If you have erectile dysfunction (ED) or benign prostatic hyperplasia (BPH), your doctor might suggest Cialis (tadalafil) as a treatment option for you.

Cialis is a prescription medication that’s used to treat ED and symptoms of BPH (such as urination problems) in adult males.* It can also be used if you have both of these conditions.

Cialis comes as a tablet that you’ll swallow whole. Cialis belongs to a group of drugs called phosphodiesterase 5 (PDE5) inhibitors. These drugs treat ED by relaxing blood vessels to increase blood flow into the penis. For BPH symptoms, they relax the bladder muscles, allowing urine to flow more easily.

This article describes the dosages of Cialis, including its form, strengths, and how to take the drug. To learn more about Cialis, see this in-depth article.

Note: This article covers typical dosages of Cialis, which are provided by the drug’s manufacturer. But when using Cialis, always take the dosage that your doctor prescribes.

* In this article, we use the term “male” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Get answers to common questions about the dosage of Cialis.

What form does Cialis come in?

Cialis comes as a tablet that you take by mouth.

Available strengths of Cialis (2.5 mg, 5 mg, 10 mg, 20 mg)

Cialis tablets come in four strengths: 2.5 mg, 5 mg, 10 mg, and 20 mg.

What are the typical dosages of Cialis?

Typically, your doctor will start you on a low dosage. Then they’ll adjust your dosage over time to reach the right amount for you. Your doctor will ultimately prescribe the smallest dosage that provides the desired effect.

If you have certain kidney or liver problems, your doctor may prescribe a low dosage for you. This is because the normal dosage may increase the risk of side effects with your condition.

The information below describes the usual dosage recommendations for Cialis. But be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for erectile dysfunction (ED)

There are two dosage options when Cialis is used to treat ED: dosage for occasional use and for daily use.

Occasional use for ED

With occasional use, you’ll take Cialis only as needed. You’ll likely take one 10-mg tablet before having sex.

Depending on how well the 10-mg dose works for your ED, your doctor may adjust your dose. It may be decreased to 5 mg or increased to 20 mg. You’ll continue to take it only as needed before sex.

You should not take Cialis more than once per day. You also should not take more than the recommended maximum dosage of Cialis, which is 20 mg per day. Taking higher dosages of Cialis than this, such as 40 mg per day, raises your risk for serious side effects. Examples of these side effects include very low blood pressure and priapism (a painful erection lasting 4 hours or longer).

Daily use for ED

With daily use, you’ll take one dose of Cialis per day. You don’t need to time your dose to be taken before having sex. You should take it around the same time each day.

For daily use of Cialis for ED, the usual starting dosage is 2.5 mg per day. If this dosage isn’t effective for you, your doctor may increase your dosage to 5 mg per day.

Dosage for benign prostatic hyperplasia (BPH)

The usual dosage of Cialis for BPH symptoms is 5 mg once daily for up to 26 weeks. You should take your dose around the same time each day.

Dosage for ED and BPH

If your doctor prescribes Cialis to treat ED along with BPH symptoms, you’ll take Cialis once daily.

For this use, the usual dosage is 5 mg per day. You should not take any additional doses of Cialis for occasional use before sex.

You don’t need to time your dose to be taken before having sex. You should take it around the same time each day.

Is Cialis used long term?

Yes, Cialis is typically used as a long-term treatment. If you and your doctor determine that it’s safe and effective for you, it’s likely that you’ll use Cialis long term.

Dosage adjustments

If you have certain kidney or liver problems, your doctor may prescribe a lower dosage of Cialis for you. This is because with your condition, the usual dosage may raise your risk for side effects from the drug.

Depending on how severe your kidney or liver problems are, your doctor may recommend occasional dosing instead of daily dosing to treat ED.

How can I get the maximum effect from Cialis?

To get the maximum effect from Cialis, take it exactly as prescribed.

If you’re using once-daily Cialis for either erectile dysfunction (ED) or benign prostatic hyperplasia (BPH), take your dose around the same time each day. This helps keep a consistent amount of the drug in your body to provide the maximum effect. If you forget to take doses, skip doses, or take doses late, the medication won’t work as well.

If you’re prescribed occasional (as needed) Cialis for ED, it’s best to take your dose at least 2 hours before having sex. This is because it takes an average of 2 hours for the drug to reach its highest level in your body.

Because this is an average, you may notice better effects if you have sex a little sooner or a little later than this 2-hour timeframe. In studies, Cialis improved erectile function as soon as 30 minutes to as long as 36 hours after a dose was taken. As long as you do not take more than the maximum daily dose, you can experiment with how long you wait to have sex after taking a dose.

If you have other questions about how to get the most from Cialis, talk with your doctor or pharmacist.

If I take 5 milligrams (mg) of Cialis daily, how long does it take the drug to work?

Cialis starts working quickly. Studies show that the drug begins to work 30 minutes to 6 hours after you take your first dose. But it may take several days for the medication to reach its full effectiveness. If you don’t notice an improvement in your BPH symptoms or ED within a week of daily use, talk with your doctor. They may need to adjust your dosage.

Could I take an 80-mg dose of Cialis?

No, it’s not safe to take an 80-mg dose of Cialis. The maximum recommended daily dosage of Cialis is 20 mg per day if you take it as needed for ED. If you take Cialis daily, the maximum dosage is 5 mg per day.

Taking doses of Cialis above the recommended limit could lead to serious side effects, such as dangerously low blood pressure or priapism (a painful erection lasting 4 hours or longer).

What’s the typical Cialis dosage for a 70-year-old?

Cialis dosage is not based on your age alone. Instead, your doctor will prescribe the dosage that’s best for your condition. Before prescribing Cialis, your doctor may send you for a blood test to check how well your kidneys and liver are working. This is because they’ll take your kidney and liver health into consideration when determining your dosage.

For many people, their kidneys may not work as well as they age. So if you’re an older adult (ages 65 years and older), it may take longer for your body to break down and clear Cialis from your system. Older adults may also be more sensitive in how they react to Cialis, which may increase their risk for side effects.

If you’re 70 years old, your doctor will likely start you on a low dosage of Cialis. If it works well for you, you’ll probably continue taking a low dosage. If it doesn’t work well for you or you develop bothersome side effects, your doctor will adjust your dosage. The goal is to find the lowest dosage that effectively treats your BPH symptoms or ED without causing bothersome side effects.

If you have questions about what your Cialis dosage should be, talk with your doctor.

How do the dosages for Cialis and Viagra compare?

As ED treatments, both Cialis and Viagra can be taken occasionally (as needed) before sexual activity. The usual dosage for occasional Cialis use is one dose 2 hours before having sex. The usual dosage for occasional Viagra use is one dose 1 hour before having sex.

Cialis is also approved for once-daily dosing for ED, but Viagra is not. This is because the effects of Cialis on ED can last much longer than Viagra’s effects. One dose of Cialis can help improve erectile function for up to 36 hours. In comparison, Viagra’s effects can last up to 4 hours. But on average, its effects start to lessen 2 to 3 hours after you take a dose.

The typical dose for once-daily Cialis for ED is 2.5 milligrams (mg) to 5 mg. When used as needed for ED, the usual Cialis dose is 10 mg (with a maximum daily dose of 20 mg). The typical dose of Viagra for ED is 50 mg.

Talk with your doctor about whether Cialis or Viagra may be a better option for you.

You’ll take Cialis by mouth, either once daily or occasionally (as needed before sex).

The Cialis tablet should be swallowed whole. You can take it with or without food.

With once-daily Cialis, be sure to take it around the same time each day. When you’re taking Cialis once a day, there isn’t a best time to take Cialis. But taking your dose around the same time each day helps to keep a steady level of the drug in your body.

With occasional (as needed) use of Cialis, it’s recommended that you take your dose about 2 hours before having sex. This is because it takes an average of 2 hours for the drug to reach its highest level in your body.

Because this is an average, you may notice better effects if you have sex a little sooner or a little later than this 2-hour timeframe. In studies, Cialis improved erectile function as soon as 30 minutes to as long as 36 hours after a dose was taken.

If you have questions about taking Cialis, talk with your doctor or pharmacist.

Do not use more Cialis than your doctor prescribes. Using more than this can lead to serious side effects.

What to do in case you take too much Cialis

Call your doctor right away if you think you’ve taken/used too much Cialis. You can also call 800-222-1222 to reach the American Association of Poison Control Centers, or use their online resource. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.

The dosage of Cialis you’re prescribed may depend on several factors. These include:

  • the type and severity of the condition you’re using Cialis to treat
  • your age
  • other conditions you may have, such as kidney or liver problems (see “Dosage adjustments” under “What is Cialis’s dosage?”)

If your doctor prescribes once-daily Cialis for your condition, it’s best to take it around the same time each day. If you miss a dose, take it as soon as possible.

However, you should not take more than one dose of Cialis per day. Doing so could raise your risk for side effects, such as low blood pressure or priapism (a painful erection lasting 4 hours or longer).

If you need help remembering to take your dose of Cialis on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone. A kitchen timer can work, too.

The sections above describe the typical dosages provided by the drug manufacturer. If your doctor recommends Cialis for you, they’ll prescribe the dosage that’s right for you.

Remember, you should not change your dosage of Cialis without your doctor’s recommendation. Only take Cialis exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

  • How long should I give Cialis a chance to work before talking with my doctor about adjusting my dosage?
  • Is once-daily or occasional dosing of Cialis more effective for erectile dysfunction?
  • How can I tell if my Cialis dosage might need to be lowered?
  • Would a different dosage raise or lower my risk for side effects from this drug?

For information about nutrition, sex, stress relief, and more, sign up for Healthline’s men’s health newsletter.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.