Which Erectile Dysfunction Treatment Is Best For Me?

Sildenafil, sold under the brand name Viagra, was first licensed to treat erectile dysfunction (ED) in 1998.^[1] Since then, multiple other treatments for ED have been approved and licensed for use in the UK.

With a range of options available, you may have questions about their effectiveness, the differences between them, and ultimately, which one is right for you.

To help answer these, we’ve summarised how ED treatments work, the benefits of each option, and their potential side effects in this guide. We’ve also included findings from clinical research, allowing you to make an informed decision about your treatment.

How do erectile dysfunction treatments work?

In simple terms, the majority of oral erectile dysfunction (ED) treatments work by stopping blood vessels in the penis from constricting (getting tighter). This lets more blood flow to the penis after arousal, leading to firmer and longer-lasting erections.

While they help you get and maintain an erection, they don’t make you more sexually stimulated. You need to be aroused already for it to work, as the medication affects physical processes in your body, not mental ones.

To understand how ED treatments work in more detail, it’s important to know what happens in your body when you get an erection. This can be broken down into 4 stages:

1. Nitric oxide release

When you become sexually aroused, nitric oxide (NO) is released from the spongy tissue in the penis.

2. Guanylate activation

The release of NO activates an enzyme called guanylate cyclase. This results in increased levels of cyclic guanosine monophosphate (cGMP), a substance that relaxes the smooth muscle in the penis.^[2]

3. Increased blood flow

When cGMP relaxes the smooth muscles, more blood can flow into the penis, leading to an erection.

4. PDE-5 release

Once arousal diminishes, an enzyme called phosphodiesterase type 5 (PDE-5) is released. PDE-5 breaks down cGMP, preventing the relaxation of smooth muscle. This restricts the blood flow to the penis and causes the penis to become flaccid again.

Most oral ED treatments work at this 4th stage. They are known as PDE-5 inhibitors because they block the action of PDE-5.^[3] This leads to higher levels of cGMP, as the PDE-5 enzyme can break down less of it.

The result is longer-lasting, harder erections as the smooth muscle stays relaxed for longer and lets more blood flow into the penis.^[4]

If you're looking for more in-depth information on ED, read our Everything You Need To Know guide.

Comparing different erectile dysfunction treatments

Oral medications are the most common treatments for erectile dysfunction (ED). However, non-oral alternatives are also available.

Like many medications, ED treatments are available in branded and generic versions. Generic medications have the same effect, are as safe, and work in the same way as branded ones.

Generic medications like sildenafil still need to be licensed by the Medicines and Healthcare products Regulatory Agency (MHRA) to ensure that they’re safe and effective before they can be prescribed in the UK.

Oral ED medication

We prescribe four types of oral ED medication, based on their active ingredients: sildenafil, tadalafil, vardenafil, and avanafil.

Sildenafil treatments

Sildenafil (Generic Viagra)

Sildenafil is the generic version of Viagra and Viagra Connect. The active ingredient in it, as well as Viagra and Viagra Connect, is also called sildenafil.

Sildenafil is a PDE-5 inhibitor, so it blocks the action of the PDE-5 enzyme. PDE-5 breaks down cGMP, a substance that relaxes the smooth muscle in the penis and lets more blood flow in, leading to an erection.

By blocking PDE-5, Sildenafil causes more cGMP to stay in the penis, meaning longer-lasting and firmer erections.

It takes around 30 minutes to 1 hour for it to start working. As it typically remains effective for 4 to 6 hours, Sildenafil can be taken as needed before sex and is better suited for planned sexual activity.

It’s available in 25mg, 50mg, and 100mg options. 50mg is the recommended starting dose to treat ED. If you experience side effects while taking 50mg, you can try the lower 25mg. On the other hand, if you are not getting the desired effect from the starting dose, this can be increased to 100mg.

Viagra

Viagra is the branded version of Sildenafil. It works in the same way, but is priced higher as it’s a branded ED treatment.

Viagra Connect

Viagra Connect contains 50mg of sildenafil per tablet. It does not need a prescription, so it can be purchased over the counter or online after a medical assessment to ensure it’s safe for you.

The decision by the Medicines and Healthcare products Regulatory Agency (MHRA) to allow the sale of Viagra Connect without a prescription in the UK was made after considering how safe it was at the 50mg dose it’s offered at (the recommended medium-strength dose of sildenafil), the risk of side effects, and the need for a medical assessment.

Tadalafil treatments

Tadalafil (Generic Cialis)

Tadalafil contains the active ingredient tadalafil, which is also the active ingredient in Cialis and Cialis Together.

Tadalfil works in the same way as Sildenafil, but its effects last much longer than Sildenafil. It can be effective for up to 36 hours after it's taken, so it’s better suited if you have sex frequently, or more spontaneously.^[5]

It comes in two different forms:

• Tadalafil 10mg and 20mg (also known as Tadalafil 36-hour) can be taken as needed before sex, like Sildenafil.
• Tadalafil 2.5mg and 5mg (also known as Tadalafil Daily) is designed to be taken every day, so there’s a consistent amount of the medication in your body. This means the medication will always be active, letting you have sex at any time.

Cialis

Cialis is the branded version of Tadalafil. It works in the same way as Tadalafil but is priced higher as it is a branded medication.

Cialis Together

Cialis Together contains 10 mg of tadalafil. Like Viagra Connect, it’s offered at the recommended medium-strength dose of tadalafil, as this was deemed safe for patients to take without a prescription by the Medicines and Healthcare products Regulatory Agency (MHRA).

As a result, Cialis Together can be purchased online or over the counter. You’ll still be required to complete a medical assessment to purchase Cialis Together so a pharmacist can confirm it’s safe for you to take.

Vardenafil treatments

Vardenafil (Generic Levitra)

Vardenafil is also a PDE-5 inhibitor, so it works in the same way as other oral ED treatments. Vardenafil is recommended for men with diabetes over Sildenafil or Tadalafil, as it can be more effective and have fewer side effects.

It takes a similar time to work as other oral ED medications - around 25 minutes to 1 hour. The medication also remains active for 4 to 5 hours.

Levitra

Levitra is the branded version of Vardenafil. Like Viagra and Cialis, Levitra is more expensive because it's branded. The effects are identical to Vardenafil.

Avanafil treatments

Spedra (Avanafil)

Spedra is another type of PDE-5 inhibitor that’s similar to Sildenafil, Tadalafil, and Vardenafil.

Spedra is designed to be absorbed faster than other oral ED medications, so you’ll experience the effects quicker.

It can start working in 15 to 30 minutes, while other PDE-5 inhibitors typically take at least 30 minutes.^[6]

Try our ED trial pack that offers combinations of ED treatments at their recommended starting doses to find the medication that suits you best.

Non-oral ED treatments

VaxAid Deluxe

The VaxAid Deluxe is a physical treatment that uses a vacuum pump to help get an erection. It can be used in water during a bath or shower, or with air pressure to create a vacuum. The pressure encourages blood to flow into the penis, and it can be released and repressurised repeatedly to exercise the blood vessels.

Other non-oral ED treatments

Other non-oral treatments, such as creams and injections, claim to be effective at treating ED. There is no scientific evidence that suggests these treatments are effective or help manage the physical causes of ED.

Avoid using any treatments that have not been licensed by the Medicines and Healthcare products Regulatory Agency (MHRA), as their safety and effectiveness cannot be confirmed. You should consult our pharmacy team or your GP before taking any ED treatment.

What are the most popular erectile dysfunction treatments?

Based on Google Trends data, which tracks the average number of searches on its search engine, Viagra and its generic version Sildenafil are the most popular erectile dysfunction (ED) treatments as of November 2025. They’ve also consistently been the most searched for treatments over the past 5 years.^[7]

This is likely because Viagra has been on the market the longest and has the most brand recognition.

Sildenafil (generic Viagra) is also the recommended first-line treatment for ED that’s prescribed by the NHS.^[8]

However, Cialis and Tadalafil (its generic version) have been increasing in average searches, especially since 2022.

Both Viagra and Cialis are popular options in 2025, as they are suited to different people and their personal needs because of the duration of their effects.

Things to consider when choosing erectile dysfunction treatments

Dosage strength

Dosage strength is an important consideration when choosing erectile dysfunction (ED) treatments. Too high a dose may result in side effects, while too low a dose might not provide the desired results.

It’s recommended to start with a lower or medium-strength erectile dysfunction (ED) treatment before considering stronger doses.

The time it takes for treatments to work

Some ED medications start working faster than others. For instance, Spedra (avanafil) is specifically designed to be absorbed quickly by the body, meaning you’ll experience its effects faster than other oral treatments.

Spedra could be a better choice for you if you don’t tend to plan sex ahead of time or want to be able to get an erection as fast as possible.

You can speak to our pharmacy team if you want to discuss which ED treatments suit your needs best.

Potential side effects

Like all medications, experiencing side effects is possible when taking ED treatments. While these are typically mild, you may experience side effects differently from someone else or not get any side effects at all.

The most common side effects include:

• headaches
• feeling sick (nausea)
• hot flushes
• indigestion
• stuffy nose
• feeling dizzy

Refer to the patient information leaflet that’s included with your ED medication for further information on potential side effects.

Make sure you read through the leaflet before you start your treatment.

The duration of their effects

Most ED medications, except Tadalafil and Cialis, are typically effective for around 4 to 6 hours. This does not mean you’ll have an erection for the whole duration. It means that the medication remains active in your body, ready to help you get and maintain an erection, for 4 to 6 hours.

Treatments containing tadalafil are designed to last much longer than other PDE-5 inhibitors. Tadalafil breaks down more slowly compared to other ED treatments, so it stays in your body for longer.

This means they’re better suited if you have sex regularly or more spontaneously, as it can work for up to 36 hours. Tadalafil is also available in low daily doses (2.5mg and 5mg) that can be taken daily to maintain a consistent level of its active ingredient in the body. This lets you achieve or maintain an erection at any time.

Branded or generic treatments

Branded and generic versions of a particular ED treatment contain the same active ingredient. For instance, Viagra (a branded treatment) and Sildenafil (Viagra’s generic version) both contain the active ingredient sildenafil. However, branded medications are typically more expensive than generic medicines.

Generic medications are medically identical, equally safe, and just as effective as their branded versions. They still need to be licensed by the Medicines and Healthcare products Regulatory Agency (MHRA) to be prescribed in the UK and undergo the same approval process as any other medication to ensure they’re safe and effective.