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Last updated: Mar 31, 2021
5 min read

What is Cialis? How long does it last?

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Medically Reviewed by Felix Gussone, MD

Written by Cale Li, MD

Disclaimer

If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

Cialis is the brand name of a drug called tadalafil (see Important Safety Information), a popular medication used to treat erectile dysfunction (ED). Cialis belongs to a group of drugs called PDE5 inhibitors, which also include sildenafil (Viagra; see Important Safety Information) and vardenafil (Levitra). PDE5 inhibitors enhance your body’s natural arousal response by increasing blood flow to the penis, giving you harder erections. Compared with other ED drugs, Cialis lasts longer, working for up to 36 hours. But that doesn’t mean a continuous erection for 36 hours. It means that the medicine enhances your ability to get hard over the course of 36 hours.

As a treatment for ED, you can take tadalafil one of two ways (Rew, 2016):

  • As needed: dose taken as directed, at least 30 minutes before sexual activity
  • Every day: a lower dose taken at the same time each day without regard to when you have sex

Some people prefer to take Cialis only when they plan to have sex. Alternatively, you can ask your healthcare provider about a daily option to keep your plans a little bit more spontaneous. 

Whether you and your healthcare provider opt for the smaller daily dose or the larger as-needed dose, tadalafil’s effects start around 30 minutes after you take it. Cialis also lasts longer than other PDE5 inhibitors. People who use Cialis report that they can get harder erections for up to a day and a half after their dose (Smith-Harrison, 2016). 

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Can I take 40 mg? How much Cialis is too much?

The maximum daily dose of Cialis is 20 mg when taken as-needed. Taking more than that, like doubling the dose to 40 mg, or combining Cialis with other PDE5 inhibitors like Viagra (sildenafil) is not recommended and will likely increase the risk for side effects. 

Side effects and potential risks of Cialis

The most common side effects are headaches, facial flushing, back pain, muscle ache, and changes in vision (FDA, 2011). Since Cialis is long-lasting, its side effects can last longer as well. In some people, they can linger for more than 12 hours compared with less than four hours for people taking sildenafil (Taylor, 2009).

What if Cialis isn’t working for me?

Maybe Cialis isn’t working as you hoped it would. That can happen. Luckily there are some troubleshooting steps you can take to make sure you get the most out of your meds. First of all, make sure you’re timing it right. If you’re taking the drug as-needed,  try to make sure you’re taking it at least 30 minutes before sex (Rew, 2016). If you’re taking tadalafil once daily, make sure not to skip any doses and try to take it at the same time every day. Setting a reminder on your smartphone is a great way to time it properly. 

While drugs like Cialis are pretty effective, they aren’t magic and they won’t give you out-of-the-blue boners. You need to get aroused for them to work. Arousal is a complex creature: it can be physical, some light touching or foreplay to set the mood; it can also be mental, getting excited over roleplay, erotic movies, or introducing something kinkier into the bedroom. Comfort also plays a role. Anxiety is a major boner-killer, so spending time getting to know your partner better may be the best aphrodisiac of all. 

If you think the timing isn’t the issue, ask your healthcare provider about changing the way you’re taking Cialis: in one study, men who had only a partial response to as-needed PDE5 inhibitors switched over to the once-daily tadalafil and had better erectile function (Kim, 2013). Talk to your healthcare provider about any changes in Cialis effectiveness as well as other medications you may be taking; some drugs can affect how well tadalafil works. 

Other treatments for ED

If you’ve tried troubleshooting the problem and you’re still not happy with tadalafil, there are plenty of options out there.  

Lifestyle Changes

Cigarette smoking is associated with higher rates of erectile dysfunction. Research studies show that men who quit smoking have improved erectile function (Kovac, 2015). 

Diet and exercise also play a role, particularly moderate-to-intense aerobic exercise which can help improve erections (Silva, 2017). In one study, young men who increased their fruit and vegetable intake, decreased alcoholic beverage consumption, and smoked less had better erectile function (Mykoniatis, 2018). 

Treating underlying health problems

Many common health conditions can lead to erectile dysfunction, including diabetes, cardiovascular disease, low testosterone, obesity, and depression (Rew, 2016). Untreated, these conditions can interfere with your body’s ability to sustain an erection, even when using medications like tadalafil. 

Additional treatment options 

If tadalafil and other PDE5 inhibitors are not working for you, your healthcare provider may suggest other treatment options including (Pastuszak, 2014):

  • Testosterone therapy for erectile dysfunction that’s caused by low levels of testosterone
  • Injections into the penis: Alprostadil and other medications directly stimulate the penis to get hard 
  • Vacuum restriction devices: Can keep the penis hard for up to 30 minutes

Let’s recap: Cialis is an effective drug for treating erectile dysfunction. One advantage of Cialis is that it stays in your body longer than other PDE5 inhibitors, allowing for more spontaneity in your sex life. 

References

  1. Food and Drug Administration (FDA). (2011). Cialis (tadalafil) tablets. FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/021368s20s21lbl.pdf 
  2. Kim, E. D., Seftel, A. D., Goldfischer, E. R., Ni, X., & Burns, P. R. (2014). A return to normal erectile function with tadalafil once daily after an incomplete response to as-needed PDE5 inhibitor therapy. The Journal of Sexual Medicine, 11(3), 820–830. doi: 10.1111/jsm.12253. Retrieved from https://pubmed.ncbi.nlm.nih.gov/23841532/ 
  3. Kovac, J. R., Labbate, C., Ramasamy, R., Tang, D., & Lipshultz, L. I. (2015). Effects of cigarette smoking on erectile dysfunction. Andrologia, 47(10), 1087–1092. doi: 10.1111/and.12393. Retrieved from https://pubmed.ncbi.nlm.nih.gov/25557907/ 
  4. Mykoniatis, I., Grammatikopoulou, M. G., Bouras, E., Karampasi, E., Tsionga, A., Kogias, A., Vakalopoulos, I., Haidich, A. B., & Chourdakis, M. (2018). Sexual Dysfunction Among Young Men: Overview of Dietary Components Associated With Erectile Dysfunction. The Journal of Sexual Medicine, 15(2), 176–182. doi: 10.1016/j.jsxm.2017.12.008. Retrieved from https://pubmed.ncbi.nlm.nih.gov/29325831/ 
  5. Pastuszak A. W. (2014). Current Diagnosis and Management of Erectile Dysfunction. Current Sexual Health Reports, 6(3), 164–176. doi: 10.1007/s11930-014-0023-9. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4394737/ 
  6. Pendharkar, S., Mattoo, S. K., & Grover, S. (2016). Sexual dysfunctions in alcohol-dependent men: A study from north India. The Indian Journal of Medical Research, 144(3), 393–399. doi: 10.4103/0971-5916.198681. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5320845/ 
  7. Rew, K. T., & Heidelbaugh, J. J. (2016). Erectile Dysfunction. American Family Physician, 94(10), 820–827. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27929275/ 
  8. Silva, A. B., Sousa, N., Azevedo, L. F., & Martins, C. (2017). Physical activity and exercise for erectile dysfunction: systematic review and meta-analysis. British Journal of Sports Medicine, 51(19), 1419–1424. doi: 10.1136/bjsports-2016-096418. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27707739/ 
  9. Smith-Harrison, L. I., Patel, A., & Smith, R. P. (2016). The devil is in the details: an analysis of the subtleties between phosphodiesterase inhibitors for erectile dysfunction. Translational Andrology and Urology, 5(2), 181–186. doi: 10.21037/tau.2016.03.01. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4837309/ 
  10. Taylor, J., Baldo, O. B., Storey, A., Cartledge, J., & Eardley, I. (2009). Differences in side-effect duration and related bother levels between phosphodiesterase type 5 inhibitors. British Journal of Urology International, 103(10), 1392–1395. doi: 10.1111/j.1464-410X.2008.08328.x. Retrieved from https://pubmed.ncbi.nlm.nih.gov/19154494/