Cialis
Cialis (tadalafil) is a prescription treatment for erectile dysfunction (ED), designed to improve blood flow and help maintain an erection for up to 36 hours.
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Cialis is an erectile dysfunction medication that helps you achieve a harder, longer-lasting erection for sex by improving blood flow to the penis. It can be prescribed if you have erectile dysfunction (ED). Cialis is a branded tablet that contains the active ingredient tadalafil and is available as a single 10 or 20mg tablet taken before sex that remains effective for up to 36 hours. Because of how long it lasts, it’s often nicknamed the ‘weekend pill’, though Cialis can also be taken daily at lower 2.5mg or 5mg doses.
In clinical trials, Cialis has been proven to work for 81% of people. It’s taken 30 to 60 minutes before sex and takes around this long to work. Cialis is manufactured by Eli Lilly and Company Limited.
Prices
4 tablet(s) - £44.97
8 tablet(s) - £79.97
12 tablet(s) - £119.97
16 tablet(s) - £146.97
4 tablet(s) - £44.97
8 tablet(s) - £87.97
16 tablet(s) - £147.97
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Cialis is a treatment for erectile dysfunction (ED), used to help you get and maintain an erection for sexual activity. Cialis contains the active ingredient tadalafil, which belongs to a group of medications called phosphodiesterase type 5 (PDE-5) inhibitors, like Viagra and other ED tablets. It’s taken around 30 to 60 minutes before sex and is also found under the generic name tadalafil.
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Cialis works by helping the blood vessels in your penis relax, allowing for increased blood flow and improved erections. However, it does not cause a spontaneous erection. This means it will only work following sexual stimulation, meaning you and your partner will still need to engage in foreplay.
How long does Cialis take to work?
Cialis takes around 30 to 60 minutes to help you get an erection. It might take longer if you have it with a large meal, as the absorption of the tablet in your stomach will be slower.
How long does Cialis last?
Cialis lasts up to 36 hours. For this reason, it's been nicknamed the ‘weekend pill’, because if taken on Friday night, it can last until Sunday morning.
How effective is Cialis?
In clinical studies, Cialis has been proven, on average, to improve erections for 81% of people, compared to 35% who took a placebo. Across the different severity categories of ED, the following percentage of patients reported improvements with Cialis:
- 86% of those with mild ED
- 83% with moderate ED
- 72% with severe ED
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Take Cialis 30 to 60 minutes before you want to have sex. During this time, you can engage in foreplay to help Cialis work, as you need to be sexually stimulated. The tablet is swallowed whole, with water, and with or without food. Try to avoid large meals right before taking it, as it may take longer to work.
Do not take more than 1 dose of Cialis in 24 hours. 10mg and 20mg doses of Cialis are not meant to be taken daily. Speak to your doctor about the daily dose if this would be better for your lifestyle.
Cialis 10mg
The recommended starting dose is one 10mg tablet before sexual activity. Only take the dosage you’ve been prescribed. It’s recommended to try Cialis on 8 different occasions first, as it might take a few times to work.
Cialis 20mg
Cialis 20mg is the highest dose of Cialis prescribed, and only if Cialis 10mg does not work for you after trying it 8 different times. It may also be prescribed if you have severe ED.
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Cialis can cause some side effects, but not everyone will get them. They are more likely when you first start treatment, and should get better after taking a few doses.
Common Cialis side effects (seen in 1 to 10 out of every 100 patients) include:
- indigestion
- headache
- pain in the arms and legs
- aches in the muscles
- pain in the back
- congestion in the nasal passages
- flushing of the face
Uncommon Cialis side effects (seen in 1 to 10 out of every 1,000 patients) include:
- general fatigue or tiredness
- swelling in the hands, feet, or ankles
- a ringing sensation in the ears
- bleeding from the nose
- extended or prolonged erection
- blood in the urine (pee)
- shortness of breath or breathing difficulties
- discomfort or pain in the eyes
- blurred vision
- acid reflux
- feeling or being sick (nausea or vomiting)
- stomach discomfort
- lightheadedness or dizziness
- elevated or lowered blood pressure
- sensation of a pounding or rapid heartbeat
Rare Cialis side effects (seen in 1 to 10 out of every 10,000 patients) include:
- excessive or increased perspiration (sweating)
- blood in the semen
- bleeding from the penis
- hives or itchy, red raised patches on the skin
- sudden reduction or complete loss of hearing
- redness of the eyes
- puffiness or swelling around the eyelids
- seizures or temporary memory loss
- loss of consciousness or fainting
- partial, temporary, or permanent decrease or loss of vision in 1 or both eyes
- heart attack and stroke in men with previous heart problems
Other rare Cialis side effects reported in men that were not identified during clinical trials include:
- migraines, facial swelling, and serious allergic reactions
- severe skin rashes
- conditions affecting blood flow to the eyes
- angina
- irregular heartbeat
- sudden cardiac death
- distorted, dimmed, blurred, or a sudden decrease in vision (frequency unknown)
If you get any of the following serious side effects, speak to a doctor, go to A&E, or call 999 in an emergency straight away:
- changes in vision (frequency unknown)
- unexpected loss of sight (rare)
- an erection lasting 4 hours or more, known as priapism, which may also be painful (rare)
- pain in the chest – do not take nitrates even if you have been prescribed them and speak to a doctor straight away (uncommon)
- palpitations or the sensation of a fast heart rate
- skin rashes or other signs of an allergic reaction (uncommon)
- a severe allergic reaction, which can cause difficulty breathing, swelling in the face and throat, dizziness, and fainting (rare)
- sudden changes in your speech or weakness or numbness in your face, arms or legs
For a full list of side effects, you can also read the patient information leaflet that comes with your medication.
How long do Cialis side effects last?
Cialis side effects should get better as your body gets used to the treatment. This means you may need to take it a few times. Always report side effects to your doctor, especially if they do not get better or are severe.
What to do if you get Cialis side effects
Some common side effects can be managed at home if they are mild, for example, manage:
- indigestion, by taking Cialis with a light meal, avoiding greasy, spicy foods, alcohol, and caffeine
- headache, by taking over-the-counter painkillers, avoiding alcohol, and drinking plenty of water
- pains and muscle aches, by taking over-the-counter painkillers and resting if needed
- nose congestion, by using an over-the-counter nasal congestion spray
- facial flushing, by keeping the room cool with a fan, avoiding strenuous activity until it passes, and having a cool shower
Serious side effects should be discussed with a doctor straight away. You can also call 111 or 999 in an emergency, or go to your nearest A&E department.
Are there long-term side effects of Cialis?
Some side effects may continue as you take the medication, such as high or low blood pressure. However, this should get better once you stop taking Cialis. Some serious side effects of Cialis may be permanent, though this is rare, such as a decrease or loss in vision.
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Cialis may be suitable if you’re over 18, are a man, and have been diagnosed with ED. It’s important that you only use Cialis if you have ED, or it could be unsafe or cause erection problems.
Some conditions may make Cialis unsuitable, so speak to your doctor if you have:
- heart disease – sexual activity adds additional strain on the heart, increasing the risk of serious side effects
- uncontrolled blood pressure issues
- had a stroke recently
- a serious liver problem
- a deformation of your penis
- a severe kidney problem
- leukaemia (cancer of the blood cells)
- multiple myeloma (cancer of the bone marrow)
- sickle cell anaemia (an abnormality of red blood cells)
- non-arteritic anterior ischaemic optic neuropathy
- severe kidney disease
As Cialis can cause dizziness, do not drive or operate machinery until you feel better.
It’s not known if Cialis is effective in people who have had:
- pelvic surgery
- a radical non-nerve-sparing prostatectomy (removal of all or part of the prostate gland, where the nerves are cut)
Cialis also contains lactose, so speak to your doctor if you have a lactose intolerance and do not take Cialis if you have been diagnosed with a lactose allergy.
Taking Cialis with other medications
Cialis may not be suitable if you take:
- all nitrate medications, such as glyceryl trinitrate, isosorbide dinitrate, and recreational nitrates (poppers)
- other treatments for erectile dysfunction – you should never take more than 1 ED treatment at a time, as this increases the risk of serious side effects
- medications used to treat certain infections, such as rifampicin, erythromycin, clarithromycin, or itraconazole
- medications such as ketoconazole tablets to treat fungal infections
- protease inhibitors for the treatment of AIDs or HIV
- a 5-alpha reductase inhibitor, used to treat benign prostatic hyperplasia
- riociguat, for high blood pressure in the arteries
- other high blood pressure treatments
- an alpha blocker (mainly doxazosin), used to treat high blood pressure or urinary symptoms associated with benign prostatic hyperplasia
We recommend avoiding grapefruit juice while taking your tablets because it may affect how Cialis works.
Let your doctor know if you are taking any medications when considering Cialis as it’s important to check Cialis is suitable for you. It’s important to also read the patient information leaflet enclosed with your Cialis.
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You can get Cialis prescribed from a regulated online service, such as Asda Online Doctor. It may also be prescribed on the NHS, but you’re more likely to get the unbranded version, tadalafil. There is a form of Cialis you can get over the counter called Cialis Together, which comes in 10mg tablets.
Can I buy Cialis online?
Yes. You can get Cialis online from a regulated and trusted service, such as Asda Online Doctor. Ordering Cialis through Asda Online Doctor is a straightforward process, and you do not need to have a face-to-face appointment:
- Complete a brief medical questionnaire – provide details about your health so our doctors can make sure Cialis is safe and suitable for you.
- Doctor review and assessment – one of our doctors will check your answers to determine if Cialis is the right treatment for you.
- Fast and discreet delivery – if your request is approved, your medication will be sent directly to your door in discreet, unmarked packaging. Alternatively, you can choose to collect it from your local Asda Pharmacy in as little as 2 to 3 hours.
We are fully monitored and regulated, so you can be sure you’re receiving genuine and safe medication. Our confidential online ED service can help you get the treatment you need to improve your sex life if you’d rather not speak to a doctor in person.
Can I buy Cialis over the counter?
You cannot get Cialis over the counter, but you can get Cialis Together. This is a pharmacy-only treatment containing 10mg tablets, to be used in the same way as Cialis 10mg. It’s an ‘on demand’ treatment.
Even though you do not need a prescription, your pharmacist will still need to do a quick consultation to make sure it’s a safe and suitable medication.
Can I get Cialis on the NHS?
Yes, you can get unbranded Cialis on the NHS, which is called tadalafil tablets. They are the same medication, just cheaper. You’ll need to have a consultation with your GP to get a prescription.
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There are plenty of alternatives to Cialis, though Cialis is the only tablet that lasts 36 hours, except tadalafil (generic Cialis). The main differences between Cialis and tadalafil are that Cialis is branded, so may cost more, and they are made by a different manufacturer. They still contain the same active ingredient in the same doses, and work in the same way.
Other ED treatments available at Asda Online Doctor include:
PDE-5 inhibitor tablets
Most ED treatments contain a PDE-5 inhibitor, which means they work in the same way to improve blood flow to the penis. Usually, the main difference is their active ingredients, how long they take to work, and how long they last.
Alternative ED tablets to Cialis include:
- sildenafil, one of the most common treatments for ED, is available as a generic tablet or as the branded medications Viagra and Viagra Connect. These treatments typically take 30 to 60 minutes to work and remain effective for 4 to 6 hours. Viagra Connect can also be purchased over the counter, though it’s only available in a 50mg dose.
- Spedra, a branded ED medication containing the active ingredient avanafil. It’s fast-acting, taking 15 to 30 minutes to start working and lasting for around 4 hours.
- Vardenafil, a generic treatment that is also sold under the brand name Levitra. Both work in the same way, taking up to 60 minutes to become effective and lasting between 4 and 6 hours.
PDE-5 inhibitor sprays
As well as tablets, sildenafil (the active ingredient in Viagra) is now available as a mouth spray called Hezkue. This is a mint-flavoured mouth spray which is taken by spraying the recommended dose onto the tongue and swallowing it straight away with saliva. It should be used around 60 minutes before sex, but can take effect in as little as 12 minutes and lasts for 4 to 5 hours.
ED cream
The other treatment available for ED is called Vitaros cream. This is not a PDE-5 inhibitor and instead contains the active ingredient alprostadil, a type of medication called a prostaglandin. Vitaros works by widening the blood vessels in your penis to increase blood flow, helping you to get an erection.
It’s applied directly to the opening of your penis using an applicator and takes 5 to 30 minutes to work. It is effective even if you have nerve damage and can last for 1 to 2 hours.
Cialis vs Viagra
Cialis and Viagra (tadalafil and sildenafil) are both PDE-5 inhibitors, so they work in the same way. They also take 30 to 60 minutes to take effect. The main differences are that:
- Cialis lasts up to 36 hours, while Viagra lasts 4 to 6
- they have different doses, because the active ingredient is different – just because Viagra has a higher dosage this does not make it more effective
- Cialis also has a daily version, while Viagra can only be prescribed as needed
When comparing effectiveness, Viagra 50mg is effective for an average of 74% of men, while Cialis 20mg is effective for an average of 81%.
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Frequently asked questions
What is the generic version of Cialis?
The generic version of Cialis is tadalafil. This can be prescribed in the same doses (both ‘on demand’ and daily) and contains the same active ingredient. The difference is the manufacturer. Generic versions of the same treatment are usually cheaper.
Does Cialis make you last longer?
Cialis can make your erections last longer, but it cannot make you last longer in bed. If you ejaculate quickly, you may have a condition called premature ejaculation, which Cialis does not treat. However, erectile dysfunction and premature ejaculation can happen together, so treating one may help manage the other.
You should speak to your doctor about premature ejaculation treatment if you think you have the condition, as medication is available to help.
How can I get the maximum effect from Cialis?
To get the maximum effect from Cialis, you should:
✔ be sexually stimulated – remember that the medication helps you get an erection, but still requires sexual arousal to work
✔ watch your intake – avoid drinking too much alcohol and large, high-fat meals before taking your tablet, as these can reduce effectiveness, and alcohol also affects sexual performance
✔ make healthy lifestyle changes – regular exercise and managing lifestyle factors like quitting smoking can help with ED, which directly impacts the blood flow to your penis
✔ manage expectations – if you have performance anxiety, focus on relaxation techniques to help the medication be more effective during sexual activity
If Cialis does not work after trying it on 8 different occasions and trying these tips, speak to your doctor.
Can I drink alcohol while taking Cialis?
Yes, but it’s recommended to avoid drinking heavily. It’s also a good idea to take Cialis for the first few times without alcohol, because it may reduce its effectiveness and increase the chance of side effects. Alcohol can affect blood flow to the penis, which affects sexual performance.
Does Cialis increase libido?
No, Cialis is not known to increase your libido (sex drive). However, some people may find their libido increases when ED is managed with treatment, as it can remove or reduce performance anxiety around getting and keeping an erection.
How long does Cialis stay in your system?
The half-life of Cialis, which is how long it takes for the active ingredient to reduce by half in your body, is 17.5 hours. It can still work for up to 36 hours, but the effects will wear off around then.
What is Cialis Together?
Cialis Together is an over-the-counter version of Cialis, available in 10mg tablets only. You’ll still need a consultation with a pharmacist to get it, but you can get it without a prescription from a doctor.
What is Cialis Daily?
Cialis Daily is a daily pill available for ED. Taking Cialis Daily means you’ll be ready for sex at any time, and do not have to plan to take a pill just before sex. Cialis Daily is recommended for people who have sex 3 or more times a week. If you have sex less frequently than this, the ‘on demand’ Cialis pill may be more suitable.
Cialis Daily comes in 2 doses: 2.5mg (starting dose) and 5mg (highest dose). It’s taken once a day, at the same time each day, and continues to work as long as you take it. Cialis Daily should be swallowed whole, with water, and with or without food.
Crystal qualified in Medicine at Barts and the London School of Medicine and Dentistry in 2010. She then trained as a GP in London hospitals and practices. She has a particular interest in reproductive, sexual, and women’s health.
Meet our doctorsLast reviewed: 24 Apr 2026
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