Which tablet lasts longer, and does dinner get in the way? Viagra vs Cialis is mostly a duration-and-food question. Viagra vs Levitra and Cialis vs Levitra add the third PDE5 option—vardenafil—on a similar short clock to sildenafil. This page compares the three. Buy-language for each molecule lives on the chapter pages. GenPharm XL does not sell tablets.
Updated: 2026-10-19. Reviewed against Drugs.com’s Cialis vs Viagra answer, Healthline’s class comparison, and SingleCare’s Cialis vs Viagra guide by the GenPharm XL Formulary.
Dosage ceilings and quick compare: Viagra, Cialis, Levitra
| Field | Viagra (sildenafil) | Cialis (tadalafil) | Levitra (vardenafil) |
|---|---|---|---|
| Usual as-needed ceiling | 100 mg | 20 mg | 20 mg |
| Duration often cited | ~4–5 hours | ~36 hours | ~4–5 hours (class) |
| Food | High-fat meal may delay/blunt | Little meal effect | With or without food |
| Daily low-dose option | No (ED as-needed) | Yes (often 2.5–5 mg) | No usual daily ED line |
| Also labeled for BPH | No | Yes (daily) | No |
Drugs.com’s official answer is the spine for the Viagra–Cialis pair. Both are PDE5 inhibitors that need sexual arousal. Cialis lasts around 36 hours versus about 4 to 5 hours for Viagra. Food can decrease Viagra’s effect while Cialis is food-stable. Cialis has a once-daily low-dose path and BPH use. Levitra joins the short-duration side of that map.
Viagra vs Cialis: which lasts longer?
Cialis lasts longer. That is the headline difference most readers want from viagra vs cialis.
Drugs.com puts it plainly: Cialis lasts for around 36 hours compared with only 4 to 5 hours for Viagra. SingleCare’s comparison repeats the slower-onset / longer-duration framing for tadalafil versus sildenafil. A longer window is useful when timing is uncertain. A shorter window is useful when you want the effect tied to one evening. Neither number is a stopwatch guarantee for every person.
Onset still overlaps more than marketing implies. Many people feel sildenafil within about 30–60 minutes on a light stomach. Tadalafil’s median peak is later, but the long tail is the real separator. Open cialis.html for the 20 mg vs daily fork, or viagra.html for without-prescription and 100 mg language.
Food: which meal rules matter
High-fat meals can get in Viagra’s way. Cialis is largely meal-flexible. Levitra film-coated tablets can be taken with or without food.
That is the practical meal rule from the Drugs.com pair answer and the Levitra dosage “use with food” line on the Levitra chapter. If your evenings start with a heavy dinner, tadalafil’s food story is simpler. If you can take sildenafil on a lighter stomach an hour before activity, Viagra’s food rule is manageable. Do not treat “flexible with food” as permission to skip a prescription.
Daily tadalafil vs as-needed
Daily dosing is a Cialis/tadalafil fork. Viagra and Levitra are built as as-needed tablets in the usual ED story. Choose tad for daily when that is the clinician’s plan.
SingleCare notes Cialis can be taken daily or on demand, while Viagra is on demand. Daily tadalafil strengths are low—often 2.5 mg or 5 mg—not a 20 mg every-day plan. As-needed tadalafil uses higher single doses up to 20 mg. Mixing those forks is how people invent unsafe homemade schedules. Details live on cialis.html.
Viagra vs Levitra
Viagra vs Levitra is mostly sildenafil versus vardenafil on a similar short clock.
Both need arousal. Both sit nearer a same-day window than tadalafil’s multi-opportunity span. Healthline’s class roundup groups Levitra with the other oral PDE5 options and walks dosage and side-effect differences without crowning a permanent winner. Levitra’s usual start is 10 mg with a 20 mg ceiling. Viagra’s common ED line runs 25 / 50 / 100 mg. Those dosage ceilings sit in the table above. Food flexibility favors Levitra tablets over sildenafil when dinner is heavy. Molecule depth: levitra.html and viagra.html.
Cialis vs Levitra
Cialis vs Levitra is the long window versus the short one again—tadalafil versus vardenafil.
If the job is “cover the weekend without re-timing a dose,” tadalafil’s duration story wins the comparison on paper. If the job is a single planned evening and you want a shorter-acting PDE5 with food flexibility, vardenafil competes with sildenafil more than with tadalafil. Daily BPH/ED low-dose options stay on the tadalafil side. Levitra does not replace that daily fork.
Shared stops: nitrates for all three
Do not combine any of these three with nitrates or nitric oxide donors. Never combine them with that nitrate class.
That stop is class-wide. Blood pressure can fall hard when cGMP rises from two directions. Alpha-blockers and strong CYP3A4 inhibitors add separate caution on each label. A compare page that ranks “best ED pill” without the nitrate line is incomplete.
For a suspected overdose or urgent poisoning question in the US, call Poison Help at 1-800-222-1222.
FAQ
Which is better, Viagra or Cialis?
Neither is universally better. Cialis lasts longer and is meal-flexible. Viagra is shorter-acting and more meal-sensitive. Match the job.
Does food affect Cialis the way it affects Viagra?
Usually no. High-fat meals can blunt Viagra. Cialis is largely unaffected by food in the Drugs.com comparison.
Where does Levitra fit in Viagra vs Levitra?
Levitra (vardenafil) is another short-window PDE5 option, food-flexible as tablets, with a 10 mg start and 20 mg ceiling.
Can I take Cialis every day but Viagra only as needed?
Daily low-dose is a tadalafil option. Viagra’s usual ED plan is as-needed. Do not invent a daily Viagra schedule from a Cialis blog.
Do all three block nitrates?
Yes. Nitrates are an absolute stop across sildenafil, tadalafil, and vardenafil.
Is generic the same in a compare?
Approved generics match the ingredient: sildenafil, tadalafil, or vardenafil. Appearance can differ. Buy paths stay on the molecule chapters.
Does GenPharm XL sell these tablets?
No. This is an educational compare. We do not dispense medication.
Where is the pharmacy online checklist?
On the homepage.
Next step
Pick the molecule chapter that matches your search: Viagra, Cialis, or Levitra. For class mechanism without a buy spine, open ed-pharmacology.html.