Levitra vs. Viagra vs. Cialis: Which Is Better and Will Levitra Work If Viagra Doesn’t?

How Levitra, Viagra, and Cialis Compare in Mechanism and Indication

Levitra (vardenafil), Viagra (sildenafil), and Cialis (tadalafil) are the three best-known medications in the PDE5 inhibitor class, all approved for the treatment of erectile dysfunction (ED). They share the same fundamental mechanism: each enhances the nitric-oxide–cGMP pathway responsible for relaxing smooth muscle in the penile arteries and allowing more blood to enter the erectile tissue during sexual stimulation. Because this pathway is universal across ED therapies in this class, all three drugs are considered first-line treatments, and all require sexual arousal to work.

Where they differ and where the question of whether one is “better” arises, is in their onset, duration, and side-effect profiles, as well as in how individual bodies metabolize them. Vardenafil is often described as highly selective for PDE5, which contributes to its predictable performance and tolerability. Sildenafil, the oldest and most widely recognized PDE5 inhibitor, has a similar onset window but a slightly shorter duration. Tadalafil stands apart because of its much longer half-life and extended duration of action, often lasting up to 36 hours, which has earned it the informal nickname “the weekend pill.”

These variations mean that no single drug is universally “best.” For someone who wants a relatively short, well-defined window of action, vardenafil or sildenafil may be ideal. For someone who prefers flexibility and spontaneity over several hours, tadalafil may feel more convenient. Differences in metabolism, comorbid conditions, digestive factors, and even psychological comfort with a drug’s timing can influence which medication works best for a particular individual.

When comparing Levitra, Viagra, and Cialis, the most useful perspective is not which drug is superior in absolute terms, but which one aligns most closely with a user’s expectations, health profile, and the way their body responds to PDE5 inhibition.

Comparing Onset of Action and Duration

Although Levitra, Viagra, and Cialis all work through the same biochemical pathway, their onset and duration differ in ways that meaningfully shape user preference and clinical choice. Levitra and Viagra share a similar onset of action, with most users experiencing a response within 30 to 60 minutes after taking a dose. Both medications are often recommended to be taken roughly an hour before sexual activity to allow enough time for absorption and activation. Many users report that Levitra feels slightly more predictable or consistent in onset, likely due to its high PDE5 selectivity, though this is not universal.

Cialis behaves differently. While it can also begin working around 30 minutes after ingestion, its absorption profile and exceptionally long half-life mean that its effect is less tied to a precise timing schedule. Tadalafil remains active for up to 36 hours, far longer than the 4–5 hours typical for sildenafil or vardenafil. This extended duration gives users a wide window during which sexual activity can occur without the need for careful timing, which is one reason many people prefer Cialis for its flexibility.

Levitra’s duration tends to fall in the middle range: generally 4 to 5 hours, stretching to 7 hours in some cases. This is long enough to accommodate normal variations in mood, timing, or foreplay, but short enough to avoid lingering effects long after the medication is no longer needed. Viagra’s duration is typically around four hours, making it the shortest-acting option of the three.

Since onset and duration shape how the medications fit into real life, the “best” choice often depends on timing preferences. Someone who dislikes scheduling sexual activity may gravitate toward Cialis, while someone who wants reliable but temporary support might prefer the tighter, more predictable window of Levitra or Viagra.

Side Effect Profile and Tolerability

When comparing Levitra, Viagra, and Cialis, side effects often play as important a role as timing or duration in determining which medication feels “better” for a particular user. All three are PDE5 inhibitors and therefore share a core group of common side effects: headache, facial flushing, nasal congestion, dizziness, and indigestion. These tend to be mild and short-lived, and many users adjust to them over time. Where the medications differ is in the frequency and character of certain reactions.

Viagra is well known for its occasional visual disturbances, such as a bluish tint or heightened light sensitivity. These occur because sildenafil interacts slightly with the PDE6 enzyme in retinal tissue. While usually harmless, they can be distracting, and some users prefer alternatives to avoid visual side effects.

Cialis, by contrast, has a distinct profile due to its long half-life. Some users develop muscle aches or lower-back pain, a side effect not commonly seen with sildenafil or vardenafil. This is linked to tadalafil’s mild effect on PDE11, an enzyme present in skeletal muscle. Although the aches typically resolve within a day, they can be bothersome for a minority of users.

Levitra is often regarded as having a favorable balance between efficacy and tolerability. Its high PDE5 selectivity means it produces visual side effects less frequently than sildenafil, and because it does not have the prolonged systemic exposure of tadalafil, it avoids the extended muscle aches associated with Cialis. For some men, especially those sensitive to one drug’s specific side effects, vardenafil becomes the better-tolerated option.

Ultimately, tolerability is highly individual. A medication that causes headaches or flushing for one user may produce no side effects at all for another. This variability is a major reason why clinicians sometimes encourage trying a different PDE5 inhibitor if the first option causes discomfort or seems difficult to tolerate.

When One PDE5 Inhibitor Doesn’t Work: Can Another Help?

One of the most common questions about erectile dysfunction treatments is what to do when a particular medication does not work as expected. In clinical practice, it is well established that failure with one PDE5 inhibitor does not mean failure with the entire class. Many men who do not respond adequately to sildenafil later achieve satisfactory results with vardenafil or tadalafil. The reasons for this lie in subtle but meaningful pharmacological differences, such as absorption rates, enzyme selectivity, half-life, and how each drug interacts with metabolic pathways. For example, vardenafil is known for its strong PDE5 selectivity, which may offer better potency for some users whose vascular response is less sensitive to sildenafil. Differences in tablet formulation can also matter: the way vardenafil is absorbed, how quickly it reaches peak concentration, and how consistently it maintains that concentration may lead to improved results for men who found Viagra unpredictable or insufficient. Conversely, users who need a long window of opportunity may respond better to tadalafil’s extended duration even if sildenafil failed.

Another important factor is the context of use. If Viagra was taken after a heavy meal, or without adequate sexual stimulation, or another medication interfered with its metabolism, the perceived “failure” may not reflect the drug’s true potential. Vardenafil might appear more effective simply because its absorption or timing is a better match for the user’s routine.

Psychological influences can also play a role. Anxiety, performance pressure, and unrealistic expectations often blunt a medication’s effect. Switching to a different PDE5 inhibitor sometimes improves confidence, which indirectly enhances response.

This leads to one of the key questions: Will Levitra work if Viagra doesn’t?

In many cases, the answer is yes. While no medication can guarantee effectiveness for everyone, clinical research and real-world experience consistently show that men who do not respond to sildenafil may still respond to vardenafil, thanks to differences in potency, pharmacokinetics, and tolerability.

Can You Combine Levitra With Cialis or Viagra?

Because Levitra, Viagra, and Cialis work through the same fundamental mechanism, combining them is not recommended and is almost never part of standard medical practice. Each medication enhances nitric-oxide–mediated vasodilation, lowering vascular resistance in the penile arteries and, to a lesser degree, throughout the body. When two PDE5 inhibitors are taken together, their effects overlap, increasing the risk of headache, flushing, dizziness, low blood pressure, rapid heartbeat, and fainting. These risks can occur even when the medications are taken at separate times within the same day, because systemic concentrations of the first drug may still be present when the second is introduced.

Some patients assume that doubling medications will double the results, but pharmacologically this is not how PDE5 therapy works. Once the nitric-oxide pathway is maximally supported, adding more PDE5 inhibition does not meaningfully increase erectile response; instead, it disproportionately increases side effects. The potential for dangerously low blood pressure becomes even more concerning for people taking nitrates, alpha-blockers, or blood-pressure medications.

Therefore, Levitra and Cialis should not be taken together, nor should Levitra be combined with Viagra. The only context in which a clinician might consider sequential use is when switching from one drug to another, ensuring enough time has passed for the first drug to clear. Outside of physician supervision, combining PDE5 inhibitors is unsafe and offers no therapeutic advantage.

FAQ

Is Levitra better than Viagra?

Neither drug is universally better. Levitra may be preferred by some users because of its strong PDE5 selectivity and potentially fewer visual side effects, while Viagra remains highly effective and widely used. Individual response varies, and one person may find Levitra more reliable while another prefers sildenafil.

Is Levitra better than Cialis?

Cialis offers a much longer duration (up to 36 hours), making it ideal for those who want flexibility rather than precise timing. Levitra provides a shorter, more defined window of action. The “better” choice depends on whether someone prefers spontaneity over an extended period (Cialis) or predictable effects within several hours (Levitra).

Will Levitra work if Viagra doesn’t?

Often, yes. Many men who do not respond well to sildenafil respond successfully to vardenafil due to differences in absorption, potency, and tolerability.

Can you take Levitra and Cialis together?

No. Combining PDE5 inhibitors increases side effects and cardiovascular risk without improving erectile response.