Authored: 22/05/2022

Viagra is a medication used to treat erectile dysfunction (ED) by increasing blood flow to the penis. It helps to achieve and maintain an erection suitable for sexual activity. It's effective for men with ED.
You can buy Viagra online without a prescription from our UK registered online doctor. After reading the erectile dysfunction information page, you must then complete a short medical questionnaire as part of your order.
Our UK doctors will then review your assessment, and if your order is approved, pass a Viagra prescription to our registered online pharmacy. The pharmacy will then dispense and dispatch your erectile dysfunction medication to your delivery address.
What Is Viagra? | Treatment for erectile dysfunction (impotence) in men |
Viagra Dosing | Take one tablet an hour before sex. Maximum 1 tablet in 24 hours. |
How Does Viagra Work | By increasing blood flow into the penis. |
Effectiveness | ~83% of men will experience a firmer and longer-lasting erection. |
Viagra Price | From £24.95 for brand. £3.75 for Generic. |
Side Effects | Can include nasal congestion, headaches, dizziness and facial flushing. |
Viagra tablets are the original 'little blue pill'. They are a treatment for erectile dysfunction which was made by the US drug company, Pfizer.
These tablets contain the drug Sildenafil Citrate, which is used to treat erectile dysfunction in men.
Unless you're over 65 years of age, Viagra 50mg is the most commonly prescribed starting dose for men with ED. ONE tablet is taken between half an hour to an hour before sexual activity. This dose is ideally taken on an empty stomach and without alcohol to maximise benefits.
If the dose is ineffective, you should NOT take another dose for at least 24 hours. The next time you try it, you may wish to increase your dose to Viagra 100mg instead.
If the dose is very effective, you may wish to half your dosage to 25mg the next time you take Viagra. This can be done either by purchasing 25mg tablets or halving your 50mg pills.
![]() | Viagra 25mg When 50mg tablet is too effective Men aged 65+ starting dose |
Viagra 50mg The usual starting dose | |
| Viagra 100mg When 50mg was not effective |
Viagra belongs to a family of medicines called PDE5 inhibitors. These PDE5 inhibitors help in erectile dysfunction by increasing the blood flow in the blood vessels of the penis when sexually stimulated. An erection relies on a strong flow of blood into the penis. As a result, this increased blood flow helps men who may struggle to achieve an erection normally.
Viagra does not improve libido, only impotence. This means it helps men to get and maintain an erection when sexually aroused. This means sexual stimulation is still required for the medication to work.
Viagra has been shown in trials to work in around 83% of men. The effects of the medication will last 4 to 6 hours. There are certain things you can do to make sure you are getting the full benefit of Viagra:
Recommended using at least 4 times before you consider changing medicine. Increasing from Viagra 50mg to 100mg may be required, or you may need to try an alternative ED medicine.
There can be underlying causes of ED which Viagra for men will not overcome. Examples of these are in cases where someone has suffered a serious spinal injury that has resulted in nerve damage. If you have an underlying condition and have tried Viagra without success, you should seek additional treatment options from your GP.
Tablets which are referred to as “Cheap Viagra”, usually refer to the generic version of the drug. These contain the active ingredientSildenafil.
As the drug is identical, effects should be the same, however Sildenafil is significantly cheaper. You can comapre the two in detail by reading the Viagra vs Sildenafil comparison.
You can read what UK patients have experienced with generic Viagra on our reviews page.
Viagra is a well-tolerated medication, however, there is always a risk of side effects when taking any medicine. It's important you read the patient information leaflet so you are aware of the potential side effects when taking Viagra.
Listed below are some of the more common side effects men taking this medication may experience.
Please read the information leaflet for a list of all possible side effects.
Psychological causes of erectile dysfunction may benefit from counselling therapies. If nerves are the primary cause of erectile dysfunction, psychologists can help in developing strategies to stay calm. This can allow you to better deal with the situations which cause your stress or anxiety.
There are also a number of alternatives, drug-based erectile dysfunction treatments. These include:
Apart from treatments, you can also look at how your lifestyle may be affecting your erectile dysfunction. Obesity, smoking, and drinking can all negatively impact your ability to get and maintain an erection. You may wish to consider reducing your alcohol intake and exercising to help improve your overall health
Product | Branded Viagra | Generic Viagra |
4 tablets | from £24.95 | from £5.89 |
8 tablets | from £43.95 | from £9.49 |
12 tablets | from £61.95 | from £14.95 |
16 tablets | from £81.45 | from £17.19 |
32 tablets | from £159.95 | from £32.49 |
64 tablets | from £309.95 | from £45.50 |
All of our medication and condition content is written by UK qualified pharmacists and doctors.
Authored: 22/05/2022
Reviewed: 20/03/2025
How Viagra Works Read about how Viagra treats erectile dysfunction |
How Long Does Viagra Take to Work? Learn how long Viagra takes to be effective |
Viagra and Alcohol Can Viagra be taken with alcohol? Find out here |
First-Time Viagra Use What to expect when taking Viagra for the first time |
Over-the-Counter Viagra Availability of Viagra over the counter |
Side Effects of Viagra Read the complete list of Viagra side effects |
Cialis vs. Viagra How Cialis compares to Viagra for ED |
Viagra vs. Kamagra Comparison of Viagra and Kamagra |
Sildenafil | Viagra | Tadalafil | Cialis | Vardenafil | Levitra | Spedra | |
Active Ingredient | Sildenafil | Sildenafil | Tadalafil | Tadalafil | Vardenafil | Vardenafil | Avanafil |
Time to Take Effect | 30-60 mins | 30-60 mins | 15-45 mins | 15-45 mins | 30-60 mins | 30-60 mins | 15-30 mins |
Duration of Action | 4-6 hours | 4-6 hours | 24-36 hours | 24-36 hours | 4-6 hours | 4-6 hours | 4-6 hours |
Unique Feature | Same active ingredient as Viagra | Most well known | Same active ingredient as Cialis | Longest Acting | Used for diabetics | Used for diabetics | Quickest Acting |
Price Per Tablet | From 78p | From £4.84 | From 67p | From £2.26 | From £2.74 | From £2.97 | From £2.97 |
Before taking Viagra or any medication, it is important to read the Patient Information Leaflet.
There is a potentially lethal reaction with nicorandil or other nitrate medications. If you use medicines for angina such as isosorbide mononitrate or GTN spray, you are unable to use Viagra. If taken together, blood pressure may decrease dramatically and lead to a heart attack.
Speak to your GP for further advice.
Alpha-blocking medicines for high blood pressure, such as tamsulosin or alfuzosin, interact with Viagra. They can cause a significant decrease in blood pressure. You should see your GP, because the 25mg strength may be most suitable for a patient taking alpha-blockers.
You should leave a minimum six-hour period between taking Viagra and an alpha-blocker. If you're not sure, speak to your GP for medical advice.