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Last updated: October 2026.
Quick answer: in the Cialis vs Viagra comparison, the main difference is time. Viagra (sildenafil) works for about 4 to 6 hours, while Cialis (tadalafil) can work for up to 36 hours. Both are prescription PDE5 inhibitors that need sexual stimulation to work. With a free pharmacy discount card, the generics cost about the same. Your doctor helps you choose.
Cialis vs Viagra is the first question most men ask when they talk to a doctor about erectile dysfunction (ED). The full picture also includes Levitra (vardenafil) and Stendra (avanafil). This guide covers Viagra vs Cialis vs Levitra on speed, duration, side effects, safety and price.
All four drugs need a prescription. ED often has a physical cause worth finding, so read what causes erectile dysfunction before your visit.
Viagra vs Cialis vs Levitra at a glance
| Viagra | Cialis | Levitra | Stendra | |
|---|---|---|---|---|
| Active ingredient | Sildenafil | Tadalafil | Vardenafil | Avanafil |
| Typical onset | About 30 to 60 minutes | About 30 minutes to 2 hours | About 30 to 60 minutes | About 15 to 30 minutes |
| Typical duration | About 4 to 6 hours | Up to 36 hours | About 4 to 6 hours | About 6 hours |
| Food effect | A heavy, fatty meal can delay it | Little effect | A heavy, fatty meal may delay it | A heavy, fatty meal may delay it |
| Daily option | No | Yes, low dose (2.5 or 5 mg) | No | No |
| Generic available | Yes | Yes | Yes (brand Levitra discontinued in the US) | Check with your pharmacy |
How do ED medications work?
ED medications work by increasing blood flow to the penis when you are sexually aroused. All four belong to a class called PDE5 inhibitors. They block an enzyme that relaxes blood vessels for a shorter time than normal.
They do not cause an erection on their own. You still need sexual stimulation. They also do not raise sex drive or treat the cause of ED. Because the mechanism is shared, Cialis vs Viagra differences come down mainly to timing, food and side effects.
Cialis vs Viagra: what is the difference?
The key difference in Cialis vs Viagra is how long each one stays active. Viagra lasts about 4 to 6 hours. Cialis can last up to 36 hours, which is why some people call it “the weekend pill.”
Other differences in the Cialis vs Viagra choice:
- Food: a heavy, fatty meal can delay Viagra. Cialis is less affected by food.
- Daily use: Cialis comes as a low daily dose (2.5 or 5 mg). Viagra is taken only before sex.
- Urinary symptoms: Cialis is also approved for symptoms of an enlarged prostate (BPH). Viagra is not.
- Side effects: back and muscle pain are more common with Cialis. A blue tinge to vision is mainly seen with Viagra.
Neither drug is clearly stronger for every man. Response varies from person to person.
Which ED medication works fastest?
Avanafil (Stendra) can work the fastest, in about 15 to 30 minutes for some men. Sildenafil and vardenafil usually take about 30 to 60 minutes. Tadalafil takes about 30 minutes to 2 hours.
For speed in a Cialis vs Viagra matchup, Viagra often starts a little sooner, unless it follows a heavy meal.
Which ED medication lasts longest?
Tadalafil (Cialis) lasts the longest, up to 36 hours. Avanafil lasts about 6 hours, and sildenafil and vardenafil about 4 to 6 hours.
Duration means the window when an erection is easier to get with stimulation. It does not mean an erection that lasts for hours. An erection lasting more than 4 hours is a medical emergency. This window is the biggest practical gap in Cialis vs Viagra.
Cialis vs Viagra price: which costs less?
On Cialis vs Viagra price, the generics cost about the same with a discount card. According to GoodRx data published in April and May 2026, 30 tablets of generic sildenafil or generic tadalafil run about $12 at many US pharmacies with a free pharmacy discount card. Brand names cost far more.
| Drug (30 tablets) | Typical retail price | With a discount card, from |
|---|---|---|
| Generic sildenafil (25-100 mg) | About $610-$790 | About $12 |
| Generic tadalafil (5 mg) | About $147 | About $12 |
| Brand Cialis (5 mg) | About $444 | About $293 |
| Brand Viagra (25-100 mg) | About $2,960-$3,140 | About $754 |
The Cialis vs Viagra price gap mostly disappears when you buy generic. Prices change and vary by pharmacy, dose and location. Ways to pay less:
- Ask your doctor to prescribe the generic.
- Compare prices at several pharmacies.
- Count how many tablets you actually need each month.
- Check whether your insurance covers any of the cost.
Side effects compared
The most common side effects are similar for all four drugs: headache, flushing, nasal congestion and indigestion. They are usually mild and fade as the drug wears off.
| Side effect | Sildenafil | Tadalafil | Vardenafil | Avanafil |
|---|---|---|---|---|
| Headache, flushing | Common | Common | Common | Common |
| Nasal congestion, indigestion | Common | Common | Common | Common |
| Back and muscle pain | Less common | More common | Less common | Less common |
| Blue tinge to vision | Mainly this drug | Rare | Rare | Rare |
| Sudden vision or hearing loss | Rare, seek care | Rare, seek care | Rare, seek care | Rare, seek care |
| Erection over 4 hours (priapism) | Rare, emergency | Rare, emergency | Rare, emergency | Rare, emergency |
If one drug gives you side effects, your doctor may suggest another. The Cialis vs Viagra side-effect profiles differ enough that switching sometimes helps.
Who should not take ED medications?
Men who take nitrates must never take any ED medication. The combination can cause a dangerous drop in blood pressure.
- Nitrates: nitroglycerin and isosorbide, often used for chest pain.
- Poppers: recreational amyl nitrite is also a nitrate.
- Riociguat: a drug for some lung blood-pressure conditions.
Use caution with alpha-blockers such as tamsulosin or doxazosin, and with heavy alcohol, which can also lower blood pressure. Tell your doctor about every medicine and supplement you take. These rules apply on both sides of Cialis vs Viagra and to every PDE5 inhibitor.
Which ED medication is right for you?
The right choice depends on your situation, your health and your doctor’s advice. These are common patterns, not recommendations:
- Planned sex and lowest cost: generic sildenafil is often a starting point.
- Spontaneity or weekends: tadalafil gives a longer window.
- ED plus urinary BPH symptoms: daily tadalafil may cover both.
- Fastest onset: avanafil can work in about 15 to 30 minutes.
- Side effects on one drug: your doctor may try another.
Many men settle the Cialis vs Viagra question by trying one, then the other, under a doctor’s guidance.
What about supplements instead of ED medications?
Supplements are not a substitute for ED medications. L-citrulline, an amino acid linked to nitric oxide production, has only small trials, and only in mild ED. Products sold as “natural Viagra” are sometimes tainted with hidden drug ingredients, according to FDA warnings. If you want to try L-citrulline, choose a plain single-ingredient product and tell your doctor. One option is an unflavored L-citrulline powder, though it has no proven effect on moderate or severe ED.
- No Malate, Just Pure Base Powder
- 3 Grams of L-Citrulline Powder Per Serving (200 Servings)
- 600 Grams of L-Citrulline Powder Per Bottle
We review the evidence in best L-citrulline supplements and best ED supplements for 2026.
What if ED medications don’t work?
If ED medications don’t work, other options exist, so talk to your doctor. A first try often fails because of timing, a heavy meal or too little stimulation.
- Dose adjustment: your doctor may change the dose or switch drugs.
- Testosterone check: low testosterone can blunt the response. See low testosterone symptoms in men over 40.
- Vacuum pumps: a device that draws blood into the penis.
- Injections: medicine injected into the penis, prescribed by a urologist.
- Therapy: stress, anxiety and relationship issues play a role. Read psychological ED: mental or physical?
Lifestyle steps and pelvic floor exercises for ED can support treatment.
When should you see a doctor?
See a doctor as soon as ED becomes a regular problem, before you start any medication. ED can be an early sign of heart disease, because the penile arteries are small and may show damage first. Learn more in erectile dysfunction and heart disease.
Get emergency care for:
- An erection that lasts more than 4 hours.
- Sudden loss of vision or hearing.
- Chest pain, dizziness or fainting during or after sex.
Cialis vs Viagra FAQ
Is Cialis or Viagra better?
Neither is better for every man. In Cialis vs Viagra, Cialis lasts up to 36 hours and Viagra about 4 to 6 hours. A doctor helps you choose based on your health, habits and side effects.
Which is cheaper, Cialis or Viagra?
On Cialis vs Viagra price, generic tadalafil and generic sildenafil both cost about $12 for 30 tablets with a free pharmacy discount card at many US pharmacies, per GoodRx data from April and May 2026. Brand names cost much more.
How long does Cialis last compared with Viagra?
In Cialis vs Viagra, Cialis (tadalafil) can work for up to 36 hours. Viagra (sildenafil) usually works for about 4 to 6 hours. Both need sexual stimulation to produce an erection.
Which ED pill works fastest?
Avanafil (Stendra) can work in about 15 to 30 minutes. Sildenafil and vardenafil take about 30 to 60 minutes, and tadalafil about 30 minutes to 2 hours.
Is Levitra still available in the US?
Brand Levitra has been discontinued in the US, but generic vardenafil is available with a prescription. It works for about 4 to 6 hours, similar to sildenafil.
Can I take ED medication with blood pressure pills?
Ask your doctor first. ED drugs must never be combined with nitrates or riociguat. Caution is needed with alpha-blockers such as tamsulosin or doxazosin, which also lower blood pressure.
Can I drink alcohol with Viagra or Cialis?
A small amount is usually not a problem, but heavy alcohol can lower blood pressure and make erections harder. Ask your doctor about alcohol with your specific medication.
Does daily Cialis help with urinary symptoms?
Yes. Low-dose daily tadalafil is approved for both ED and urinary symptoms of an enlarged prostate (BPH). This is one practical edge in Cialis vs Viagra for older men.
Can supplements replace Viagra or Cialis?
No. L-citrulline has only small trials in mild ED. FDA warnings note that some products sold as natural Viagra contain hidden drug ingredients, which can be dangerous.
What should I do if an erection lasts over 4 hours?
Get emergency medical care right away. An erection lasting more than 4 hours, called priapism, can permanently damage the penis if it is not treated quickly.
Bottom line
The Cialis vs Viagra decision mostly comes down to timing. Viagra works for about 4 to 6 hours, Cialis for up to 36 hours, and generic versions of both can cost about $12 for 30 tablets with a discount card. Levitra and Stendra are alternatives. Talk to a doctor, who can check your heart health and choose a safe option.
References
- U.S. Food and Drug Administration: Drugs.
- MedlinePlus: Erectile Dysfunction.
- NIDDK: Erectile Dysfunction.
- American Urological Association: Guidelines.
- GoodRx (price data, April and May 2026).
This article is for information only and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease.