Sildenafil vs Tadalafil: Which ED Med Fits Your Life?

December 24, 2025
Blog
Journal

Authors

Reviewed by Dr. Rasoul Montazeri

Triple Board Certified Physician and The Founder

Niayesh Najafi

Medical student and researcher in Health Sciences

Table of contents

ED Medications: An Overview
Sildenafil (Viagra): Key Features
Tadalafil (Cialis): Key Features
ED Medication Comparison: Onset & Duration
Side Effect Profiles: What Patients Should Know
Have Questions? Healthon Is Here to Help
Frequently Asked Questions

Key takeaways

Sildenafil lasts 4-6 hours, ideal for planned use; Tadalafil lasts up to 36 hours, offering more spontaneity.
Sildenafil works in 30-60 minutes; Tadalafil takes 30-120 minutes to start working.
Both can cause headache, flushing, and indigestion; Tadalafil may cause muscle/back pain, while Sildenafil can cause visual changes (e.g., blue tint).
Sildenafil is best for occasional, planned use; Tadalafil is better for frequent or spontaneous activity.

Close-up of blue erectile dysfunction tablets representing sildenafil and tadalafil PDE5 inhibitor medications

Selecting between sildenafil and tadalafil depends on dosing preference, duration of effect, and how the medication fits into daily life. Sildenafil (Viagra®) is typically taken on demand and has a shorter duration of action, while tadalafil (Cialis®) has a longer half-life that allows for extended effectiveness and greater flexibility with timing.

Both medications are widely prescribed PDE5 inhibitors that improve erectile function through the same biological mechanism. However, differences in onset time, duration, food interactions, side-effect profiles, and cost can influence which option is the better fit. This guide compares sildenafil and tadalafil across these key factors to help patients and clinicians make informed, personalized treatment decisions.

ED Medications: An Overview

Illustration explaining how ED medications like sildenafil and tadalafil improve blood flow by inhibiting the PDE5 enzyme

Sildenafil and tadalafil are in a group of medicines called phosphodiesterase type 5 inhibitors. These drugs are used to treat sexual dysfunction for people. They help increase blood flow to the penis when there is sexual stimulation. This helps you get and keep an erection that is hard enough for sexual intercourse.

These medicines work by stopping the PDE5 enzyme, which usually breaks down something called cyclic guanosine monophosphate. When there is more cGMP in the blood vessels in your penis, the smooth muscle relaxes. This lets more blood flow in. You need to be sexually aroused for these phosphodiesterase inhibitors to work.

Next, we will look at the common side effects of sildenafil and tadalafil, and see what makes each one different.

Sildenafil (Viagra): Key Features

Sildenafil citrate, also called Viagra, is made for use when you need it. You should take it about 30 to 60 minutes before you plan to have sex. This time helps the medicine get into your body so it can work to improve blood flow when there is sexual stimulation.

The efficacy of sildenafil is known to be good. Still, food can change how your body takes it in. If you want the fastest onset of action, it's best to take it on an empty stomach. Eating a big, high-fat meal can slow down how fast it works. Most of the time, the effects last for about four to six hours.

Tadalafil (Cialis): Key Features

Tadalafil is sold under the brand name Cialis. People often call it "the weekend pill" for a good reason. It has the longest duration of action out of all PDE5 inhibitor medicines. Its effects can last up to 36 hours. This long-lasting effect gives you more freedom and spontaneity when it comes to sexual intercourse. You do not have to worry about taking the dose right before you want to have the sexual activity.

Tadalafil may also be taken as a low-dose daily pill, which maintains steady levels of the medication in the body. This approach supports continuous erectile readiness and removes the need to plan ahead for sexual activity.

ED Medication Comparison: Onset & Duration

When choosing an ED medication, the speed and length of its effects are major factors. Sildenafil often works a bit faster, especially without food, making it suitable for planned sexual activity. In contrast, tadalafil’s extended duration offers a level of spontaneity that many users prefer.

This difference is a key reason why your doctor might recommend one over the other. The choice depends on whether you prefer to plan your encounters or want the freedom to be spontaneous. Here is a direct comparison:

Feature	Sildenafil (Viagra)	Tadalafil (Cialis)
Onset of Action	30-60 minutes	30-120 minutes
Duration of Action	4-6 hours	Up to 36 hours

Side Effect Profiles: What Patients Should Know

Man holding stomach at home illustrating possible gastrointestinal side effects of erectile dysfunction medications

Both drugs have undergone clinical trials and are considered safe for most men. Still, they can cause side effects. Many of the most common side effects are similar, while others differ. Being aware of these potential effects helps support informed treatment decisions.

Knowing the possible side effects can help you and your doctor understand the risk factors. This can help you pick the best one. Below, we talk about the common side effects and some unique ones for each.

Common Side Effects of Sildenafil

The side effects of sildenafil citrate are usually not strong, and they go away quickly. Many men get these side effects when they start using the medicine, as the body gets used to it. If the effects of sildenafil last a long time or bother you, it may be a good idea to talk to your doctor. You and your doctor can look into changing your medicine to something else, like tadalafil.

The most common effects of sildenafil happen because of changes in blood flow in other parts of your body.

Common side effects of sildenafil include:

Headache
Facial flushing
Upset stomach or indigestion
Nasal congestion
Changes in vision, such as a blue tint (cyanopsia) or blurry sight

Common Side Effects of Tadalafil

Tadalafil has some of the same side effects as sildenafil. For example, people get headaches and also flushing. But what makes tadalafil different is that it often causes muscle pain. This muscle pain is not seen often with sildenafil.

Most of the side effects of tadalafil are mild. Many times, they go away on their own. Since the medication has a long duration of action, the side effects can last longer, too.

Common side effects of tadalafil include:

Headache
Indigestion
Back pain
Muscle aches
Flushing

Unique or Rare Side Effects

Both medications are not common to cause serious side effects, but it is good to know that it can happen. These problems do not happen often, but you should still know what they are. If you have cardiovascular disease, you should talk to your doctor about these side effects before you start the medicine.

One of the most serious side effects is priapism. This is when you get an erection that lasts more than four hours. If you do not treat it, it can do lasting damage.

Get medical help right away if you have any of these:

An erection that is over four hours (priapism)
Sudden loss of vision or hearing
Chest pain, dizziness, or nausea during sexual activity

Have Questions? Healthon Is Here to Help

Doctor reviewing patient history with male patient during consultation to choose between sildenafil and tadalafil for ED treatment

Selecting the appropriate erectile dysfunction medication requires individualized medical assessment. Healthon clinicians review medical history, lifestyle factors, and treatment goals to help patients choose the safest and most effective therapy.

Sildenafil is typically well suited for planned use with a shorter duration of action, while tadalafil offers extended coverage and greater flexibility for more frequent or spontaneous activity. Recognizing these differences supports informed discussions with a clinician and improves long-term treatment satisfaction.

Healthon’s clinical team provides expert guidance to help patients evaluate their options with confidence. To receive personalized recommendations and ongoing support, contact Healthon for professional care.

Frequently Asked Questions

Is sildenafil or tadalafil better for long-term use?

Tadalafil is seen as a good choice if you want something for everyday use. It has been approved for taking a small dose each day. This helps keep the medicine working in your body all the time and lets you have sexual activity whenever you want. You do not have to plan when you will take the dose or wait for it to work.

Can I take these ED meds with other drugs or health conditions?

You need to talk to your doctor. Some drugs can cause bad problems, especially if you take medicine for heart disease or high blood pressure like nitrates or alpha-blockers. Tell your doctor about your health and any other medicine you take. This helps stop big drops in blood pressure and other risk factors.

What makes a doctor recommend one over the other?

What a doctor suggests will depend on you. The main things they think about are how often you have sexual activity, whether you like being spontaneous or plan things, your health, and how you handle the side effect profile of each drug. The goal is to make sure you get patient satisfaction.