Sildenafil vs tadalafil: which ED pill fits your situation?

What is the best ED medication to take?

There is no single best ED pill. For most men, sildenafil and tadalafil work about equally well, and the better choice is the one that fits how and when you have sex. The American Urological Association (AUA) guideline on erectile dysfunction says the PDE5 inhibitors, particularly sildenafil, tadalafil and vardenafil, appear to have similar efficacy in the general ED population.^[1] The guideline also notes a limit: few trials compare the drugs directly with each other.

Both drugs belong to the same class, phosphodiesterase type 5 (PDE5) inhibitors. As the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) explains, they are oral medicines that improve blood flow to the penis. They may help you get and keep an erection.^[2] They do not cause an erection on their own; sexual stimulation is still needed. The AUA guideline reports that incorrect use, such as no sexual stimulation or taking the pill with a large meal, accounts for 56% to 81% of reported treatment failures.^[1]

Onset, duration and food effects are from the AUA guideline; the other uses are from MedlinePlus.^[3] Both are prescription medicines in the US, so the choice is made with a licensed clinician who knows your health history. NIDDK puts it plainly: choosing an ED treatment is a personal decision.^[4]

What pill keeps you hard the longest?

Tadalafil has the longer window. The AUA guideline lists its duration of action as up to 36 hours, against up to 12 hours for sildenafil.^[1] That window is the time in which the drug can help an erection happen with stimulation. It does not mean an erection lasting that long.

The two drugs also differ in how you plan around them. MedlinePlus advises taking sildenafil about 1 hour before sexual activity, at any time from 4 hours to 30 minutes before, and usually not more than once every 24 hours.^[5] Tadalafil taken as needed is usually taken at least 30 minutes before sexual activity, also not more often than once every 24 hours.^[3]

An erection that is painful or lasts longer than 4 hours is a medical problem, not a sign the pill works well: MedlinePlus lists it among the side effects that need urgent medical help.^[5]

Which is better for prostate, Viagra or Cialis?

If you have both ED and the urinary symptoms of an enlarged prostate, tadalafil is the drug with that second use. MedlinePlus lists tadalafil (Cialis) as a treatment for erectile dysfunction and for the symptoms of benign prostatic hyperplasia (BPH), such as hesitation, a weak stream, incomplete bladder emptying and urinary urgency.^[3] For BPH it is taken once a day. Sildenafil has no such use listed on its MedlinePlus page.^[5]

The overlap is common. The AUA guideline reports urinary symptoms from BPH in up to 72% of men with ED, and treats the two as independent risk factors for each other.^[1] If you already take a medicine for BPH, tell your clinician before starting tadalafil: MedlinePlus notes that your doctor may tell you to stop your current BPH medicine.^[3]

This section is about benign prostate enlargement. ED after prostate cancer treatment is a different situation; the AUA guideline notes that men who have had a prostatectomy tend to respond less strongly to PDE5 inhibitors.

Which is better for older men, Viagra or Cialis?

Age alone does not decide it. What matters more for older men is what tends to come with age: heart disease, diabetes and a longer list of medicines. NIDDK stresses that ED is not a routine part of aging.^[4]

The most important check is nitrates. The AUA guideline warns that combining a nitrate with a PDE5 inhibitor can cause a precipitous drop in blood pressure, so men who take nitrates regularly should not use these drugs. Men who carry nitroglycerin for angina should not use it within 24 hours of a PDE5 inhibitor, and possibly longer after tadalafil because it stays in the body longer.^[1] That longer half-life is the one case where tadalafil's long window is a drawback.

Before prescribing either drug, a clinician will ask about heart attack, heart failure, angina, irregular heartbeat, stroke, blood pressure, and kidney or liver disease, which MedlinePlus lists among the conditions to mention.^[5] The AUA guideline also names antidepressants, antifungals, blood pressure drugs and HIV medicines as possible interactions. A full medicine list, including over-the-counter products, is the most useful thing to bring.

Does sildenafil get you harder than tadalafil?

The evidence does not show that either drug gives a firmer erection. The AUA guideline found a pattern of similar efficacy across the medicines on various measures of erectile function, most often the erectile function score of the International Index of Erectile Function (IIEF).^[1] It adds that, given the large number of trials and participants, a real difference between the most studied drugs would probably have shown up.

Higher doses do not change much either. According to the guideline, the average gain from a higher dose is small and often not clinically significant, while side effects rise more clearly with dose. The panel concludes that men should use the lowest dose that produces acceptable results. The most frequently reported side effects are mostly mild to moderate: indigestion, headache, flushing, back pain, nasal congestion, muscle aches, visual disturbance and dizziness.^[1]

Do most men prefer Viagra or Cialis?

There is no reliable answer to which one most men prefer. The AUA guideline points out that the literature generally lacks trials comparing the medicines with each other, and it does not rank one above the other.^[1] Preference studies that do exist are usually small, and a claim that "most men" choose one drug should be read with that in mind.

What the guideline does describe is how the choice should be made: through shared decision-making, in which the clinician explains the options and you weigh them against your own values and routine. In practice, the questions that separate the two drugs are concrete:

• Do you prefer to plan sex, or keep it spontaneous? Tadalafil's longer window or daily dosing suits spontaneity.
• Do meals often come before sex? A high-fat meal slows sildenafil, not tadalafil.
• Do you also have urinary symptoms from an enlarged prostate? Tadalafil covers both.
• Do you carry nitroglycerin? Then neither may be right, and the timing rules matter most for tadalafil.

Which is better, tadalafil 10mg or sildenafil 50mg?

Comparing the milligrams does not tell you which is stronger. Sildenafil and tadalafil are different molecules, so 10 mg of one and 50 mg of the other are not on the same scale. The AUA guideline did not find a dose of either drug that outperforms the other in the general ED population, and it notes that higher doses add little average benefit but more side effects.^[1]

The right strength is set by the prescriber, based on your health, your other medicines and how you respond. MedlinePlus advises taking either drug exactly as directed and not taking more or taking it more often than prescribed.^[3] If a pill does not work, the next step is a conversation about correct use, dose or another treatment, not a second pill.

To prepare for that conversation, write down how often you want to use treatment, what you eat before sex, every medicine you take and any heart or urinary symptoms. Take this list to a licensed clinician or pharmacist. If cost or coverage matters, our guide on how to check whether your insurance covers a treatment walks through the questions to ask your plan. More guides are in our men's health section, and our methodology explains how we source articles like this one.

Frequently asked questions

Is Cialis or Viagra better for daily use?

Tadalafil (Cialis) is the only PDE5 inhibitor FDA-approved for daily dosing. Sildenafil (Viagra) is taken as needed. According to the AUA guideline, daily and on-demand tadalafil appear to work equally well, so daily use is a question of routine rather than strength.

Can I take sildenafil or tadalafil with food?

Yes, both can be taken with or without food. A high-fat meal can delay and weaken the effect of sildenafil, while food does not affect tadalafil.

Can I switch from sildenafil to tadalafil?

Switching is a decision for your prescriber, who can explain how the timing rules differ. Neither drug is usually taken more than once in 24 hours.

Who should not take sildenafil or tadalafil?

Men who take nitrate medicines for chest pain should not use either drug, because the combination can cause a dangerous drop in blood pressure. Heart, kidney, liver or eye conditions also need to be discussed with a clinician first.

Do I need a prescription for sildenafil or tadalafil?

In the United States, both are prescription medicines. A licensed clinician decides whether either is right for you and at what dose.

Sources

1. auanet.org
2. niddk.nih.gov
3. medlineplus.gov
4. niddk.nih.gov
5. medlineplus.gov
6. medlineplus.gov