Cialis vs. Levitra vs. Viagra: How Each Stacks Up

Medically reviewed by Alan Carter, PharmD on July 29, 2016 — Written by Ann Pietrangelo on October 1, 2014

Three of a kind?

Cialis, Levitra, and Viagra are oral medications used to treat erectile dysfunction (ED). You may also know them by their generic names, tadalafil (Cialis), vardenafil (Levitra), and sildenafil (Viagra).

About 30 million men occasionally have a problem with getting or keeping an erection, according to the Urology Care Foundation. When ED becomes a problem, many men turn to oral ED medications. These drugs often help. Cialis, Levitra, and Viagra each work in similar ways. But there are also some differences, such as when you take them, how long they work, and what their side effects are.

Cialis, Levitra, and Viagra

Drug features

     Cialis, Levitra, and Viagra are all in a class of drugs called PDE-5 inhibitors. These drugs work by blocking an enzyme called phosphodiesterase type 5. They also boost a chemical in your body called nitric oxide. This action encourages the muscles in your penis to relax. Relaxed muscles allow blood to flow freely so that when you’re aroused, you can get an erection. It also helps you maintain the erection long enough to have sex.

Levitra and Viagra stay in your bloodstream for about four to six hours. Cialis remains in your bloodstream for 17 to 18 hours or longer. The length of time a drug stays in your system may be important if you’re taking other medications.

Here are more basics on each of these drugs:

Brand name Cialis Levitra Viagra
What is the generic drug? tadalafil vardenafil sildenafil
Is a generic version available? no no no
What does it treat? erectile dysfunction erectile dysfunction erectile dysfunction
What form does it come in? oral tablet oral tablet oral tablet
What strengths does it come in? 2.5 mg, 5 mg, 10 mg, 20 mg 2.5 mg, 5 mg, 10 mg, 20 mg 25 mg, 50 mg, 100 mg
When do I take it? 30-60 mins before sex or once daily 30-60 mins before sex 30-60 mins before sex
How long does it work? up to 36 hours up to 8 hours 4-5 hours
Should I take it with food? take it with or without food take it with or without food take it with or without food
How do I store it? store at room temperature close to 77°F (25°C) store at room temperature close to 77°F (25°C) store at room temperature close to 77°F (25°C)
Does this drug have potential for misuse? yes* yes* yes*

* This drug is commonly misused without a prescription.
Be sure to take this drug exactly as your doctor tells you to. If you have questions or concerns, talk with your doctor.

Cost and availability–Cost, availability, and insurance

Cialis, Levitra, and Viagra are usually stocked at most pharmacies. All three of these drugs cost about the same amount. In general, most health insurance companies won’t cover their costs. But if you have certain medical conditions, your health plan may pay for the drug with prior authorization.

Side effects

The side effects of these medications are similar. Most men have only mild side effects.

The chart below compares the side effects of these drugs.

Side effect Cialis Levitra Viagra
stuffy or runny nose x x x
headache x x x
upset stomach x x x
changes in vision x x
flushing x x
back pain x
muscle aches x
priapism (an erection that won’t go away) x x x
sudden cardiac arrest and death x x x

Tell your doctor if you have any side effects that linger and don’t go away on their own. If you have an erection that lasts longer than four hours, call your doctor right away.

Keep reading: More info on the 7 common side effects of ED drugs »