How Long Does Tadalafil (Cialis) Last?
Tadalafil can work for up to 36 hours—that's why it's called "the weekend pill." Take it Friday evening and it may still be working Sunday morning. Here's everything you need to know about timing, dosing options, and getting the best results.
Quick Answer
30 min
can start working
2 hr
peak concentration
36 hr
duration of effect
17.5 hr
half-life
Why Tadalafil Lasts So Much Longer
Tadalafil's extended duration is its defining feature. While sildenafil (Viagra) lasts 4-6 hours, tadalafil keeps working for up to 36 hours. The difference comes down to pharmacokinetics—how your body processes the drug.
Half-Life Comparison
4 hours
Sildenafil half-life
Clears quickly, effects fade by 4-6 hours
17.5 hours
Tadalafil half-life
Stays active much longer, up to 36 hours
This long half-life means tadalafil maintains effective blood levels for much longer. Even 36 hours after taking it, you still have enough medication in your system to respond to sexual stimulation.
The Tadalafil Timeline
Here's what happens after you take a dose of tadalafil (10mg or 20mg as-needed):
16 min
fastest
First responders
Some men report effects as early as 16 minutes—faster than many expect.
30 min
typical
Most men feel effects
Studies show 52% of men can achieve successful intercourse within 30 minutes of taking tadalafil.
2 hr
peak
Maximum concentration
Peak blood levels are reached about 2 hours after dosing (can range from 30 minutes to 6 hours).
17.5 hr
half-life
Half the drug remains
At this point, half the medication has been cleared—but you still have effective levels in your system.
36 hr
duration
Still effective for most men
Many men can still achieve erections with sexual stimulation up to 36 hours after dosing.
48-72 hr
some men
Extended effects possible
Some men report residual effects for up to 48-72 hours, though this varies significantly.
96 hr
cleared
Fully cleared from system
After about 4 days, tadalafil has virtually disappeared from your bloodstream.
Two Ways to Take Tadalafil
Unlike sildenafil, tadalafil offers two distinct dosing strategies. Your choice depends on your lifestyle and how often you're sexually active:
As-Needed (10mg or 20mg)
- ✓ When: Take 30 minutes to 2 hours before anticipated sexual activity
- ✓ Duration: Lasts up to 36 hours per dose
- ✓ Max frequency: No more than once every 24 hours
- ✓ Best for: Men who are sexually active 1-2 times per week or less
Daily (2.5mg or 5mg)
- ✓ When: Take at the same time every day, regardless of sexual activity
- ✓ Duration: Continuous—always ready
- ✓ Onset: Takes 3-5 days to reach steady levels
- ✓ Best for: Men who are sexually active more than twice per week, or want full spontaneity
Study Finding: Men Prefer Tadalafil
In a 2003 crossover study where men tried both sildenafil and tadalafil, 66.3% preferred tadalafil compared to 33.7% for sildenafil. In another study, 79% of female partners also preferred tadalafil because of the "more relaxed approach" to intimacy it allows.
What Affects How Long Tadalafil Lasts?
Age
Men 65 and older tend to have higher blood levels of tadalafil and may experience effects for longer. This is because metabolism slows with age. Older men often start with lower doses.
Food
Unlike sildenafil, tadalafil can be taken with or without food. Heavy, high-fat meals may delay absorption slightly but don't significantly reduce effectiveness. This is a major advantage—you don't have to time it around meals.
Alcohol
Moderate alcohol (1-2 drinks) is generally fine with tadalafil. However, excessive alcohol can cause blood pressure drops (both tadalafil and alcohol dilate blood vessels) and interfere with your ability to get an erection. Since tadalafil stays in your system for 36+ hours, this applies for a longer window.
Grapefruit
Grapefruit and grapefruit juice can interfere with how your body metabolizes tadalafil, potentially increasing blood levels and side effects. The effect can last up to 3 days, so consider avoiding grapefruit entirely while using tadalafil.
Liver or Kidney Problems
These conditions slow down drug metabolism, so tadalafil may last longer and have stronger effects. Lower doses are typically recommended.
Tadalafil vs Other ED Medications: Duration
| Medication | Duration | Half-Life | Daily Option? |
|---|---|---|---|
| Sildenafil (Viagra) | 4-6 hours | ~4 hours | No |
| Vardenafil (Levitra) | 4-5 hours | ~5 hours | No |
| Avanafil (Stendra) | ~6 hours | ~5 hours | No |
| Tadalafil (Cialis) | Up to 36 hours | 17.5 hours | Yes |
Which Dosing Strategy Is Right for You?
Choose As-Needed (10mg/20mg) If:
- • You're sexually active 1-2 times per week or less
- • You don't want to take daily medication
- • You're okay with some planning (though 36 hours is very flexible)
- • Cost is a concern (fewer pills = lower cost)
Choose Daily (2.5mg/5mg) If:
- • You're sexually active more than twice per week
- • You want complete spontaneity—no planning at all
- • You also have BPH (benign prostatic hyperplasia)—daily tadalafil treats both
- • You experience side effects with higher doses (daily low-dose may reduce side effects)
Important Safety Notes
Remember
Tadalafil still requires sexual stimulation to work. A 36-hour window doesn't mean a 36-hour erection—it means you can respond to arousal during that entire period.
Seek immediate medical help if:
- ⚠ Erection lasting more than 4 hours (priapism): This is a medical emergency that can cause permanent damage.
- ⚠ Sudden vision or hearing loss
- ⚠ Chest pain during or after sex
Drug Interactions
Never take tadalafil with nitrates (nitroglycerin, isosorbide) or "poppers"—the combination can cause dangerous blood pressure drops. Be cautious with alpha-blockers. Always tell your doctor about all medications you take.
Ready to Try Tadalafil?
Get a prescription online from licensed providers. Choose between as-needed or daily dosing based on your lifestyle.
The Bottom Line
Tadalafil's 36-hour duration makes it the most flexible ED medication available. Take it Friday evening and you're covered through Sunday—no precise timing required. The daily low-dose option takes spontaneity even further, keeping you ready at all times. Whether you choose as-needed or daily dosing depends on how frequently you're sexually active and how much you value spontaneity over cost.