How Does Cialis Work and What to Do If It Doesn’t

Like  Viagra^®, Stendra^®, and Levitra^®, Cialis^® (the brand name of the active ingredient tadalafil) is highly effective as a treatment for erectile dysfunction (ED). But no medication has a 100 percent success rate, and Cialis is no exception. Even after you take Cialis, you could still experience some symptoms of ED — not to mention side effects. 

Worrying about side effect risks while not seeing the results you want can be stressful, and it’s normal to worry if you’re not getting erections like you’d expect. 

We know you got here by searching questions like “how long for Cialis to work” and “how fast does Cialis work,” but understanding how Cialis works is the most important part of the picture. And while you’re at it, learning more about it will give you a better understanding of what to expect (and where to look for signs that the medication isn’t working).

Below, we’ve explained how this medication functions and why it might not be working. We’ve also shared some things you can do if Cialis doesn’t treat your ED.

The U.S. Food and Drug Administration first approved Cialis in 2003 as a treatment option for ED. 

It’s a phosphodiesterase type 5 (PDE5) inhibitor. PDE5 inhibitors like Cialis treat the symptoms of erectile dysfunction by inhibiting the PDE5 enzyme, which has the effect of keeping the smooth muscles in the arteries that supply blood to the penis relaxed. This makes it easier for blood to move into the erectile tissues of your penis, which leads to an erection.

PDE5 inhibitors don’t specifically target your penis but improve blood flow throughout your body. Theyy also don’t give you an erection until you’re sexually aroused.

Studies of tadalafil show that it improves erections and enhances sexual performance even at a relatively low dose.  

What does Cialis do that other ED meds don’t? It stays in your body longer. Thanks to its long half-life, Cialis can provide relief from erectile dysfunction symptoms for up to 36 hours. Cialis doesn’t cause an erection for 36 hours, but it increases the potential for improved erectile response during that time when sexual stimulation occurs. 

So, how fast does Cialis work?

For most people, Cialis typically starts working within 30 minutes to two hours. 

But depending on the Cialis dose your doctor prescribes (and how they suggest you take it) that may mean different things for your ability to get and maintain an erection now, later, and tomorrow.

Cialis is available in two dosage formats:

• As-needed for whenever the mood strikes

• Once-daily for daily use

A daily dose works around-the-clock, helping you achieve an erection anytime you get aroused. As-needed doses, on the other hand, can work for up to 36 hours, but you need to make sure you’re taking it at the right time, ideally shortly before sexual activity. 

If you’re concerned about making sure you’re ready for sex and wondering when to take Cialis, it’s best to talk to a healthcare provider about any questions you may have. 

Generic tadalafil is also FDA-approved to treat benign prostatic hyperplasia (BPH). BPH is a non-cancerous enlargement of the prostate that affects up to 90% of men in their 70s. 

Healthcare professionals also prescribe tadalafil for pulmonary arterial hypertension (PAH). PAH is high blood pressure in the vessels carrying blood to your lungs. It affects about 25 people per million. 

Depending on your needs, your provider may prescribe the following doses of Cialis:

• 2.5 mg

• 5 mg

• 10 mg

• 20 mg

The dose generally depends on why you’re taking it. The as-needed starting dose is typically 10 mg, going up to 20 mg. 

For daily use, your doctor will likely recommend starting with a dose of 2.5 mg before increasing to 5 mg. Daily dosing is often used for men who have sex more frequently or prefer a steady level of medication in their system.

Clinical trials involving Cialis have consistently shown it’s highly effective at treating ED in a large number of men. In clinical trials, between 68% and 77% of men who took 10 mg of Cialis were able to successfully engage in penetrative sex. Among those who took the 20 mg dose, success rates increased to 76% to 85%.

Cialis works by increasing blood flow to your penis. So, if your ED isn’t caused by impaired blood flow, you might not see an improvement in your erection quality with medication. 

Unfortunately, the same drug that works wonders for one person, might not work for you. Here’s why Cialis might not be delivering the results you’re looking for:

• You don’t respond to the active ingredient

• You’re using it incorrectly

• The dose isn’t right for you

• You have performance anxiety or psychological ED

• You have a serious underlying condition that’s causing ED

• You have a porn addiction

Let’s look at these reasons Cialis can fail in more detail.

Medication Effectiveness

Cialis not working? Here’s the thing: No medication is 100% effective. 

It could be that — for whatever reason — Cialis works a little differently in your body.

Some clinical trials that led to the FDA-approval of Cialis reported success rates over 70% at a dose of 10 mg. 

So, while these medications are generally effective, that still leaves a large percentage of men who don’t respond.

You’re Not Using Cialis Correctly

Cialis is designed to be used under specific conditions for maximum effectiveness. While you should always take Cialis exactly as your healthcare provider tells you to, it’s generally recommended that for optimal results, you should:

• Take Cialis at least 30 minutes before sexual activity: Since Cialis is a long-lasting medication, you can take it several hours before sex without having to worry about its effects wearing off.

• Avoid drinking alcohol or taking recreational drugs: Not only can alcohol make Cialis and other medications less effective, it can also affect your blood flow. This side effect of mixing Cialis with alcohol makes it harder to get an erection even with the help of medication.

• Ask your doctor about interactions: Cialis may also be affected by interactions with other medications, as well as certain foods — like grapefruit juice. It’s important to talk to your doctor about potential interactions. 

These warnings appear on the prescribing information labels approved by the U.S. Food and Drug Administration (FDA).

You’re Not Using the Right Dose of Cialis

Cialis comes in several doses: 2.5 mg, 5 mg, 10 mg, and 20 mg. Most of the time, the 5 mg, 10 mg and 20 mg dosages are used as-needed for the treatment of erectile dysfunction.

Lower doses of Cialis, like 2.5 mg and 5 mg tablets, tend to be used as daily doses to treat mild ED and medical conditions such as benign prostatic hyperplasia (BPH). 

If your healthcare provider prescribes a lower dosage of Cialis and you find it’s not fully effective, it’s a good idea to discuss your results with them to see if switching you to a higher dose is appropriate. 

You’re Experiencing Performance Anxiety

Sexual performance anxiety can also lead to ED symptoms. This refers to a feeling of nervousness and anxiety before and during sex. If you’re affected by sexual performance anxiety, it’s typical to feel worried about Cialis’ effectiveness the first few times you use it.

This nervousness can result in worse ED than normal even after sexual stimulation, meaning that Cialis might not be totally effective as a treatment. 

If you find that Cialis doesn’t work the first time you use it at a normal dosage, it’s a good idea to wait until you feel relaxed and confident before judging Cialis’s performance fairly. You could even practice masturbating with it first, to see how things go if you have worse anxiety with partnered sex. 

If problems persist, it’s a good idea to let your healthcare provider know. They may recommend a different dose, or even switch you to another ED medication altogether.

Your ED is Caused by a Psychological Condition

Cialis is designed to treat erectile dysfunction’s physical causes, like poor blood flow to the erectile tissues of your penis. It’s not a psychiatric medication and isn’t designed to be a treatment for psychological causes of ED. 

Erectile dysfunction can be associated with anxiety, stress, and depression. If you have a mental illness or other psychological condition that affects your sexual performance, the use of Cialis and other ED drugs might not be completely effective. Your healthcare provider may suggest alternative therapies such as anxiety and depression medications or talk therapies. 

Your ED is Caused by a Physical Health Condition

Erectile dysfunction is often associated with health conditions such as: 

• Hypertension (high blood pressure)

• Diabetes

• Peyronie's disease

• Nerve damage

• Enlarged prostated

• Cardiovascular disease

• Low testosterone

As we mentioned above, tadalafil works by increasing blood flow to the erectile tissues of your penis. But if your ED is caused by another physical condition that doesn’t affect blood flow, your ED may not be completely treated by Cialis.

For example, issues like low testosterone can also affect both your sexual performance and your general level of interest in sex. Because Cialis isn’t a hormonal medication, it might not be completely effective at treating ED caused by low testosterone. 

Porn addiction is Affecting Your Sexual Performance

Frequent or excessive porn use may negatively affect your sexual performance by altering your sexual expectations, arousal patterns, and perceptions of real-life intimacy. This isn’t about occasional viewing, but rather compulsive use, which may make it harder to become aroused or perform sexually with a partner.

Porn consumption can also potentially result in anxiety around sex, which can contribute to erectile dysfunction.

Since this is a psychological cause of ED, it often can’t be fully treated with PDE5 inhibitors. Our guide to porn-induced ED explains this phenomenon in more detail and shares techniques that you can use to avoid letting porn affect your sex life.

According to the FDA, the most common side effects of Cialis include:

• Headache

• Indigestion

• Back pain

• Muscle pain

• Flushing of the skin

• Stuffy nose 

More serious side effects include:

• Vision loss

• Hearing loss

• Prolonged erection (also known as priapism)

• Low blood pressure

• Heart problems

Additionally, you’ll want to talk to your healthcare provider about the potential for drug interactions if you’re taking other medications. Some medications known to interact with Cialis include:

• Alpha-blockers

• Nitrates like nitroglycerin and amyl nitrate

• “Poppers” 

• Antifungal medications like itraconazole and ketoconazole

• Riociguat, a drug used to treat pulmonary hypertension

Other PDE-5 inhibitors that have been FDA-approved to treat ED in the United States include:

• Sildenafil (Viagra)

• Vardenafil (Levitra, Staxyn)

• Avanafil (Stendra)

All PDE-5 inhibitors approved in the United States are effective treatments for ED, but Cialis works longer.

Here are some frequently asked questions people ask about Cialis.

How often can you take Cialis?

Cialis comes in two forms, one that you take every day at the same time and one you take as needed for sexual activity. It’s important not to take Cialis more than once per day. 

How do I know what dose is right for me?

Your doctor can determine the Cialis dose that’s right for you. They’ll likely recommend starting with a lower dose and increasing to a higher dose over time if needed.

How long before Cialis works?

Cialis often reaches peak concentration in your blood after about 2 hours.

Cialis works for many men with ED. But if you’re taking Cialis and not getting the results you want, remember some key points:

• ED medications are science-backed. Erectile dysfunction treatments like Cialis are generally (but not always) effective when used correctly.

• Using them incorrectly can impact medication efficacy. Taking the wrong dosage for you or not following instructions can cause Cialis not to work.

• Cialis might also fail if your ED is related to psychological issues. Performance anxiety, intimacy issues, low self-confidence, and depression can all affect your erections.

• FDA-approved prescription medications like Cialis are generally safer than other remedies. They’re also more effective than supplements you might get elsewhere.

If Cialis isn’t working for you, it’s a good idea to talk to your healthcare provider about alternative options. They may adjust your dose, guide you on how to achieve best results, or switch you to another medication.