Intima Care

Sildenafil vs Tadalafil: Differences, Duration and Which Suits You

Sildenafil (sold as Viagra and many other brands) and tadalafil (sold as Cialis and others) are the two most commonly prescribed medicines for erectile dysfunction (ED). Both work well for most men, so the real question is which one fits your health, routine and preferences. This guide covers how they differ, how long each lasts, and what to discuss with your doctor.
Medically reviewed by Dr. Muhammad Zaheer Ud Din Ayub

How Do Sildenafil and Tadalafil Work?

Both belong to a group called PDE5 inhibitors. They relax the blood vessels in the penis and increase blood flow, which helps a man get and keep an erection when he is sexually stimulated. Neither causes an erection on its own, and neither raises desire. If you want the basics of ED first, read our guide on causes of erectile dysfunction

Sildenafil vs Tadalafil at a Glance

	Sildenafil	Tadalafil
Common brands	Viagra, Penegra, Vega and others	Cialis and others
Usual strengths	25mg, 50mg, 100mg	2.5mg, 5mg, 10mg, 20mg
Starts working	About 30 to 60 minutes	About 30 minutes to 2 hours
How long it lasts	Around 4 to 6 hours	Up to 36 hours
Effect of food	A heavy, fatty meal can delay it	Little or no effect
Dosing styles	On demand	On demand, or a low daily dose
Typical side effects	Headache, flushing, blue-tinted vision, indigestion	Headache, back pain, muscle aches, indigestion
Other uses	Erectile dysfunction (also pulmonary hypertension at other doses)	Erectile dysfunction, and enlarged prostate (BPH) symptoms

Duration: How Long Does Each Last?

Sildenafil clears from the body faster. Most men feel the effect for about 4 to 6 hours, which suits planned, one-off occasions.

Tadalafil stays in the body much longer, and its effect can last up to 36 hours in some men. That is why it is nicknamed the “weekend pill”. It allows more spontaneity, but a longer-lasting drug also means side effects can last longer, and a longer window to avoid risky combinations (see the safety section).

Speed and Food

Sildenafil works best on a lighter stomach. A heavy, fatty meal can slow it down and make it less effective. Tadalafil is not meaningfully affected by food, so timing around meals is easier.

Daily Low-Dose Tadalafil

Tadalafil can be prescribed as a low daily dose (commonly 2.5mg or 5mg) instead of being taken before sex. This keeps a steady level in the body, so you don’t need to plan. Your doctor may suggest it if you have sex often, or if you also have urinary symptoms from an enlarged prostate. Sildenafil is taken only on demand.

Side Effects Compared

Both are generally well tolerated, and the most common side effects are similar:

• Both: headache, facial flushing, indigestion, nasal congestion, dizziness
• More typical with sildenafil: a temporary blue tint to vision or light sensitivity
• More typical with tadalafil: back pain and muscle aches, which usually ease within a day or two

Seek urgent medical help for chest pain, fainting, sudden loss of vision or hearing, or an erection lasting more than 4 hours.

Safety: Who Should Not Take Either?

Don’t take either medicine, and speak to a doctor first, if you:

• Take nitrate medicines (for chest pain or heart conditions). This combination can cause a dangerous drop in blood pressure
• Have heart disease, a recent heart attack or stroke, or low or uncontrolled blood pressure
• Take alpha-blockers or other blood pressure medicines
• Have serious liver or kidney problems
• Have a history of sudden vision loss (NAION)
• Are under 18

Never take sildenafil and tadalafil together, and don’t take extra doses because the first one “isn’t working”. Limit alcohol, and avoid recreational drugs, especially “poppers” (nitrite inhalants).

Which One Might Suit You?

Only a doctor can decide, but these points are often part of the conversation:

• Sildenafil may suit you if you want a shorter-acting option for planned occasions, and you can take it on a lighter stomach.
• Tadalafil may suit you if you prefer a long window of flexibility, don’t want to think about meals, or may benefit from a low daily dose.
• Consider side-effect history. If you get strong back pain or muscle aches, sildenafil may be preferred. If you are sensitive to flushing or visual changes, tadalafil may be.
• Consider your other health conditions and medicines, which affect safety more than anything else.

It is common for men to try one and switch to the other if it doesn’t suit them, under a doctor’s guidance.

Does a Higher Strength Work Better?

Not always. Many men do well on a lower dose with fewer side effects, and doctors often start low. Don’t assume 100mg sildenafil or 20mg tadalafil is the right place for you to start.

What If Neither Works?

Tablets don’t fix the cause of ED. Often it is linked to diabetes, high blood pressure, high cholesterol, smoking, obesity, low testosterone, stress, anxiety or relationship issues. If tablets haven’t helped, ask your doctor to look for underlying causes. Lifestyle changes such as exercise, better sleep, weight loss and quitting smoking can improve results.

Frequently Asked Questions

Which is better, sildenafil or tadalafil?
Neither is better for everyone. Sildenafil is shorter-acting, and tadalafil is longer-lasting with more flexibility. The right one depends on your health and preferences.

Is Cialis stronger than Viagra?
Not exactly. They are different medicines with different durations. Tadalafil lasts longer, but that doesn’t make it more powerful.

How long does sildenafil last?
Generally about 4 to 6 hours, though this varies.

How long does tadalafil last?
Up to 36 hours in some men.

Can I take them with food?
Tadalafil can be taken with or without food. Heavy, fatty meals can delay sildenafil.

Can I take both together?
No. Never combine them, because the risk of low blood pressure and side effects rises.

Can I take them every day?
Sildenafil is meant for on-demand use. Tadalafil can be prescribed as a low daily dose by a doctor, but don’t start a daily routine on your own.

Is a prescription required in Pakistan?
Both are prescription medicines and should be used under medical guidance, even where they are sold over the counter.

Final Thoughts

Sildenafil and tadalafil are both effective, well-studied ED medicines. The main differences are how long they last, how food affects them, and whether daily dosing is an option. A short chat with a doctor will help you choose the one that suits your health and lifestyle, and keep you safe from dangerous drug interactions.

Related products: link to your sildenafil and tadalafil product pages