in a clinical study or forensic investigation—its detectability depends on how your body processes it and breaks it down.
After a standard dose of sildenafil, it takes about 24 hours to be almost completely eliminated from the body, though small traces may persist longer, depending on dosage, individual metabolism, and the sensitivity of the test used.
Advanced tests, such as high-performance liquid chromatography (HPLC) or mass spectrometry, can detect sildenafil in blood or urine for up to 24 to 48 hours after use. Its primary breakdown product also leaves the body quickly, making it harder to detect after the first day.
Unless someone specifically requests a test for sildenafil, its use is unlikely to be flagged in routine drug screenings.
DISCLAIMER
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
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