Cialis vs Viagra: Differences & Which is Best For You?

Cialis and Viagra are examples of phosphodiesterase type-5 (PDE-5) inhibitors that are used to treat erectile dysfunction. They work by increasing blood flow to the penis to help you get an erection that’s hard enough for sex. They have a similar rate of effectiveness, Viagra 50mg is effective for around 74% of men while Cialis at various doses can help 75% of men get an erection.

Although they belong to the same class of medication, there are some differences between Viagra and Cialis which may help you choose one over the other, including their cost and how long they remain effective for.

Cialis and Viagra are similar in that they are medications used to treat erectile dysfunction. Here we’ll explore how Cialis and Viagra are similar.

Prescription-only status

They are both prescription-only medications which means you must have a prescription from a doctor in order to obtain them. A doctor will assess if Cialis or Viagra are suitable for you to take based on your medical and lifestyle history.

PDE-5 inhibitors

Both Cialis and Viagra belong to a class of medications called phosphodiesterase type 5 (PDE-5) inhibitors that are used to treat erectile dysfunction.

Although they contain different active ingredients, Cialis and Viagra have a similar chemical composition and work in exactly the same way by relaxing the smooth muscles in the penis to increase blood flow, and enable you to get and keep an erection.

Generic versions available

Cialis and Viagra are the names of the branded medications but their generic versions contain the same active ingredients, are available in the same dosages, and work in the same way – tadalafil (Cialis) and sildenafil (Viagra).

The difference between the branded and generic versions are their branding and marketing, and pricing; generic versions are cheaper.

Over-the-counter versions

Both Viagra and Cialis have over-the-counter versions available, which means you can buy them from a pharmacy without a prescription.

Viagra Connect is the over-the-counter version of Viagra and contains 50mg of sildenafil. At this dose, the active ingredient has been shown to be effective in 74% of men and can last 4 to 6 hours. However, unlike prescription-only Viagra, 50mg is the only dose available and it is only available in packs of 2 pills rather than 4.

Cialis Together is available without prescription in 10mg doses. This dose is effective for 60% to 70% of men and can last for up to 36 hours.

Although Cialis and Viagra are effective treatments for erectile dysfunction that work in similar ways, there are some differences:

Side effects

Like all medications Viagra and Cialis may cause side effects in some people. However, they are more common in people who take higher doses.

The most common side effects of Viagra and Cialis are compared in the table with similar side effects in bold:

Note: Viagra and Cialis cannot be taken with medication, including nitrates which are often used to treat cardiovascular diseases. Before taking Cialis or Viagra, check with your doctor to be sure that you are not taking medications that may induce unwanted side effects when taken alongside Cialis or Viagra.

Are you more likely to get side effects from Cialis or Viagra?

Cialis and Viagra can both cause side effects but most are mild and should go away once your body adjusts to treatment. Although serious side effects are rare, they are possible. Because both medications belong to the same class of drug, their side effects are similar. However, because Cialis is effective for longer than Viagra, it is possible that if you experience side effects they may also last for longer.

What to do if you get side effects

If you experience side effects while taking Viagra or Cialis, you should let your doctor know. If you find the side effects difficult to manage, you may be able to switch to a lower dose. For example, Viagra and Cialis are available in lower doses that contain half the amount of their active ingredient present in their standard doses.

If you are on the standard 50mg dose of Viagra, your doctor can reduce the dose to 25mg. With Cialis, the lowest available dose is 2.5mg, which is a daily dose. If you need an on-demand dose, the lowest dose is 10mg.

If the side effects are still difficult to tolerate, your doctor may advise alternative erectile dysfunction treatments.

Cialis may work slightly faster than Viagra, although the difference is small. Cialis can start working within 30 minutes, while Viagra usually takes 30 to 60 minutes. For the best results, Viagra should generally be taken around one hour before sex, whereas Cialis should be taken at least 30 minutes beforehand.

Lower-dose Cialis can also be taken once daily at approximately the same time. Once stable levels have built up, it remains available to work throughout the day, meaning you do not need to time each tablet around sex. However, both Cialis and Viagra require sexual stimulation to produce an erection.

Food does not significantly affect how quickly Cialis works, so you can take it with or without a meal. Viagra works best on an empty stomach because eating beforehand, particularly a high-fat meal, may delay its effects.

Viagra and Cialis are similarly effective. In clinical trials, 87% of people were satisfied with tadalafil (20mg) compared to 46% of those given a placebo. Viagra, on the other hand, was effective for:

• 62% of people given a 25mg dose
• 74% of people given a 50mg dose
• 82% of people given a 100mg dose

In comparison, 25% reported improvements on Viagra when taking a placebo.

However, in real-world scenarios, both medications are similarly effective. The treatment that works best depends on your individual response, dose, current health, and if you take it correctly.

For the best results, follow the instructions provided with your medication. Both treatments require sexual stimulation to work. Viagra may also take longer to work after food, particularly a high-fat meal, whereas food does not significantly affect Cialis. If one medication is ineffective despite several correctly timed attempts, speak to your doctor about adjusting the dose or trying an alternative.

Although Cialis is more expensive than Viagra, the overall cost will depend on the dose, pack size, and how frequently you have sex. Viagra may cost less per tablet, but Cialis can remain effective for up to 36 hours, so some people may need fewer tablets and will spend less overall.

For example, one Cialis pill can help you have sex several times over a weekend, whereas you may need a separate Viagra tablet every 24 hours. Viagra also only remains effective for 4 to 6 hours, so you have a short window of opportunity for sex compared to Cialis. If you have sex frequently, low-dose Cialis taken once daily may also be more cost-effective than regularly using Viagra.

If cost is a concern, generic tadalafil and sildenafil contain the same active ingredients as Cialis and Viagra, work in the same way, and are usually available at a lower price.

Cialis and Viagra are available in different dosages. The doses cannot be directly compared because tadalafil and sildenafil are different active ingredients. For example, 20mg of Cialis is not weaker than 100mg of Viagra simply because the number on the tablet is lower, it’s just that they are different medications.

Cialis vs Viagra doses are:

A higher dose may produce a stronger effect, but it can also increase the likelihood of side effects. The most suitable treatment and dose depend on your health, response and tolerability. Never increase your dose or take Cialis and Viagra together unless specifically instructed by a doctor.

No, Cialis does not make you get a harder erection than Viagra. However, individual responses can vary, so one medication may produce better erections for you than the other.

How well either treatment works can depend on the dose, correct timing, sexual stimulation, food intake, and the underlying cause of erectile dysfunction. If one treatment does not produce an erection firm enough for sex after several correctly timed attempts, speak to your doctor. They may adjust your dose or recommend an alternative.

Cialis and Viagra have broadly similar safety profiles, and neither is considered universally safer. Most side effects are mild and temporary, while serious side effects are rare with both treatments. Your individual health, other medications and response to treatment are more important when deciding which option is safer for you.

Both can cause headaches, flushing, indigestion, and nasal congestion. However, some side effects differ:

• back pain and muscle aches are more commonly associated with Cialis
• temporary vision changes, including blurred or colour-tinged vision, are more commonly associated with Viagra.
• Cialis remains active for longer, so any side effects may take longer to wear off

Both treatments can rarely cause a prolonged or painful erection, sudden changes in vision or hearing, or chest pain. Get urgent medical help if these occur. Cialis and Viagra must not be taken with nitrate medicines, and you should never take them together unless specifically instructed by a doctor.

Cialis lasts considerably longer than Viagra. A single Cialis tablet can remain effective for up to 36 hours, while Viagra generally works for around 4 hours, although its effects may last up to 6 hours in some people. This longer treatment window is why Cialis is sometimes called the “weekend pill”.

This does not mean you will have an erection throughout that time. It means Cialis may help you get an erection when you are sexually stimulated at any point during the treatment window. Viagra offers a shorter window, which some people may prefer if they only want the medication to remain active for several hours.

No, neither Viagra nor Cialis is approved specifically to treat premature ejaculation. They help you get and maintain an erection and do not reliably delay orgasm when premature ejaculation occurs without erectile dysfunction.

Treatments designed for premature ejaculation include Priligy, which contains dapoxetine, and topical anaesthetics such as EMLA cream. These work differently by helping to delay ejaculation or reduce sensitivity in your penis.

Viagra and Cialis are about as effective as each other, but which is best for you will depend on your circumstances, how long you need the treatment to be effective for, the cost, and how quickly it is effective.

Viagra may be more suitable for you if you:

• need an effective treatment that lasts 4 to 6 hours
• want a cost-effective erectile dysfunction treatment per single pill

Cialis may be more suitable for you if you:

• want a treatment that works for longer (up to 36 hours)
• want faster results (usually within 30 minutes)
• have sex frequently (more than 2 times per week) or spontaneously, as Cialis can be prescribed in a daily dose so you do not need to wait for its effects to take place

No, Cialis and Viagra must not be taken together. Both medicines are PDE-5 inhibitors, so combining them can intensify their effects on blood vessels and cause a potentially unsafe fall in blood pressure. It can also increase the likelihood and severity of other side effects.

What happens if you mix Cialis and Viagra?

Taking Cialis and Viagra together may not improve your erection, but it can expose you to a higher combined dose of PDE-5 inhibitor medication. This can increase your risk of:

• dizziness, weakness or fainting caused by low blood pressure
• headaches and facial flushing
• indigestion and nausea
• visual disturbances
• a rapid or irregular heartbeat
• a prolonged or painful erection lasting more than 4 hours, known as priapism

The risk may be greater if you take medicines that also lower blood pressure. Cialis and Viagra must never be combined with nitrates, such as glyceryl trinitrate (GTN), because this can also cause a dangerous fall in blood pressure.

Can I Take a Low Dose of Cialis and Viagra Together?

No, you should not combine even low doses of Cialis and Viagra. Cialis can remain active for up to 36 hours, so taking Viagra later may still cause the two medicines to overlap. A lower dose does not remove the risk of low blood pressure or other side effects.

If your current treatment is not working, do not add another ED medicine or increase the dose yourself. A doctor can check that you are using it correctly, review the dose, and recommend a safer alternative.

If you accidentally take Cialis and Viagra together, contact NHS 111 or a pharmacist for advice, even if you initially feel well. Call 999 for chest pain, severe dizziness, fainting, breathing difficulties or a prolonged, painful erection.

Cialis and Viagra are not the only erectile dysfunction treatments available. If you find either of these are not suitable or do not work effectively for you, Superdrug Online Doctor also offers the following Cialis and Viagra alternatives:

• Vardenafil: The active ingredient in this generic erectile dysfunction treatment is vardenafil. Like Viagra and Cialis, it is also a PDE-5 inhibitor which works by relaxing the smooth muscles in the penis to increase blood flow and cause an erection. Vardenafil is the generic version of Levitra which has been discontinued. It is a prescription-only medication but may be a more suitable option if you have experienced visual side effects with other erectile dysfunction medications because less than 2% of people who use vardenafil will get them.
• Spedra: Spedra is the fastest-acting erectile dysfunction treatment available, getting to work in as little as 15 minutes. It is also a PDE-5 inhibitor and contains the active ingredient avanafil. Spedra is effective in up to 59% of people who use it.
• Avanafil: Avanafil is the generic version of Spedra. It also works in just 15 minutes, and is available in 3 different doses; 50mg, 100mg, and 200mg.

If you feel oral tablets are not the right treatment for you, there are other treatments available such as:

• Vacuum pumps: Vaxaid vacuum pumps can make your erections last longer, often used alongside penis rings.
• Vitaros cream: Vitaros works in a similar way to oral erectile dysfunction treatments, except the treatment comes in the form of a cream you can apply. It takes 5-30 minutes to start working.