Sildenafil: Uses, Side Effects, and Where to Buy in 2024

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Sildenafil treats erectile dysfunction (ED) and is the active ingredient in Viagra. In this article, we look at how sildenafil works for ED, other uses, and the best places to buy it online.
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This article discusses sildenafil, an ED drug, and how it works to relieve the condition.
A quick look at the best places to get sildenafil
Best overall: Roman Sildenafil | Skip to review
Roman Sildenafil
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Best range of ED medication: Hims Sildenafil | Skip to review
Hims Sildenafil
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Best for local pharmacy pick-up: Optum Perks Online Care | Skip to review
Optum Perks Online Care
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Most affordable: Lemonaid Sildenafil | Skip to review
Lemonaid Sildenafil
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What is sildenafil?
Sildenafil is the generic version of the brand-name drug Viagra and a popular treatment for ED. Those with this condition have difficulty getting or maintaining an erection. ED is a widespread condition, though many people find it difficult to discuss.
generic
widespread condition
The main ingredient in sildenafil is sildenafil citrate. The inactive ingredients include:
main ingredient
microcrystalline cellulose
anhydrous dibasic calcium phosphate
croscarmellose sodium
magnesium stearate
hypromellose
titanium dioxide
lactose
triacetin
artificial colors
Viagra is just one brand name drug containing sildenafil. This and other brand-name drugs containing sildenafil as an active ingredient will typically have inactive ingredients that differ, making them unique to that brand.
Viagra
Another brand-name medication containing sildenafil is Revatio, which also treats a condition called pulmonary hypertension.
Revatio
treats
pulmonary hypertension
A person cannot get sildenafil without a valid prescription from a doctor or prescribing healthcare professional in the United States.
Sildenafil dosage
Sildenafil comes in tablet form and is available in strengths of 25, 50, and 100 milligrams (mg). It also comes in 20-mg doses as the generic form of Revatio, but it does not have Food and Drug Administration (FDA) approval for treating ED.
How to use sildenafil
People generally take a 50-mg sildenafil tablet approximately 1 hour before sex. Regardless of the dose, a person needs to take sildenafil exactly as a doctor recommends and not more than once daily.
1 hour
Sildenafil is fast-acting, and its effects typically last up to 4 hours. However, the drug does not instantaneously produce an erection, and sexual arousal is necessary for the drug to work. Sildenafil also does not affect a person’s sex drive or libido.
sex drive
libido
Sildenafil may take longer to work if a person takes it with food. It is best to take the drug on an empty stomach. People can swallow sildenafil tablets with water.
take longer
How sildenafil works
Sildenafil belongs to a class of medications called phosphodiesterase type 5 (PDE5) inhibitors. These inhibit phosphodiesterase enzymes, which degrade the molecules that relax the muscle tissue. This allows for more relaxed penile muscles and increased blood flow, causing an erection.
phosphodiesterase type 5 (PDE5) inhibitors
enzymes
Though sildenafil does not cure ED, it can help treat the symptoms of the condition.
People are more likely to experience adverse reactions to the drug if they take more than the recommended amount.
more likely
Who should take sildenafil?
A person with symptoms of ED can try taking sildenafil if they first discuss it with a healthcare professional to ensure it is suitable. If appropriate, a doctor will provide a prescription.
The United Kingdom’s National Health Service (NHS) states that most males over the age of 18 can take sildenafil for ED.
National Health Service (NHS)
ED may sometimes signify an underlying health issue, so sildenafil may help treat some symptoms in individuals with certain conditions.
may sometimes
Some people with the following conditions may take sildenafil for treating ED:
type 2 diabetes
type 2 diabetes
multiple sclerosis
multiple sclerosis
heart disease
heart disease
high blood pressure
high blood pressure
atherosclerosis, which refers to the hardening of the arteries
atherosclerosis
arteries
Learn more about the causes of ED.
the causes of ED
People with pulmonary arterial hypertension can also take sildenafil to treat their symptoms. Sildenafil widens blood vessels and relaxes muscles, reducing blood pressure and improving circulation.
pulmonary arterial hypertension
According to the NHS, most children over 1 year and adults can take sildenafil for this pulmonary hypertension. The FDA recommends adults take 20 mg of sildenafil three times daily for this condition, with a 4- to 6-hour gap between doses.
NHS
FDA
A person always needs to seek a doctor’s guidance and recommendations when taking sildenafil for pulmonary hypertension.
Learn more about the use of sildenafil for pulmonary hypertension.
sildenafil for pulmonary hypertension.
Who should not take sildenafil?
People cannot take sildenafil if they already take nitrate medication that lowers their blood pressure. This is because sildenafil can further lower blood pressure and cause serious side effects, such as life threatening hypotension. Nitrate medications include nitroglycerin, isosorbide mononitrate, and isosorbide dinitrate.
cannot take sildenafil
blood pressure
lower blood pressure
hypotension
nitroglycerin
A person cannot take sildenafil if they have hypersensitivity to any ingredient in the drug. Other people who cannot take sildenafil include those with:
Pulmonary veno-occlusion: This involves the blockage of oxygen-carrying blood vessels from the lungs to the heart due to fiber buildup in small veins.
Left ventricular outflow obstruction: This refers to a heart condition that stops blood flow from the left heart ventricle.
Pulmonary arterial hypertension with sickle cell anemia: This refers to high blood pressure in the lungs with irregularly shaped red blood cells.
high blood pressure in the lungs
red blood cells
Multiple system atrophy: This is a rare condition that causes damage to the nerve cells in the brain over time.
Sildenafil drug interactions
Sildenafil can negatively interact with some medications, hindering their effectiveness or causing side effects.
Some types of medication a person should not take alongside sildenafil include:
Nitrates: Combing nitrates and sildenafil can cause very low blood pressure levels. This includes street drugs containing nitrates known as poppers.
poppers
Blood pressure medications: Taking blood pressure medications and sildenafil together can significantly reduce blood pressure levels.
Other PDE5 inhibitors: Taking sildenafil with another PDE5 inhibitor can increase the risk of side effects.
If a person is taking or plans to take any other medications, they must speak with a doctor before taking sildenafil. They should also mention to a doctor any vitamins, supplements, or herbal products that they take or plan to take before taking this medication.
vitamins
supplements
Sildenafil side effects
Below, we highlight the full range of side effects of sildenafil, from common to serious side effects that will need immediate medical attention.
Some common side effects of sildenafil include:
include
headaches
headaches
flushing
flushing
indigestion (dyspepsia)
dyspepsia
vision changes
nausea
nausea
dizziness
dizziness
rashes
rashes
nasal congestion
nasal congestion
back pain
back pain
Serious side effects of sildenafil include:
include
sudden and severe vision loss
vision loss
blurry vision
blurry vision
loss of hearing
loss of hearing
ringing in the ears (tinnitus)
tinnitus
dizziness
fainting
fainting
chest pain
chest pain
shortness of breath that worsens
shortness of breath
an erection that is painful and lasts longer than 4 hours (priapism)
priapism
symptoms of an allergic reaction, such as: a rashhivesitchingswelling of the eyes, mouth, lips, tongue, or throat
allergic reaction
a rash
hives
hives
itching
itching
swelling of the eyes, mouth, lips, tongue, or throat
swelling
lips
Anyone using sildenafil who experiences these side effects should seek immediate medical attention.
Consuming fruit juices such as grapefruit, pomegranate, Seville orange, and pomelo may interact with sildenafil and other PDE5 inhibitors. For example, grapefruit juice and grapefruits can increase the levels of sildenafil in the body, potentially leading to toxicity.
interact with sildenafil
increase the levels
Combining sildenafil with alcohol can also cause interactions. A 2019 study found that people who take sildenafil and other PDE5 inhibitors alongside alcohol can lead to side effects, including:
2019 study
indigestion
skin rash
headaches
facial flushing
chest discomfort and palpitations
palpitations
dizziness
altered vision
nasal congestion
Sildenafil overdose
If a person has taken too much sildenafil and has difficulty breathing, is unconscious, or has a seizure, they or someone near them should call emergency services at 911 immediately.
seizure
Otherwise, a person can call America’s Poison Centers for emergency attention at 1-800-222-1222 or visit the Poison Help website.
America’s Poison Centers
Poison Help website
A sign of a sildenafil overdose is an increase in the severity and duration of common side effects. Another indicator of a sildenafil overdose is vision changes, including impaired blue and green color distinction and blurred vision.
including
There are no antidotes available for a sildenafil overdose. If a person takes an overdose of this drug, they need to seek immediate medical attention or call poison control.
are no
Where to buy sildenafil online
People can use telehealth companies to buy sildenafil online. They often need to answer health questions and have an online appointment with a doctor before they can get a prescription. Below, we look at the best places to buy sildenafil online.
telehealth
buy sildenafil online
A person should ensure they carry out detailed research before purchasing ED medications online, as they are among the drugs most often counterfeited in the United States. They may have dangerous unlisted ingredients or quantities of ingredients or may not contain any of the ingredients it lists.
drugs most often counterfeited
Roman Sildenafil

Type: tablet
Accepts insurance: no
Dosage: 25 mg, 50 mg, 100 mg
Price per dose: $4 to $10
$4.00 AT RO
*Price may vary.

Roman, now called Ro, offers online support for people with ED and other health conditions. It has a team of qualified healthcare professionals who review a person’s medical information. The company also has a licensed pharmacy offering both generic and brand-name drugs.

It offers a range of sildenafil strengths at varying prices per dose:
25 mg: $4
50 mg: $6
100 mg: $10
Viagra costs $90 per dose.

First, a person attends an online health visit that focuses on their symptoms and medical history. If the doctor deems the treatment appropriate, the person will receive their prescription within 24 hours. The company offers free, 2-day shipping, which may be more convenient for some people than visiting a pharmacy.

It also offers free follow-up consultations to ensure the medication still works as doctors intended.
Insurance

Insurance companies do not typically cover Roman’s services, products, and medications. However, a person with insurance can check their plan to see whether they may claim reimbursement.

Learn more about Ro.
Learn more about Ro.

It offers a range of sildenafil strengths at varying prices per dose:
25 mg: $4
50 mg: $6
100 mg: $10
Viagra costs $90 per dose.

It also offers free follow-up consultations to ensure the medication still works as doctors intended.
Insurance

Insurance companies do not typically cover Roman’s services, products, and medications. However, a person with insurance can check their plan to see whether they may claim reimbursement.

Learn more about Ro.
Learn more about Ro.

offers a free online consultation
provides free and discreet shipping
free follow-up consultations
higher doses are more expensive
Viagra is much more expensive than sildenafil
only available to those with an internet connection
offers a free online consultation
provides free and discreet shipping
free follow-up consultations
higher doses are more expensive
Viagra is much more expensive than sildenafil
only available to those with an internet connection
Delivery time: 2 business days
Returns: no returns on prescription medication
Shipping: free shipping
Delivery time: 2 business days
Returns: no returns on prescription medication
Shipping: free shipping
Hims Sildenafil

Type: tablet
Accepts insurance: no
Dosage: 25 mg, 50 mg, 100 mg
Price per dose: $4 to $10
$4.00 AT HIMS
*Price may vary.

Hims offers a range of ED medications and puts people in contact with licensed healthcare professionals who ensure they receive tailored treatment.
Individuals can order sildenafil and Viagra from Hims, alongside alternatives such as Cialis, tadalafil, and vardenafil.
Cialis
vardenafil
Sildenafil prices vary by strength through Hims, such as:
25 mg: from $4 per tablet
50 mg: from $6 per tablet
100 mg: from $10 per tablet
Viagra costs around $139 per dose or $555 for 4 tablets.

The company offers ongoing care from its medical team at no additional cost.

Insurance plans will not cover Hims products, but the company states that its products are accessible to consumers and prices them 50% to 80% below retail cost.
50% to 80%

Learn more about Hims.
Learn more about Hims.

The company offers ongoing care from its medical team at no additional cost.

Insurance plans will not cover Hims products, but the company states that its products are accessible to consumers and prices them 50% to 80% below retail cost.
50% to 80%

Learn more about Hims.
Learn more about Hims.

lower cost per dose than other companies
ongoing care does not cost extra
wide range of alternative medication available
Viagra costs over $139 per dose
prices for some ED medication are unclear
lower cost per dose than other companies
ongoing care does not cost extra
wide range of alternative medication available
Viagra costs over $139 per dose
prices for some ED medication are unclear
Delivery time: 2 to 5 business days
Returns: no returns or refunds
Shipping: free shipping
Delivery time: 2 to 5 business days
Returns: no returns or refunds
Shipping: free shipping
Optum Perks Online Care

Accepts insurance: no
Virtual consultation fee: $25
Options offered: sexual health, skincare, general health, medication refills
Cost of medication included: no
GET STARTED WITH OPTUM
Optum Perks Online Care provides prescriptions, which it then sends to a person’s chosen pharmacy.
To use this service, a person needs to complete an online intake form. This form asks people for a medical history and what condition they need medication for. A healthcare professional will then review the form and prescribe medication if necessary. This process costs $25.
As Optum Perks does not dispense the medication directly, it cannot offer any sildenafil pricing information. However, people can use the service to find coupons or use their Optum Perks Discount Card to reduce the cost of medication at participating pharmacies.
Insurance
Optum Perks does not accept insurance, which means people need to pay the $25 consultation fee out of pocket.
As Optum Perks does not dispense the medication, individuals will need to choose a pharmacy that accepts their insurance plan.
Optum Perks Online Care provides prescriptions, which it then sends to a person’s chosen pharmacy.
To use this service, a person needs to complete an online intake form. This form asks people for a medical history and what condition they need medication for. A healthcare professional will then review the form and prescribe medication if necessary. This process costs $25.
As Optum Perks does not dispense the medication directly, it cannot offer any sildenafil pricing information. However, people can use the service to find coupons or use their Optum Perks Discount Card to reduce the cost of medication at participating pharmacies.
Insurance
Optum Perks does not accept insurance, which means people need to pay the $25 consultation fee out of pocket.
As Optum Perks does not dispense the medication, individuals will need to choose a pharmacy that accepts their insurance plan.
may be faster and cheaper to get prescriptions than a doctor’s office
people can choose which pharmacy they wish to use
coupons and discount cards can help reduce medication costs
insurance does not cover the consultation cost
medication costs are unknown unless people contact their local pharmacy
Optum Perks does not state which medication it can prescribe
may be faster and cheaper to get prescriptions than a doctor’s office
people can choose which pharmacy they wish to use
coupons and discount cards can help reduce medication costs
insurance does not cover the consultation cost
medication costs are unknown unless people contact their local pharmacy
Optum Perks does not state which medication it can prescribe
Shipping: pick-up from local pharmacy
Shipping: pick-up from local pharmacy
Lemonaid Sildenafil

Type: tablet
Accepts insurance: no
Dosage: 20 mg
Price per dose: $2
$2.00 AT LEMONAID
*Price may vary.
Lemonaid is a telehealth company that offers treatments and services for a range of health concerns, including mental health, men’s health, women’s health, and at-home testing.
The company offers sildenafil, as well as Viagra, Cialis, and tadalafil, to treat erectile dysfunction.
Lemonaid offers an affordable low dose of sildenafil for $2 per 20 mg dose. It must be noted that the 20mg dose of sildenafil has only been approved by the FDA to treat hypertension. A person taking it to treat ED will therefore be taking it off-label.
Lemonaid is a telehealth company that offers treatments and services for a range of health concerns, including mental health, men’s health, women’s health, and at-home testing.
The company offers sildenafil, as well as Viagra, Cialis, and tadalafil, to treat erectile dysfunction.
Lemonaid offers an affordable low dose of sildenafil for $2 per 20 mg dose. It must be noted that the 20mg dose of sildenafil has only been approved by the FDA to treat hypertension. A person taking it to treat ED will therefore be taking it off-label.
an affordable option at $2 per dose
company offers a wide range of health services
medication is delivered to a person’s door
20 mg sildenafil is not FDA-approved for ED
consultations are not free
an affordable option at $2 per dose
company offers a wide range of health services
medication is delivered to a person’s door
20 mg sildenafil is not FDA-approved for ED
consultations are not free
Delivery time: 2 to 3 business days
Prescription needed: yes
Location availability: available in the United States
Condition Tag: ED
Usage: take as needed
Effectiveness: lasts 2 to 5 hours
Returns: no returns on prescription medication
Shipping: free shipping
Delivery time: 2 to 3 business days
Prescription needed: yes
Location availability: available in the United States
Condition Tag: ED
Usage: take as needed
Effectiveness: lasts 2 to 5 hours
Returns: no returns on prescription medication
Shipping: free shipping
Comparison
The table below compares the telehealth companies offering sildenafil and Viagra.
Roman
Hims
Optum
Lemonaid
How we chose the best places to buy sildenafil
We selected these telehealth services based on criteria we think are good indicators of safety, quality, and transparency.
As a part of our vetting process, we consider:
a product’s composition, ingredients, and overall quality
any third-party certifications
a company’s reputation and business practices
any lab test results
marketing claims
Read more about how we vet products and brands.
how we vet products and brands
Frequently asked questions about sildenafil
Yes, sildenafil is as strong as Viagra. They both contain the same active ingredient.
Yes, sildenafil is as strong as Viagra. They both contain the same active ingredient.
Sildenafil can work for up to 4 hours. However, it does not stop an erection from going down after ejaculation. A study from 2005 suggested that sildenafil can reduce the amount of time a person waits to develop another erection after ejaculation, but more recent studies have not confirmed this.
can reduce
Sildenafil can work for up to 4 hours. However, it does not stop an erection from going down after ejaculation. A study from 2005 suggested that sildenafil can reduce the amount of time a person waits to develop another erection after ejaculation, but more recent studies have not confirmed this.
can reduce
Sildenafil is a PDE5 inhibitor that increases blood flow to the penis to help someone develop an erection. It does not cure erectile dysfunction it can help a person manage the condition.
Sildenafil is a PDE5 inhibitor that increases blood flow to the penis to help someone develop an erection. It does not cure erectile dysfunction it can help a person manage the condition.
People need to avoid using sildenafil if they are also taking nitrate medications. This is because both of these medications lower blood pressure. Taking sildenafil and nitrate medications together can make blood pressure dangerously low.
People need to avoid using sildenafil if they are also taking nitrate medications. This is because both of these medications lower blood pressure. Taking sildenafil and nitrate medications together can make blood pressure dangerously low.
Sildenafil takes up to 1 hour to work.
1 hour
Sildenafil takes up to 1 hour to work.
1 hour
Summary
Sildenafil is the generic version of the brand name drug Viagra. It is an effective erectile dysfunction (ED) drug available at a fraction of the cost of Viagra.
Sildenafil is just as safe and effective as Viagra. However, as with Viagra, it carries the risk of potential side effects and drug interactions.
People who experience ED need to discuss their treatment options with a doctor before taking any medications.

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