Last Updated on May 30, 2020 by Dr. Philip Schein MD

Many medications belonging to the group of PDE5 inhibitors have relatively short-acting effect. They usually work for up to 6 hours. In predominant part of situations, this would be enough, but sometimes males can complain of poor spontaneity. Luckily enough, there is a great option of them which is called Cialis. Its branded version is pretty expensive, but there are many licensed and certified generics featuring tadalafil (the key component of Cialis) on the pharmaceutical market. So tadalafil stays in the system much longer, providing long-running effect. How long does it stay in the human body?

tadalafil mechanism of action

Tadalafil – Mechanism of Action

Erectile dysfunction is an annoying problem. Struggling with poor erections can induce nervousness, decreased confidence and relationship worsening. But oral treatment with tadalafil provides perfect results. The principle of action is basically the same as that of the preeminent azure pill (we mean Viagra), but this medicine contains another active component. This is a PDE5 inhibitor which suppresses natural substance which interferes with erection (phosphodiesterase type 5), thereby tadalafil boosts blood flow and increases penile hardness. Its manufacturers have succeeded in creation of more potent substance that can provide the same effect as Viagra with lowered dosage of the principal constituent.

how long does cialis generic stay in the body

Tadalafil – Time of Staying in the Organism

Most of phosphodiesterase type 5 inhibitors stay in the human organism for up to 6 hours. This concerns Viagra, for example (however, some studies have been shown that it might be effective for up to 12 hours in many patients). Anyway, its effect begins to abruptly or gradually decrease once 5-6 hours have passed. Tadalafil is definitely a winner in this regard, it provides useful effect for up to 36 hours (up to 1.5 days!). Such a long action is associated with its half-life. According to a study by Robert M Coward and Culley C Carson (Therapeutics and Clinical Risk Management, 2008), the half-life of this pharmaceutical substance is 17.5 hours in normal healthy males and 21.6 hours in the elderly.

Note that tadalafil is a symptomatic and temporary treatment, not a cure, for erectile dysfunction. Many gentlemen use it for an extended period (it doesn’t cause tolerability and addiction, which is a pretty good side of it). Durable therapy doesn’t lead to a loss of tolerance; you may not worry about it. Numerous clinical studies have shown that long-term treatment is unproblematic if the instructions for administration are carefully followed.

You might be interested in: Is 20 mg Cialis Equal to 100 mg Viagra?


Averagely 5-10 per cent of users experience undesirable reactions like headache, backache, stomach upset, memory issues (forgetfulness), and flu-like symptoms. If used improperly (in excessive dosages), adverse events’ risk increases.

According to a study performed by clinicians at University of Köln, Germany in 2002, pharmacokinetics (drug absorption and delivery in the body) of PDE5 inhibitors (like sildenafil and tadalafil) may become less predictable when a patient takes grapefruit juice. This associated with the fact that substances in grapefruit oppress activity of cytochrome P450 3A4 (abbreviated CYP3A4) enzyme which located primarily in intestine liver and is responsible for removal of toxins and some pharmaceutical agents from the organism. Hence, don’t eat grapefruit and don’t drink grapefruit-based juices and smoothies when using tadalafil. This especially applies to Cialis as it has long half-life.

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I’m an Oncologist and Hematology Specialist primary located in Bryn Mawr, Pennsylvania. I have over 55 years of experience in the medical field and more than 20 years of practice. I’m skilled at the treatment & diagnosis of a large array of ailments & diseases in adults.

Board certifications

  • American Board of Internal Medicine Certification in Internal Medicine
  • American Board of Hematology Certification in Hematology
  • American Board of Medical Oncology Certification in Medical Oncology