Cialis Dosage: When And How Much To Take
Written byJennifer Williamson, PharmD
Medically Reviewed byJennifer Williamson, PharmD
June 4, 2025 (Updated June 4, 2025)
Quick facts about Cialis
Generic drug/active ingredient: tadalafil
Available dosage strengths: 2.5 mg, 5 mg, 10 mg, 20 mg
Drug class: phosphodiesterase type 5 (PDE-5) blocker
Dosage form: oral tablet
Drug uses: erectile dysfunction (ED) and benign prostatic hyperplasia (BPH)
Cialis® is a brand name prescription medication that’s approved by the Food and Drug Administration (FDA) to treat erectile dysfunction (ED) or benign prostatic hyperplasia (BPH). It can also be used to treat people with both ED and BPH.
Cialis is a safe and effective treatment option for these conditions. It is also available in the generic version, tadalafil. Tadalafil contains the same active ingredient as Cialis and is just as safe and effective, but is usually more affordable.
Cialis uses, how it works, and dosage
Cialis or tadalafil for ED
Cialis and tadalafil are approved by the FDA to treat erectile dysfunction (ED). ED can happen when it’s difficult to achieve or maintain an erection. Cialis works to manage the symptoms of ED by Cialis blocking an enzyme in your body called phosphodiesterase type 5 (PDE-5). This causes the muscles of the penis to relax, which allows your blood vessels to open up and blood flow to the penis to increase. The increase in blood flow helps you to achieve and maintain an erection.
It’s important to note that Cialis will not work to cause an erection without sexual stimulation.
Cialis can be taken in two different ways to treat ED. Your doctor may recommend taking Cialis once daily or they may recommend taking the drug only as needed.
Cialis once daily for ED
If you take Cialis once daily, your starting dose will likely be 2.5 mg once daily. In some cases, your doctor may recommend increasing your dose to 5mg once daily.
Cialis as needed for ED
If you take Cialis as needed, you’ll usually start by taking a 10mg dose prior to sexual activity. In some cases, your doctor may increase your dose to 20 mg or recommend a lower dose of 5 mg, based on how the medication works for you and other factors that can affect your dose. So, the usual recommended dose of Cialis when it’s taken as needed is 5 mg to 20mg.
Cialis or tadalafil for BPH
Cialis and tadalafil are also FDA approved to treat BPH. BPH can occur when you have a enlarged prostate. This can cause urinary symptoms, such as urinary frequency or difficulty starting and stopping urinating. It’s not known exactly how Cialis works to treat the symptoms of BPH, but it’s believed that it can also relax the muscles in the bladder and prostate to help with BPH symptoms.
The recommended dose of Cialis when it’s taken for BPH is 5 mg once daily.
Cialis or tadalafil for ED and BPH
Cialis and tadalafil can also be used to treat people with both ED and BPH. This medication can work to alleviate symptoms of both of these conditions, so if you have both ED and BPH, you may be able to manage your conditions with just one pill.
If you’re taking Cialis for both ED and BPH, your doctor will likely recommend taking 5 mg once daily.
Tadalafil for PAH
Tadalafil may also help to treat PAH. PAH is a condition that causes increased pressure in the lungs. Brand name Cialis is not approved to treat PAH. Tadalafil can work to relax blood vessels in the lungs to help decrease the pressure. This can decrease your symptoms of PAH, such as shortness of breath, chest pain or fatigue.
Brand name Cialis isn’t approved for PAH. In fact, the brand of tadalafil that’s approved for PAH is called Adcirca. The usual dose of Adcirca or tadalafil for PAH is 40 mg once daily. However, this article will not focus on PAH since brand name Cialis is not approved for this use.
Cialis for daily use vs Cialis as needed: which is better?
Cialis and tadalafil are effective treatment options for ED whether you take the medication once daily or as needed. If you take Cialis as needed, you should take it at least 30 minutes before sexual activity to be sure that it has time to work. This may mean you have to plan ahead before having sex.
If you take Cialis for daily use, it can help manage your erectile dysfunction symptoms consistently. This means that you won’t need to worry about taking your dose prior to sexual activity and you can be more spontaneous. But, you’ll also have to remember to take your dose each day for the drug to be effective.
Your dose may be different if you take Cialis as needed compared to taking the drug once daily. People taking Cialis as needed will usually take a dose of 5-20 mg prior to sexual activity. People taking Cialis once daily may take 2.5-5 mg once daily.
If you have BPH and ED, your doctor will likely recommend that you take Cialis once daily, so that it can work to manage both conditions.
Below is a table of the advantages and disadvantages of taking Cialis for daily use vs. taking Cialis as needed:
| Advantages of Cialis for daily use | Advantages of Cialis as needed |
|---|---|
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| Disadvantages of Cialis for daily use | Disadvantages of Cialis as needed |
|
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If you have questions about which dosing option is best for you, talk to your doctor.
How to take Cialis for best results
In order to get the best results from Cialis or tadalafil tablets, be sure to take your medication exactly as prescribed by your doctor. They will either recommend taking your dose once daily at about the same time each day or 30 to 60 minutes prior to sex. You can take this medication with or without food.
You should also discuss your other medications and medical conditions with your doctor before taking Cialis. They can help to make sure that Cialis is safe for you and that there are no drug interactions.
Factors that affect your Cialis dosage
The condition that you’re taking Cialis for
Your dosage of Cialis may change based on the condition that you’re using Cialis for. For example, if you have ED, the recommended doses are usually 5 to 20 mg as needed or 2.5 to 5 mg daily. In comparison, if you’re taking the drug for BPH, your dose will likely be 5 mg once daily. Your doctor can determine the best dosage of Cialis for you based on your condition.
Other medications that you take
Cialis can interact with certain medications. Be sure to tell your doctor about any other prescription drugs, over-the-counter medications or supplements that you take before starting Cialis or tadalafil. Some medications that may interact with Cialis include:
- Nitrates
- Certain medications used to treat bacterial or fungal infections (antibiotics or antifungals), like ketoconazole
- Certain HIV treatments, like ritonavir
- Guanylate cyclase stimulators, like riociguat
- Alpha blockers, like doxazosin
- High blood pressure medications
Your doctor can help make sure that Cialis doesn’t interact with any of your other medications and that it’s safe for you to take. In some cases, if you take certain medications, your doctor may recommend a dosage adjustment of Cialis.
Medical conditions that may affect your Cialis dosage
Tell your doctor about any medical conditions that you have before starting Cialis or tadalafil. If you have certain medical conditions, your doctor may recommend taking a different dose of Cialis, or they may recommend a different ED treatment option. Medical conditions that you should discuss with your doctor include:
- Certain blood conditions, like sickle cell anemia or leukemia
- Abnormal penis shape, such as Peyronie’s disease
- Liver problems
- Kidney problems
- Stomach ulcers
- Vision loss or eye disease
- Certain heart conditions, such as a history of heart attack or hypertension
How you take Cialis for ED (as needed or once daily)
Your recommended dosage of Cialis may be determined by how you take the drug for ED. It’s possible to take Cialis once daily or as needed to treat ED. The recommended doses are usually 5 to 20 mg as needed or 2.5 to 5 mg daily. You and your doctor can discuss if you’d prefer to take Cialis once daily or as needed and the best dosage for you.
How well Cialis is working for you
The dosage of Cialis that you take may be based on how well the drug is working for you. For example, if you’re taking Cialis as needed, you’ll usually start by taking 10 mg once as needed prior to sex. But, your doctor may recommend increasing your dose to 20 mg if a dose of 10 mg isn’t working for you. They also may recommend decreasing your dose to 5 mg in some cases.
If you take Cialis once daily, you’ll usually start on a dose of 2.5 mg per day. But, if a dose of 2.5 mg daily isn’t working for you, your doctor may recommend increasing your dose to 5 mg daily.
Throughout your treatment with Cialis, your doctor may adjust your dosage of the medication to be sure that you’re getting the most from your Cialis.
Cialis vs. Viagra dosage
Cialis (tadalafil) and Viagra® (sildenafil) are both FDA approved treatment options for ED. In fact, PDE5 inhibitors like Cialis and Viagra are recommended by the American Urological Association to treat the symptoms of ED. Though Cialis and Viagra are both PDE5 inhibitors that work in similar ways to manage ED symptoms, the dosing of the drugs is different.
The dose of Cialis for ED depends on if you’re taking the drug as needed prior to sex or once daily. If you take Cialis prior to sex, your dose will usually be 5 to 20 mg taken prior to sex. But, if you take a once daily dose of Cialis, your dose will likely be 2.5 mg to 5 mg once daily. Cialis can work for up to 36 hours after taking your dose.
Viagra is only taken as needed prior to sex. It’s not recommended to take the drug once daily every day, unless you’re having sex. The recommended dose of Viagra is 25 to 100 mg prior to sex. The effects of Viagra usually only last for about 4 hours.
Below is a table comparing the recommended doses of Cialis vs. Viagra:
| Brand name | How it’s taken | Starting dose | Dosing ranges |
|---|---|---|---|
| Cialis | 30-60 minutes prior to sex with or without food | 10 mg | 5 mg - 20 mg |
| Once daily with or without food | 2.5 mg - 5 mg | 2.5 mg - 5 mg | |
| Viagra | 30-60 minutes prior to sex on an empty stomach or with a low fat meal | 50 mg | 25 mg - 100 mg |
If you have additional questions or would like to learn more about which medication may be best for you, talk to your doctor or healthcare professional for medical advice.
Common side effects of Cialis
Side effects of Cialis and tadalafil can occur, however they are usually mild. Examples of some common side effects to watch for include:
- Headache
- Indigestion
- Back pain
- Muscle pain
- Nasal congestion
- Flushing
- Pain in the arms or legs
- Low blood pressure
Although rare, it’s possible for serious side effects to occur from taking Cialis. Examples of serious side effects may include:
- Allergic reaction
- Prolonged erection or priapism
- Vision or hearing loss
If you have questions or concerns about possible side effects of Cialis, discuss them with your doctor or pharmacist. Although rare, it is possible for side effects to occur. If you do experience side effects while taking Cialis, your doctor or pharmacist may also be able to recommend ways to decrease the side effects from occurring while taking Cialis.
Frequently asked questions
If you miss your dose of Cialis and you take the drug once daily, take your dose as soon as you remember. But, if it’s almost time for your next dose of Cialis, skip your missed dose and take your dose at the regularly scheduled time. Never take two doses of CIalis to make up for a missed dose. Taking too much Cialis can increase your risk of side effects occurring, and some side effects may be serious.
If you missed a dose of once daily Cialis and you’re not sure when to take your next dose, talk to your doctor or pharmacist. Cialis for once daily use works best when it’s taken at about the same time each day. If you need help remembering to take your dose of Cialis each day, try setting an alarm or using a medication reminder application.
If you take Cialis as needed and you forgot to take your dose prior to sex, skip the missed dose. Take a dose of Cialis prior to the next time you have sex.
Key Takeaways
- Cialis and generic tadalafil are FDA approved to treat erectile dysfunction (ED) and BPH.
- Dosing of Cialis depends on if you’re taking the drug as needed prior to sex or once daily: As needed dosing is usually 5 to 20 mg 30 to 60 minutes prior to sex and once daily dosing is usually 2.5 to 5 mg daily.
- Many factors may affect your Cialis dosage, including what you’re taking it for, other medications that you take, other health conditions that you have, how well the drug is working for you and how you take your dose.
- For more information about Cialis, see your doctor or visit Motivated.com where you can be connected with a doctor and have ED medications delivered discreetly to your door.
This article offers general information and is not intended as medical advice. It does not replace the expertise of a licensed healthcare professional, who should be consulted regarding any medical questions or treatment decisions. Always seek personalized guidance from your doctor before starting or changing any treatment. While efforts are made to ensure accuracy, the content may not address all potential risks, possible uses or benefits.
