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Can I Take 40 mg of Cialis (Tadalafil)?

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD

Written by Sian Ferguson

Published 05/22/2021

Updated 01/16/2024

Cialis® is an FDA-approved erectile dysfunction (ED) treatment also known by its generic name, tadalafil. If you’re currently using Cialis and it’s not having the desired effect, you might be wondering, Can I take 40 mg of Cialis?

In short, no. While it may be tempting to take more Cialis than prescribed, it’s not safe.

As a general rule, you should only use prescription drugs as prescribed. Increasing your Cialis dosage comes with the chance it’ll elevate your risk of experiencing side effects — which can be very dangerous.  

We recommend sticking to your prescribed dosage. After all, ending up in the hospital with dangerously low blood pressure is the very definition of a mood-killer, right?

Fortunately, if your Cialis dosage isn’t working, there are a number of (safe) steps you can take to address it. Let’s look at the safety risks of using 40 mg (milligrams) of Cialis and explore alternative treatments for erectile dysfunction.

No, it’s not safe to take 40 mg of tadalafil unless your doctor specifically told you to do so. A Cialis overdose can lead to severe side effects, and a 40-mg dose won’t necessarily improve your erectile function more than your prescribed dose. 

To understand why, let’s go over the basics of tadalafil.

Cialis is a unique erectile dysfunction treatment because there are two ways to use it. You can take it on an as-needed basis at least 30 minutes to two hours before sexual activity or as a once-a-day pill.

Often called the “weekend pill,” Cialis lasts approximately 36 hours — making it a little easier to have spontaneous sex.

Tadalafil can also be used to treat benign prostatic hyperplasia (BPH), a condition characterized by an enlarged prostate gland. It’s sometimes prescribed for pulmonary arterial hypertension (PAH), a type of high blood pressure that affects the arteries in the lungs. This medication may even help treat ureteral stones.

Your prescribed dosage will depend on how you use Cialis and what you use it for:

  • If you’re using Cialis for erectile dysfunction on an as-needed basis, the starting dose is usually 10 mg. This can be increased to 20 mg or decreased to 5 mg.

  • If you’re taking a daily dose of Cialis for ED, the standard dosage is 2.5 mg, although it can be increased to 5 mg. 

  • If you’re using Cialis for BPH, the recommended dose is 5 mg a day.

Currently, Cialis is available in 2.5, 5, 10 and 20-mg tablets.

As noted, you won’t necessarily get more out of a 40-mg Cialis dosage than what’s been prescribed to you for the treatment of erectile dysfunction.

To explain why, let’s quickly go over how erections work. When you’re aroused, your brain sends signals to your body to increase blood flow to your penis. This leads to an erection, which is when the fun begins!

But if you’re not turned on, or if there’s an issue with your blood vessels that prevents them from dilating properly, it’ll be harder to get an erection — pun not intended. 

Drugs like Cialis are known as phosphodiesterase type 5 (PDE5) inhibitors. PDE5 inhibitors work by blocking phosphodiesterase 5 enzymes, which can interfere with blood vessel dilation. This helps blood flow to the penile tissues. 

It’s important to remember that erectile dysfunction drugs don’t automatically give you an erection. Whether or not Cialis works depends on the cause of your erectile dysfunction.

Many factors can contribute to ED, including using drugs (prescription and illicit), stress, anxiety, poor diet, blood flow issues and hormone imbalances. 

So, for example, if you’re struggling to get an erection because you’re too anxious to feel turned on, Cialis might not help — no matter what dosage you take. 

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Cialis is generally safe for most people, but there are some potential side effects you should be aware of. 

Common side effects of tadalafil include:

  • Headache

  • Indigestion

  • Flushing

  • Muscle pain

  • Pain in limbs 

  • Back pain

  • Nasal congestion

Much less common (but way more serious) side effects can include:

  • Allergic reaction 

  • Sudden drop in blood pressure (hypotension) if taken with certain other medications, which is dangerous because bodily tissues may not get all the oxygen they need to function

  • Hearing loss or loss of vision

  • Priapism, a painful condition where an erection lasts over four hours

If you have any of these side effects, seek medical attention immediately. 

Taking 40 mg of Cialis is even riskier if you mix it with certain other drugs, foods or supplements. Common tadalafil drug interactions include:

  • Other PDE5 inhibitors

  • Nitrates like nitroglycerin

  • Grapefruit, which can affect how your liver processes certain drugs

  • Some blood pressure medications, including alpha-blockers 

  • Certain antifungal and antibiotic medications, like ketoconazole and clarithromycin

While you should never mix these drugs with tadalafil without discussing it first with a healthcare provider, it’s extra dangerous if you mix them with a higher dose of tadalafil. 

The side effects of Cialis can occur at any dosage — but higher dosages can equal a higher risk for drug interactions.  

Choose your chew

Now you know why taking too much Cialis can be dangerous and ineffective — but what can you do if your Cialis dosage isn’t working? Here are a few strategies to consider. 

Make Sure You’re Using Cialis Properly

Before anything else, it’s vital to ensure you’re using your medication properly. This will help you get the maximum effect from Cialis.

As mentioned, Cialis can either be taken as needed before having sex or on a daily basis. If you’re taking it as needed, remember to take it at least 30 minutes to two hours before sex, to give it time to kick in. If you’re taking a daily dose, remember it typically works for 36 hours. If 36 hours have passed since you took your last dose, you might find it more difficult to get an erection.

Keep forgetting to take your meds? Setting an alarm on your phone will alert you when to take it each day, plus you’ll know exactly how long it’s been since your last dose.

Consider Psychological Factors That Can Cause ED

Mental health can directly affect physical health. And just as anxiety can cause your stomach to tense up, psychological factors can contribute to ED.

Issues like anxiety, depression and sexual performance anxiety can affect erectile function. This can have a circular effect: Erectile dysfunction can, in turn, cause stress and anxiety as well as relationship issues. 

In-person or online therapy can help you get ahead of psychological ED. Not only can therapy help you get to the root of your ED, but it can also teach you a range of skills so you can thrive in many areas of your life. Worth the investment, right?

Be Aware of Pre-Existing Health Conditions That Can Cause ED

Dealing with the root cause of ED can be key to improving erectile function. Erectile dysfunction can be caused by pre-existing medical conditions, from cardiovascular disease to autoimmune conditions.  

For instance, ED could be a symptom or result of:

  • Type 2 diabetes

  • Heart disease or blood vessel disease

  • Hypertension (high blood pressure)

  • Chronic kidney disease 

  • Multiple sclerosis 

  • Atherosclerosis (clogged arteries)

  • Peyronie’s disease 

  • Injury from prostate cancer treatment 

  • Surgery for bladder cancer 

  • Injury to the erectile tissues, genitals or pelvis

  • Neurological problems, such as injuries that damage the nervous system, diabetic neuropathy (diabetes-induced nerve damage) or epilepsy

Erectile dysfunction might be your body’s way of telling you you need to get that overdue check-up. Be on the lookout for sudden ED and temporary ED, both of which could be a sign to make an appointment with a healthcare professional.

Talk to a Healthcare Provider About Your Dosage

Sometimes, your prescription does need to be adjusted — but if that’s the case, you’ll need to speak to your healthcare provider, first.

For on-demand usage, a starting tadalafil dosage is typically10 mg. A healthcare professional might increase your dosage to 20 mg if the 10 mg dose isn’t effective. They could also decrease the prescription to 5 mg if you’re experiencing side effects.

If you’re using Cialis daily, you’ll probably be prescribed 2.5 mg or 5 mg.

Everybody’s tolerance is different. While some people can take 20 mg of Cialis without issues, others might find that 5 mg causes unbearable side effects. 

You may have options for increasing your tadalafil dosage — but it’s really crucial to get medical advice instead of figuring it out on your own. 

Try a Different ED Medication 

Quite a few PDE5 inhibitors can be used to treat erectile dysfunction. If Cialis isn’t working for you, a different medication could yield better results.

Other ED medications include:

You could also try our hard mints. These chewable ED meds contain the same active ingredients as brand-name pills in safe, effective amounts. 

Make Healthy Lifestyle Changes

Healthy lifestyle changes can benefit your body and mind in more ways than one. There are many natural ways to protect erectile function, which you could use instead of or alongside Cialis.

Some top tips include:

  • Maintaining a healthy weight

  • Reducing alcohol use

  • Quitting smoking

  • Avoiding illicit drug use

  • Exercising regularly 

  • Eating a healthy, balanced diet

  • Getting enough sleep (and addressing sleep disorders like insomnia or sleep apnea)

  • Managing stress in a healthy way

Instilling healthy habits can be overwhelming, especially if many aspects of your lifestyle need improvement. You could start by identifying one or two habits you’d like to work on and gradually working toward a more comprehensive lifestyle change.

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Taking 40 mg of Cialis may be tempting, especially if your current dose isn’t working. But it’s important to take medications as prescribed — increasing your Cialis dosage without medical supervision can be very dangerous. 

  • Higher dosage equals higher risk. The more Cialis you take, the more likely you are to experience side effects — including some really serious side effects, like priapism.

  • And it won’t necessarily be more effective. Not only is 40 mg of tadalafil more dangerous, but it might not actually work better than your prescribed dosage. Remember, Cialis doesn’t automatically give you an erection.

  • The good news? There are other treatment options. If Cialis isn’t working, speak with a healthcare professional about changing your dosage or trying other erectile dysfunction medications. Healthy lifestyle changes — with or without Cialis — can also improve your erections.

If you’d like to change your Cialis dosage or try a different ED treatment, consulting a healthcare provider should be your first port of call.

When you’re ready to take that step, we can put you in touch with a licensed professional through our telehealth platform.

8 Sources

  1. Cialis (tadalfil) tablets label. (n.d.). Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/021368s20s21lbl.pdf
  2. Dhaliwal, A., & Gupta, M. (2023). PDE5 Inhibitors. In StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
  3. Evans JD, Hill SR. (2015). A comparison of the available phosphodiesterase-5 inhibitors in the treatment of erectile dysfunction: a focus on avanafil. Patient Prefer Adherence. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4542406/
  4. Kc HB, Shrestha A, Acharya GB, Basnet RB, Shah AK, Shrestha PM. Tamsulosin versus tadalafil as a medical expulsive therapy for distal ureteral stones: A prospective randomized study. Investig Clin Urol. 2016 Sep;57(5):351-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017565/
  5. Sooriyamoorthy T, Leslie SW. Erectile Dysfunction. [Updated 2023 May 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562253/
  6. Tadalafil: Medlineplus drug information. (2023). Retrieved November 13, 2023, from https://medlineplus.gov/druginfo/meds/a604008.html
  7. Treatment for Erectile Dysfunction. (2017). Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/treatment
  8. Yafi, F. A., Jenkins, L., Albersen, M., Corona, G., Isidori, A. M., Goldfarb, S., Maggi, M., Nelson, C. J., Parish, S., Salonia, A., Tan, R., Mulhall, J. P., & Hellstrom, W. J. (2016). Erectile dysfunction. Nature reviews. Disease primers, 2, 16003. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027992/
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Mike Bohl, MD

Dr. Mike Bohl is a licensed physician, a Medical Advisor at Hims & Hers, and the Director of Scientific & Medical Content at a stealth biotech startup, where he is involved in pharmaceutical drug development. Prior to joining Hims & Hers, Dr. Bohl spent several years working in digital health, focusing on patient education. He has also worked in medical journalism for The Dr. Oz Show (receiving recognition for contributions from the National Academy of Television Arts and Sciences when the show won Outstanding Informative Talk Show at the 2016–2017 Daytime Emmy® Awards) and at Sharecare. He is a Medical Expert Board Member at Eat This, Not That! and a Board Member at International Veterinary Outreach.

Dr. Bohl obtained his Bachelor of Arts and Doctor of Medicine from Brown University, his Master of Public Health from Columbia University, and his Master of Liberal Arts in Extension Studies—Journalism from Harvard University. He is currently pursuing a Master of Business Administration and Master of Science in Healthcare Leadership at Cornell University. Dr. Bohl trained in internal medicine with a focus on community health at NYU Langone Health.

Dr. Bohl is Certified in Public Health by the National Board of Public Health Examiners, Medical Writer Certified by the American Medical Writers Association, a certified Editor in the Life Sciences by the Board of Editors in the Life Sciences, a Certified Personal Trainer and Certified Nutrition Coach by the National Academy of Sports Medicine, and a Board Certified Medical Affairs Specialist by the Accreditation Council for Medical Affairs. He has graduate certificates in Digital Storytelling and Marketing Management & Digital Strategy from Harvard Extension School and certificates in Business Law and Corporate Governance from Cornell Law School.

In addition to his written work, Dr. Bohl has experience creating medical segments for radio and producing patient education videos. He has also spent time conducting orthopedic and biomaterial research at Case Western Reserve University and University Hospitals of Cleveland and practicing clinically as a general practitioner on international medical aid projects with Medical Ministry International.

Dr. Bohl lives in Manhattan and enjoys biking, resistance training, sailing, scuba diving, skiing, tennis, and traveling. You can find Dr. Bohl on LinkedIn for more information.

Publications

  • Younesi, M., Knapik, D. M., Cumsky, J., Donmez, B. O., He, P., Islam, A., Learn, G., McClellan, P., Bohl, M., Gillespie, R. J., & Akkus, O. (2017). Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo. Acta biomaterialia, 63, 200–209. https://www.sciencedirect.com/science/article/abs/pii/S1742706117305652?via%3Dihub

  • Gebhart, J. J., Weinberg, D. S., Bohl, M. S., & Liu, R. W. (2016). Relationship between pelvic incidence and osteoarthritis of the hip. Bone & joint research, 5(2), 66–72. https://boneandjoint.org.uk/Article/10.1302/2046-3758.52.2000552

  • Gebhart, J. J., Bohl, M. S., Weinberg, D. S., Cooperman, D. R., & Liu, R. W. (2015). Pelvic Incidence and Acetabular Version in Slipped Capital Femoral Epiphysis. Journal of pediatric orthopedics, 35(6), 565–570. https://journals.lww.com/pedorthopaedics/abstract/2015/09000/pelvic_incidence_and_acetabular_version_in_slipped.5.aspx

  • Islam, A., Bohl, M. S., Tsai, A. G., Younesi, M., Gillespie, R., & Akkus, O. (2015). Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair. Clinical biomechanics (Bristol, Avon), 30(7), 669–675. https://www.clinbiomech.com/article/S0268-0033(15)00143-6/fulltext

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