• Customer Service Team available now: Mon-Fri 8:00-17:00
  • Private & confidential service
  • Genuine medication
  • All-inclusive service - No hidden fees
  • Next day delivery
Home / Erectile Dysfunction / Sildenafil


How to buy Sildenafil online in the UK

  • Box contains 8 Sildenafil Teva 50mg film-coated tablets
  • Pack contains 8 Sildenafil Teva 50mg film-coated tablets with a blister strip
4.5 57 Patient reviews review
Prices of Sildenafil (Generic)
4 tablets (£8.99)

Prices include next-day delivery and prescription

4 tablets £8.99
8 tablets £16.99 Save £1
12 tablets £23.99 Save £3
16 tablets £28.99 Save £7
32 tablets £49.99 Save £22

Select your treatment after the consultation:

Back to Start Consultation
Order today for FREE next-day delivery
Free next-day delivery
Subscribe & Save: Get 10% off with repeat prescriptions

How to buy Sildenafil online?

To buy any medication in the UK, you will require a prescription. Traditionally done through booking a doctor's appointment face-to-face, you can now order Sildenafil online when completing a consultation. At OnlineClinic, this is free with no obligation attached and can be completed within minutes. Sent to one of our doctors, Sildenafil can be ordered online today and delivered as early as tomorrow. All our delivery and packaging options are 100% confidential, so you can get your medication delivered wherever with complete peace of mind.

What is Sildenafil?

Sildenafil is a proven, effective medication to treat erectile dysfunction (ED) that you can buy at OnlineClinic. It is also the active ingredient in the tablets, as well as in the branded version of the ED medication Viagra. It has been proven to work within half an hour of taking the pill, and can last up to five hours.

To make the most out of your ED medication, you can adopt a number of tactics, such as low-fat meals and cutting back on alcohol. We will explain how to take Sildenafil, and how to get the most out of it below.

Short facts about Sildenafil
How to take

Only take when needed about 30-60 minutes before sex. It is advised to take Sildenafil with water on an empty stomach.

How it works

Sildenafil is a phosphodiesterase type 5 (PDE-5) inhibitor that works by encouraging chemical messages released by the brain, and widens the blood vessels in the penis to cause an erection.


Proven to last up to five hours and effective within an hour of taking the first tablet for the vast majority of users.


Available to buy in three dosages including 25mg, 50mg and 100mg. 50mg is the recommended dosage.

Side effects

Side effects of Sildenafil include flushing (especially on the face), stomach ache, cold symptoms and muscle pain. These are uncommon, or vanish quickly, as it's a needs-be medication.

How does Sildenafil work?

Sildenafil is medically known as a phosphodiesterase type 5 (PDE-5) inhibitor and is the generic unbranded medication for ED. Using the active ingredient of the same name, Sildenafil prevents the chemical 'phosphodiesterase type 5' from functioning to allow more blood to enter the penis through relaxing the blood vessels in the area.

As Sildenafil interacts with chemical messengers, known as cyclic GMP, this means you will need to be aroused within the first five hours of taking the tablet to experience an erection. Taking ED medication like Sildenafil doesn't mean you will be erect for five hours continually.

How to take Sildenafil?

As Sildenafil is taken on a needs-be basis, you don't need to remember a certain time of the day or week. Instructions are easy to remember and are as follows:

  • Take one tablet, swallowed whole with a sip of water
  • Do not take more than one tablet within 24 hours
  • Effectiveness can start in as early as half an hour
  • On average, Sildenafil will work between 30-60 minutes
  • Sildenafil will remain effective for up to five hours

ED medication is simple to take, with quick reactions, however, there are some scenarios that slow down effectiveness:

  • Taken on an empty stomach, or keeping meals small and light in fat means the pill is absorbed into the system quicker
  • Alcohol can reduce effectiveness
  • Grapefruit can interact with ED medication, provoking side effects


There are three dosages of Sildenafil available (25mg, 50mg and 100mg) and you can buy all three here at OnlineClinic. 50mg is the middle ground and recommended dosage, proving to supply maximum success with minimal side effects. If you find the 50mg is ineffective, you can buy the higher dosage of 100mg. On the other end of the spectrum, if you have experienced side effects with the 50mg dose, you may be prescribed 25mg.

Side effects and precautions

As Sildenafil is only taken when needed, there is a very small chance that you will experience side effects, however if you do, these are often temporary and highly manageable; aches and muscle pain, diarrhoea, flushing, headaches, stomach ache (indigestion), cold symptoms or trouble sleeping. The full list of possible side effects can be found in the medication patient leaflet at the right of this page. If you are experiencing particularly severe side effects, it is advised to stop taking the medication and contact your doctor.

There are also some precautions to take when using Sildenafil for a minority of users. It goes without saying that women should not use any erectile dysfunction medication. Some other precautions include the following:

  • Decreased kidney function
  • Decreased liver function
  • In elderly people
  • Cardiovascular disease

If you have experienced any of the following, you may not be prescribed Sildenafil, or you need to use in caution:

  • Heart failure
  • Stroke
  • Low blood pressure

There are other precautions that should be considered when taking ED medication. When completing a consultation, any medical history with you or direct family should be disclosed so our doctors can recommend alternative treatment, or the correct dosage.

Note: Decisions about treatment are for both the prescriber and the person to jointly consider during the consultation. However, the final decision will always be the prescriber’s.

Sildenafil information
Product name Sildenafil
Active ingredient(s) Sildenafil
Administration Oral
Presentation Tablets
Available dosage25mg, 50mg, 100mg
Exemption Subject to medical prescription
Application Men over 18 with impotence/erectile dysfunction
Usage Take 1 tablet 30-60 minutes before sexual intercourse
Lowest price £8.99
Trustpilot rating 4.5/5
Trustpilot reviews 57
Availability In stock
Description Sildenafil is one of the most popular and effective erectile dysfunction treatments available
Drug class PDE5 inhibitor
Alcohol consumption Alcohol may reduce the effects of impotence medication
When breastfeeding Not applicable
When pregnant Not applicable
Fill out a short
medical form
Doctor issues
Medication sent
from pharmacy
Service ratings
Rating Excellent 4.9 2,189 patients have rated our service
Product ratings
Excellent 4.5 57 patients have reviewed Sildenafil
Our Patients Love
  • Reachable and friendly customer serviceCustomer service online now: Mon-Fri 08:00 - 17:00
  • All-inclusive service - No hidden feesAll prices include shipping & prescription
  • Next day deliveryFor all orders before 16:30

Current reviews for the treatment Sildenafil

Rated with 4.5 based on 57 Independent customer reviews.

  • Excellent Product Review: real good 02 May
  • Great Product Review: OK received the next day. 04 Dec
  • Excellent Product Review: Effective in every way 02 Jul
  • Excellent Product Review: Great, very pleased. 24 Jun
  • Excellent Product Review: Hi One Clinic is a great company to deal with I order and then stipulate what da... 12 Oct