The Independent Pharmacy

Tadalafil (Cialis) vs Sildenafil (Viagra)

Andy Boysan
Andy Boysan
BPharm GPhC 2047716
Director & Superintendent Pharmacist

For many men facing the challenge of erectile dysfunction (ED), exploring the differences between treatment options like tadalafil vs sildenafil (or Cialis vs Viagra to use their brand names) can be a key step in finding a solution that brings both comfort and confidence.

Sildenafil, commonly referred to by the brand name Viagra, works very quickly, which makes it well-suited for spontaneous sexual activity. In contrast, tadalafil (Cialis) stays in the body for longer and so can be effective over a longer duration. Understanding these characteristics is important when starting treatment for ED.

In this guide, we'll cover the key differences between sildenafil and tadalafil so you can make the choice that’s right for you.

Key Findings:

  • Sildenafil (Viagra) acts fast. It can be effective in just 30-60 minutes, but only remains active in the body for 4-6 hours.
  • Tadalafil (Cialis) takes between 30 minutes to two hours to work but stays in the body for much longer, making it possible to achieve erections for up to 36 hours after a single dose.
  • Both medications improve erection firmness and have comparably mild side effect profiles.

Sildenafil vs Tadalafil at a Glance

Feature Sildenafil (Viagra) Tadalafil (Cialis)
Onset of Action 30 - 60 minutes
30 minutes to
2 hours
Duration of Effect 4-6 hours Up to 36 hours
Dosage Options 25-100mg, taken
as needed
10-20mg for
as-needed use;
5mg daily
Flexibility for Use Suited for immediate
use
Flexible for planned
or spontaneous encounters
Side Effects Headaches, flushing,
ndigestion, nasal congestion,
dizziness, back pain,
visual changes
Headaches, flushing,
indigestion, nasal congestion,
dizziness, back pain
Erection Hardness Slightly firmer peak
erections in some cases
Longer-lasting erection
capability over 36-hour
period
Suitability Ideal for shorter-term
treatment and immediate needs
Better for longer-lasting
effectiveness and flexibility

Sildenafil vs Tadalafil: What’s the Difference?

Sildenafil and tadalafil have emerged among the most effective and commonly prescribed oral medications for effectively treating erectile dysfunction (ED). Both sildenafil and tadalafil work by blocking certain chemicals in the body, which helps increase blood flow to the penis, making it easier to get and keep an erection.

However, there are some important differences between these ED treatment options:

  • Sildenafil is sold widely under the brand name Viagra, while tadalafil goes by the brand name Cialis (generic versions are also available).
  • Sildenafil works fast, producing effects within 30-60 minutes on average.
    tadalafil stays in the body for longer, making it possible to achieve erections for up to 36 hours.
  • Both medications have similar side effects, but sildenafil is more likely to cause temporary visual changes like blurred or blue-tinted vision.

When choosing between sildenafil and tadalafil, think about how quickly you need the medication to work and how long you’d like it to be effective for. It’s also important to consider the side effects of each type of ED pill.

Discussing these considerations with a healthcare professional can help you select the best treatment option for you.

Sildenafil Tablets
Sildenafil Tablets
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Sildenafil vs Tadalafil: How Do They Work?

Sildenafil and tadalafil both work by increasing blood flow to the penis. This allows you to get and maintain an erection when sexually aroused.

The medications relax muscles and widen blood vessels in your penis, which allows more blood to flow into them, making your penis bigger and firmer so that you can have sex. They do this by stopping a chemical called PDE-5 that can affect blood flow in the penis.

These medications won’t produce erections on their own without stimulation. In other words, you need to be sexually aroused for them to have an effect.

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Sildenafil vs Tadalafil: How Much to Take and When

If it’s your first time using sildenafil, you’ll probably be recommended to start with a 50mg dose, and this should be taken around an hour before sexual activity. However, you may find that you need a little less or more to achieve a satisfactory erection, and for this reason, sildenafil dosage may be adjusted between 25mg and 100mg depending on your individual needs.

However, please note that no single dose should exceed 100mg. This is because there are health risks associated with higher doses of sildenafil, and larger doses will increase your risk of experiencing side effects. No more than one dose of sildenafil should be taken in any 24-hour period.

In contrast, tadalafil stays in your body for up to 36 hours. It should be possible for you to achieve an erection at any point in that period, provided you are sexually aroused. This makes it ideal for people who may want to have sexual activity several times during the course of a day. Tadalafil can be taken either as needed, or daily if you have an active sex life.

An initial dose of 10mg is usually recommended, and this should be taken at least 30 minutes prior to sexual activity. This dose may be increased to 20mg or adjusted between 10mg and 20mg depending on your body’s response. 20mg is the maximum single dose of tadalafil and no more than this should be taken in any 24 hour period.

If you want to have sex at least two or three times each week, a daily tadalafil tablet may suit you better. A dose of 2.5-5mg is recommended for daily use. This will slowly build up in your system, giving you erection support every time you have sex. Most men can expect to start experiencing the benefits of daily tadalafil 3-5 days after treatment begins.

As with any new medication, following your doctor’s instructions for ED drugs is essential. Always follow dosing guidelines to ensure that you are using your medication safely. Doing so will also ensure that you get the optimal benefit from your erectile dysfunction treatment. Talk to your healthcare provider if you have additional questions about how to take sildenafil or tadalafil properly.

Sildenafil vs Tadalafil: Which One Acts Faster?

Sildenafil typically starts working in 30-60 minutes.

In comparison, tadalafil can take as little as 30 minutes to be effective, but may take up to two hours to reach maximum concentrations in the blood. This means that you may only be able to achieve an erection two hours after taking your dose of tadalafil.

Tadalafil (Cialis) is often called “the weekend pill” due to its longer duration of action. As we know, just one dose could be enough to provide erections as needed over the course of an entire weekend.

Winner: Sildenafil (faster onset)

Sildenafil vs Tadalafil: Which Lasts Longer?

On average, sildenafil remains in the body for just 4-6 hours before it’s no longer effective. So, after taking sildenafil, you’ve generally got a 4-6 hour window to have sex before the effects of the medication wear off. This means that sildenafil is well suited for short-term treatment in preparation for a specific sexual encounter.

In contrast, tadalafil has a significantly longer duration with a half-life of 17.5 hours on average. Clinically, this means men can experience up to 36 hours of enabled erections after taking tadalafil.

Clearly, tadalafil’s duration outpaces sildenafil by a wide margin. While sildenafil lasts for several hours, a single dose of tadalafil can enable erections for up to a day and a half.

Winner: Tadalafil (longer lasting)

Sildenafil vs Tadalafil: Which Leads to Harder Erections?

Evaluating and comparing the hardness and quality of erections is important to men seeking sexual satisfaction from erectile dysfunction (ED) treatment.

In a study comparing the two, sildenafil showed a small advantage in helping a slightly higher number of men achieve their firmest erections. This suggests Viagra (sildenafil) may promote firmer peak erections for some patients.

However, tadalafil generated longer-lasting erection capability that study volunteers often preferred over shorter periods of maximal hardness.

Ultimately, which is “best” will come down to personal preference – whether you want to enjoy slightly firmer erections for a shorter period of time, or have a larger window with which to engage in sexual activity. It’s also important to note that results can and may vary between patients too.

Winner: Both (similar effectiveness)

Sildenafil vs Tadalafil: Side Effects

Both ED treatments may cause:

  • Headaches
  • Flushing
  • Indigestion
  • Nasal congestion or a runny nose
  • Dizziness
  • Back pain

These adverse effects typically resolve on their own within several hours.

Sildenafil is more likely to cause temporary visual changes like blurred vision, increased light sensitivity, or a blue tinge to vision. Around 3% of men report these visual disruptions. In contrast, tadalafil (Cialis) does not appear to significantly impact vision for most patients.

On rare occasions, more serious side effects may occur, such as sudden hearing loss or priapism (a painful, prolonged erection). Such severe reactions are unusual and if you experience either, you should seek medical attention immediately.

While neither drug is free from potential adverse effects, the reduced likelihood of visual changes provides a slight safety advantage for tadalafil. However, both medications are generally well tolerated in most men, especially when using the lowest effective dose.

Winner: Tadalafil (milder side effects)

Sildenafil vs Tadalafil: Interactions

When taking any prescription medication, it’s important that you understand potential drug interactions. What this means is that both sildenafil and tadalafil can pose safety risks when combined with certain other drugs.

Medications called nitrates, which are used for heart disease and controlling blood pressure, can have dangerous interactions with these ED medications. The additional blood pressure lowering effects of the medications increases the risk of side effects like fainting, heart attack, or stroke. If you are using nitrate medications, you should not take PDE5 inhibitors like sildenafil or tadalafil.

These ED medications can also interact with other types of drugs, including those commonly prescribed for high blood pressure, fungal infections, bacterial infections, seizures, and HIV treatment. Always inform healthcare providers of any regular prescriptions or over-the-counter products you’re taking when discussing or purchasing ED treatment.

To reduce your risk of complications, have a doctor or licensed pharmacist review your medical history and any medications you are taking before being prescribed erectile dysfunction drugs. And if you experience any side effects, be sure to speak to your doctor or seek the appropriate medical help

Winner: Both (similar safety profiles)

Tadalafil vs Sildenafil: Can They Reverse ED?

A common question among men considering erectile dysfunction (ED) treatment is whether these medications can permanently reverse ED symptoms. Unfortunately, the answer is no.

While they don’t “cure” ED, they are considered to be effective in treating the symptoms. Sildenafil, tadalafil, and other ED drugs can create temporary improvements in erectile capacity but do not treat the underlying causes of ED. However, enhancing sexual function by using ED pills can help to restore your confidence so that you can enjoy improved intimacy in your relationships.

Some research shows that tadalafil may protect erectile tissue health, which could hypothetically slow decline in sexual function over time. However, concrete evidence of this is still lacking. No strong, controlled trial evidence exists showing these drugs definitively slow the progression of or reverse the effects of erectile dysfunction. They are a treatment alone and not a cure.

Can You Get Sildenafil or Tadalafil on NHS Prescription?

Yes, sildenafil is commonly prescribed on the NHS for treating erectile dysfunction. Tadalafil is also available on NHS prescription.

How to Choose the Right ED Option for You

Choosing between sildenafil and tadalafil (or Viagra vs Cialis) for ED treatment is a deeply personal decision, and one that balances your individual health needs and lifestyle preferences with care and understanding. Reflecting on lifestyle factors, and speaking to a healthcare provider, allows you to find the best ED medications for you.

If spontaneity around sexual activity is a priority, sildenafil can support erections just 30-60 minutes after taking a dose. This makes timing sexual encounters easier. However, the ability to get an erection lasts for no more than 4-6 hours for most men.

If you’d prefer a longer sexual window, tadalafil works for up to 36 hours after one dose. The extended duration allows you to experience multi-day periods of intimacy from a single tablet. However, initial onset takes about two hours on average.

Deciding what’s most important to you will help you decide which ED treatment is right for you - whether that’s the speed at which your erectile dysfunction medication works or how long your window of sexual activity lasts. And obviously you’ll need to take into account any health conditions that you have, and any drug interactions you may be at risk of, when making your final choice about which ED treatment is right for you.

A doctor or licensed, registered UK pharmacist will be able to help you find an erectile dysfunction treatment to suit your needs. And since both sildenafil and tadalafil are only available on prescription, you’ll need to speak to a healthcare professional before you can access or start any ED medication.

Take Charge of Your Sexual Health

If you're feeling overwhelmed by erectile dysfunction, remember you're not alone. We invite you to explore treatment options with our discreet and knowledgeable team here at The Independent Pharmacy, where your health and privacy are our top priorities.

We make physician consultations and customised ED treatment convenient through our secure online platform. Begin by completing a short, confidential self-assessment to explore suitable medications like sildenafil or tadalafil.

Our UK-registered clinical team will promptly provide you with a list of treatments tailored to your needs and preferences. Then, you'll receive prescribed treatments delivered privately to your home.

You can also find more information in our erectile dysfunction guides.

Regain confidence in the bedroom – you have the power to take control of your sex life. Contact The Independent Pharmacy to start your journey to effectively managing ED:

We’re standing by, ready to help you discreetly achieve treatment success. Get in touch with us today.

FAQs

Why is Tadalafil so cheap?

Tadalafil is now available as a generic medication since the original patent expired. Generic versions can be produced by competitors, increasing supply and lowering prices through market competition. Branded Cialis still maintains higher pricing.

Does Tadalafil keep you hard after coming?

Individual experiences can vary, but Tadalafil is not proven to directly prolong erections after ejaculation. Its long-lasting effects enable achieving erections when sexually stimulated again during the duration of action.

What is the best pill to stay hard longer?

Among oral ED medications, Tadalafil (Cialis) is considered the longest-lasting option. Effects enabling erections can persist for up to 36 hours from a single dose. This led to its “weekend pill” nickname. However, Tadalafil does not work without sexual stimulation.

Does Cialis make you harder than Viagra?

Small differences may exist in hardness or duration of erections when comparing Tadalafil (Cialis) and Sildenafil (Viagra). But few major studies directly measure comparative efficacy. Both produce firm erections in most men, but patient factors can influence individual responses.

Sources:

Common questions about sildenafil - NHS (www.nhs.uk)

How and when to take sildenafil - NHS (www.nhs.uk)

How and when to take tadalafil - NHS (www.nhs.uk)

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Andy Boysan

Authored by

Andy Boysan
Andy Boysan
BPharm
2047716
Director & Superintendent Pharmacist

Andy is a co-founder and the Superintendent Pharmacist and Director at The Independent Pharmacy.

Daniel Hurley

Reviewed by

Daniel Hurley
Daniel Hurley
MPharm IP
2078790
Pharmacist Independent Prescriber

Dan is an experienced pharmacist having spent time working in both primary and secondary care. He currently supports our clinical team by providing robust clinical governance review of our internal processes and information.