Cialis (tadalafil) typically stays in your system for about 3 to 5 days after taking a single dose. Its half-life is approximately 17.5 hours, meaning it takes that long for the concentration of the drug in your bloodstream to reduce by half. The effects last up to 36 hours, but the medication can be detected in the body for several days due to its long half-life and metabolism process.

Key Details:

• Cialis begins working within 30 minutes to 2 hours after ingestion.
• Effects can last up to 36 hours, which is why it is called the "weekend pill."
• The drug itself can remain in the body and be detectable for about 3 to 5 days.
• Factors like age, metabolism, liver and kidney function, and other medications can influence how long Cialis stays in your system.
• It may take roughly 5 half-lives (about 3.6 days) to clear the drug from your body completely.

In summary, while the active effects of Cialis last around 36 hours, the medication can stay in your system for up to 5 days before being fully eliminated.