Are Tadalafil and Sildenafil the same?

Friday, March 14, 2025

Tadalafil and Sildenafil may appear similar and that’s because they are in many ways. However, there are also a few differences that you should be aware of.

This article will help you delve deeper into the differences and similarities of these two drugs. We will look at how long they take to work, how long they last, and their different strengths and how to take them.

Tadalafil vs. Sildenafil

Sildenafil was released to the market in 1998 and has become one of the most-prescribed medicines in human history. Millions of people have taken it, including those looking to treat erectile dysfunction (ED) (1).

Tadalafil came along in 2003. Eli Lilly, a major drug company, marketed it under the name Cialis, and it later became a generic medication, lowering the cost.

Doctors often recommend Sildenafil and Tadalafil interchangeably. But their differences mean that you may prefer one to the other. Both Sildenafil and Tadalafil are in a group of medicines call PDE5-inhibitors.

Here are some of the key differences between the two drugs:

Time they take to start working

Sildenafil and Tadalafil take a similar amount of time to work.

For most people, Sildenafil begins to act within 30 to 60 minutes, with peak effects reached at around one hour. (Taking the medicine with or after a high-fat meal can mean it takes longer to act, but it will still have an effect).

Tadalafil works similarly, within 30 to 60 minutes, but can take up to two hours to reach a peak. Food doesn’t affect its absorption as much, so it can be more predictable.

Practically speaking, time-to-onset differences are minimal when considering Sildenafil vs Tadalafil. Taking either will work in a similar way.

How long they last

The primary difference between Sildenafil and Tadalafil is how long their effects last. This is why Eli Lilly developed the drug in the first place.

Sildenafil’s effects last from 4 to 6 hours, so sexual activity can occur during that window. After that, the drug will wear off and may not produce noticeable effects.

Tadalafil is different. Its effects can last up to 36 hours (a day and a half), which is why some individuals call it “the weekend pill.” Taken Friday night, the effects can last until Sunday morning.

You can take Tadalafil daily as a 5mg tablet which allows for continuous effects (i.e. spontaneous sex at any time of day or night). The drug takes around a week to build up in the body, at which point it permanently improves penile blood flow.

Dosing Schedules

The dosing schedules for Sildenafil and Tadalafil are slightly different, given their side-effect profiles and how they work once they enter the body.

Sildenafil dosing

You should take Sildenafil when you anticipate sexual activity.

Most people take between 50 and 100mg around 30 to 60 minutes before sex. If you have never used Sildenafil before, you must start with 50mg.

You should only take one tablet daily, even if you feel its effects wearing off.

Tadalafil dosing

Tadalafil can be taken “as needed” or daily.

If you take it as needed, a typical dose is 10 to 20 mg taken 30 to 60 minutes before sexual activity (similar to Sildenafil). Again, you should only take this a maximum once per day(2).

If you take Tadalafil daily, you will take 5 mg at the same time every day. After around a week, levels of the medication will build up in the body sufficiently to allow erections at any time. As such, you won’t need to plan the medication timing.

What happens when you take Tadalafil and Sildenafil together?

You should not take Tadalafil and Sildenafil together. Combining the drugs (which work in similar ways to increase blood flow to the penis) leads to increased risks.

For example, there is a higher likelihood of side effects like low blood pressure. Sildenafil and Tadalafil can cause lightheadedness and dizziness, sometimes leading to fainting(2,3).

Long and painful erections lasting more than four hours could be a problem. These require emergency medical attention to prevent permanent damage to the penis.

Other common side effects, such as flushing, nasal congestion, and headaches, could also become more likely. These symptoms are typical among people taking PDE5 inhibitors but could become worse if they are taken together.

There is no clear evidence that taking these medications together offers any benefits. As such, most medical practitioners believe combining them brings risks that outweigh the benefits. These drugs may have unknown interactions with each other or other medicines you are taking and could lead to potentially dangerous drops in blood pressure.

If you are considering taking Tadalafil or Sildenafil, speak to us. If you are having trouble with one treatment, we may recommend trying the other.

It’s normal for a medicine to not work the way you want sometimes. If this happens, we can give you our free, expert guidance.

Tadalafil or Sildenafil: which is better?

Whether you should take Tadalafil or Sildenafil depends on your medical history and current requirements. Mostly, their effectiveness is similar, so they are equally good at helping you maintain erections. However, individual responses may be different. You may find that Sildenafil works better than Tadalafil for you, or vice versa.

The time they take to work is also similar. Sildenafil and Tadalafil start acting on penile tissue within 30 to 60 minutes. However, Tadalafil may work slightly better if you eat food at the same time. As such, it could be a better option if you anticipate sexual activity after a large meal.

Duration is quite different, with Sildenafil lasting 4 to 6 hours and Tadalafil around 36 hours. As such, the latter may be a better choice for some people.

Ultimately, Tadalafil and Sildenafil are not the same. However, there is no universally “better” choice for everyone, which is why both drugs are still on the market. Many people begin with sildenafil and then move to tadalafil if necessary, but not always.