Erectile dysfunction

Erectile dysfunction is when men are unable to get or keep an erection suitable for sex. Dr Fox provides advice and confidential treatment for erectile dysfunction posted direct.

Read medical information and answer medical questions to buy treatment online.

Medical information

Erectile dysfunction (ED) is common. It is not usually caused by low hormone levels. Most men with erectile dysfunction are in reasonable health, although erectile dysfunction may be a symptom of poor circulation or early diabetes. Erectile dysfunction is more common in smokers and men who are overweight. Some medicines including herbal medicines can contribute to ED. Some men with ED have low testosterone levels. Cycling more than 3 hours a day can cause ED.

All men with ED should tell their GPs about it.

ED treatments

Over the last decade medications have revolutionised the treatment of erectile dysfunction. These medications work by enhancing the natural reaction to stimulation, opening up the blood flow needed for erections. Other treatments for ED include topical applications, injections into the penis, surgical devices and counselling.

Types of treatment

Seven different medications are available to buy online from Dr Fox:

Each tablet has a different duration of action and side effects – see tablet differences below.

No combination of Viagra/sildenafil, Cialis/tadalafil, Levitra/vardenafil, Spedra or other ED treatment should be used at the same time – a break of up to 24 hours (36 hours for Cialis/tadalafil) should be left.

Investigating erectile dysfunction

You should always tell your regular doctor if you are having problems with erections.

Erectile dysfunction can be a symptom of conditions such as diabetes, high blood pressure, high cholesterol or narrowing of the arteries. Some simple tests may be required. A face-to-face assessment with a doctor is particularly important if symptoms develop over a period of weeks or months, or even suddenly, without an emotional event to set them off. Erectile dysfunction can be a complication of previous operations or a side effect of some prescribed medication.

Lifestyle and risk factors

Improving lifestyle factors such as diet, exercise, smoking, excessive alcohol, and maintaining an active lifestyle has shown improvement in ED in men of all ages. Apart from the general benefits of a healthy lifestyle, studies show improvement in erectile dysfunction symptoms and a reduced need for tablets. ED also shares risk factors with a range of other medical conditions including diabetes, heart disease, and circulatory problems, all of which are also likely to benefit from lifestyle modification.

Starting treatment

It is best to start with a lower strength tablet and build up as needed (see how to start treatment). One type of tablet sometimes works better than another. You may like to try out different tablets to see which ones suit you best.

Sexual stimulation is required for tablets to work. Without it tablets will have no effect.

You can request more than one type of tablet at a time. A first trial of treatment starts at £6.90.


Erectile dysfunction can be distressing and lead to relationship difficulties, anxiety, and depression. Your regular doctor may recommend counselling. This may help resolve the cause of erectile dysfunction. In some cases a problem of performance anxiety can be overcome by breaking the cycle of failure with tablet treatments.

Buy treatment

Dr Fox supplies treatment for erectile dysfunction (impotence) on prescription – you are required to answer a short medical questionnaire before your order can be completed.

Tablet differences

Compare erectile dysfunction tablets
Sildenafil Tadalafil Vardenafil Avanafil
Brand names Viagra, Viagra Connect Cialis Levitra Spedra
Available generically Yes Yes Yes No
Starting dose 50mg 10mg 10mg 100mg
Time taken to start working 30-60 minutes 30-60 minutes (2.5mg and 5mg tablets can be taken daily) 25-60 minutes – faster for orodispersible tablets 15-30 mins on empty stomach, 1.5 hours on full stomach
How long effects last 4 hours 36 hours 4-5 hours 4 hours
Warnings and cautions
Warning Sildenafil Tadalafil Vardenafil Avanafil
Do not take Allergic to ingredients, low or high blood pressure, severe heart or liver problems, loss of vision due to NAION, recent stroke or heart attack
Rare inherited eye diseases Kidney dialysis, rare inherited eye diseases Liver or kidney problems, rare inherited eye diseases
Exclusions - talk to your doctor first Sickle cell anaemia, multiple myeloma, leukaemia, deformity of the penis, problems with your heart, stomach ulcer or bleeding problems
Drug interactions Any nitrate-based medication, usually to treat angina (important); 'poppers'; nitric oxide donors, medicines for HIV, AIDS, or fungal infections; riociguat; alpha-blockers; other ED medicines
Common side effects (% occurrence)
Adverse event Sildenafil Tadalafil Vardenafil Avanafil
Headache 12.8% 14.5% 16% 9.3%
Flushing 10.4% 4.1% 12% 3.7%
Dyspepsia (indigestion) 4.6% 12.3% 4% uncommon
Nasal congestion 1.1% 4.3% 10% 1.9%
Dizziness 1.2% 2.3% 2% 0.6%
Abnormal vision 1.9% < 2% none
Back pain 6.5% < 2%
Myalgia (muscle pains) 5.7% < 2%
Medical emergencies (very rare)
Urgent medical attention required Sudden decrease or loss of vision, Priapism (painful erection lasting 2 hours or more), allergic reaction, chest pains, heart attack

Notes: Sexual stimulation is required before erection will take place. See the patient information leaflet links above for full details of cautions and interactions. You may get no side effects. If side effects are severe stop the medication and see your doctor.

Dr Tony Steele

Authored 18 February 2010 by Dr Tony Steele
Last updated 16 August 2019

Reviewed by Dr B. Babor, Dr A. Wood, Dr P. Hunt
Last reviewed 19 June 2019


Treatment available

photo of Viagra 50mg pack

Viagra (sildenafil)

25mg, 50mg, 100mg from £5 per tablet

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photo of 25mg, 50mg, 100mg packs of Sildenafil

Sildenafil (generic Viagra)

25mg, 50mg, 100mg from 97p per tablet

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photo of 10mg pack of Cialis

Cialis (tadalafil)

2.5mg, 5mg, 10mg, 20mg from £2.29 per tablet

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photo 10mg pack of Tadalafil

Tadalafil (generic Cialis)

2.5mg, 5mg, 10mg, 20mg from 81p per tablet

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photo 20mg pack of Levitra

Levitra (vardenafil)

5mg, 10mg, 20mg from £3.75 per tablet

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photo of 100mg pack of Spedra

Spedra (avanafil)

50mg, 100mg, 200mg from £3.10 per tablet

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Prices of ED treatment from Dr Fox (in stock)
Quantity of tablets x4 x8 x16 x32 x64
Sildenafil 25mg £6.90 £13.70 £24.80 £43.20 £62.00
Sildenafil 50mg £8.90 £15.60 £26.80 £51.00 £84.00
Sildenafil 100mg £9.80 £16.20 £28.40 £54.00 n/a
Viagra 25mg £24.20 £44.30 £82.00 n/a n/a
Viagra Connect 50mg £19.99 £34.99 n/a n/a n/a
Viagra 50mg £29.40 £59.50 £112.60 n/a n/a
Viagra 100mg £33.80 £64.45 £124.40 n/a n/a
Tadalafil 10mg £11.50 £20.80 £36.80 n/a n/a
Tadalafil 20mg £12.50 £22.50 £39.40 n/a n/a
Cialis 10mg £35.40 £67.50 £129.60 n/a n/a
Cialis 20mg £36.20 £68.80 £133.20 n/a n/a
Vardenafil 10mg £19.90 £34.20 £56.80 n/a n/a
Vardenafil 20mg £25.50 £48.00 £84.00 n/a n/a
Levitra 10mg £24.00 £43.00 £75.00 n/a n/a
Levitra 20mg £28.00 £53.00 £105.00 n/a n/a
Levitra Orodispersible 10mg £29.00 £51.00 n/a n/a n/a
Spedra 50mg £16.50 £28.00 £49.50 n/a n/a
Spedra 100mg £19.50 £37.00 £68.00 n/a n/a
Spedra 200mg £29.50 £54.50 £98.00 n/a n/a
Medicine 28 tablets 56 tablets
Daily Tadalafil 2.5mg £22.50 £41.10
Daily Tadalafil 5mg £24.10 £46.40
Daily Cialis 2.5mg £66.50 £128.30
Daily Cialis 5mg £67.60 £132.20

Price match guaranteePrice match guarantee
Prescription issued online - small prescription fee per order.

Compare prices: Dr Fox prices are 25%-50% lower cost than other online clinics.

Prescription fees

Dr Fox supplies medicine on prescription and charges a small prescription fee based on the order value of each prescription.

Prescriptions are issued by our doctors online and sent electronically to our pharmacy.

If you have your own private or NHS paper prescription please post to our pharmacy (details).

Dr Fox prices are 25%–50% lower than other UK online clinics.

Order value Prescription fee
up to £10 £1.00
up to £20 £2.00
up to £40 £3.00
over £40 £4.00

Compare prices of Cialis/tadalafil, Levitra, and Spedra.

Compare prices of Viagra/sildenafil tablets from UK online clinics (28 August 2018) - qualifying notes
*Dr Fox adds a small prescription fee not included in table above.
  1. The prices shown are listed by the online clinics named after a customer first enters consultation information and is offered prescriptions. It is possible these clinics may have special offers or lower prices for repeat supplies.
  2. Prices may change and are, to the best of our knowledge, accurate on the date stated. All products in stock and new condition.
  3. Dr Fox does NOT claim to provide a superior service to any of the online clinics listed. All the clinics listed, as far as we can tell, comply with all regulation and, as far as we can tell, operate to high ethical standards.
  4. Dr Fox adds a small prescription fee not included in the table (between £1 and £4 depending on value of the order).
  5. To amend the information in this table please contact us
  6. The prices listed in the table do not identify the cost of prescription medicine as online clinics charge a single fee to cover services which includes advice, consultations, prescriptions, and dispensing and supply of treatments.
  7. Where services include free delivery this is using the slowest delivery option available. Dr Fox uses Royal Mail Tracked 24.
Generic/Branded Dr Fox* Express Pharmacy Zavamed Pharmacy 2U Med Express
Sildenafil 25mg x 4 £6.90 £19.99 £15.00 £15.00 £9.99
Sildenafil 25mg x 8 £13.70 £29.99 £25.00 £23.00 £19.99
Sildenafil 25mg x 16 £24.80 £49.99 £45.00 £40.00 £39.99
Sildenafil 25mg x 32 £43.20 n/a n/a £60.00 £79.99
Sildenafil 50mg x 4 £8.90 £19.99 £20.00 £23.00 £17.99
Sildenafil 50mg x 8 £15.60 £29.99 £30.00 £38.00 £29.99
Sildenafil 50mg x 16 £26.80 £49.99 £50.00 £60.00 £49.99
Sildenafil 50mg x 32 £51.00 n/a n/a £86.00 £89.99
Sildenafil 100mg x 4 £9.80 £19.99 £25.00 £27.00 £19.99
Sildenafil 100mg x 8 £16.20 £29.99 £30.00 £56.00 £34.99
Sildenafil 100mg x 16 £28.40 £49.99 £50.00 £75.00 £59.99
Sildenafil 100mg x 32 £54.00 n/a n/a £130.00 £99.99
Viagra 25mg x 4 £24.20 £44.99 £32.00 £32.50 £29.99
Viagra 25mg x 8 £44.30 £69.99 £48.00 £50.00 £59.99
Viagra 25mg x 16 £82.00 £129.99 £82.00 £95.00 £119.99
Viagra 50mg x 4 £29.40 £44.99 £36.00 £30.00 £34.99
Viagra 50mg x 8 £59.50 £76.99 £58.00 £50.00 £69.99
Viagra 50mg x 16 £112.60 £149.99 £100.00 £85.00 £139.99
Viagra 100mg x 4 £33.80 £46.99 £39.00 £40.00 £34.99
Viagra 100mg x 8 £64.45 £79.99 £62.00 £60.00 £69.99
Viagra 100mg x 16 £124.50 £159.99 £109.00 £95.00 £139.99
UK Delivery £2.90 £2.95 included £3.45 £2.90

Delivery charges

UK delivery only: £2.90 per consultation via Royal Mail 24 Signed For (1-3 working days with tracking).

Parcel forwarding services are not permitted. Use only UK home or work delivery address.

Returns and refunds - unwanted items can be returned within 14 working days for a full refund.

  1. Medical questions
  2. Choose treatment
  3. Complete order

Answer medical questions to order(erectile dysfunction)

Men only

Have you read the erectile dysfunction medical information?

Please read the medical information.
See also starting treatment for the first time.

Do you sometimes or always have difficulty getting and keeping an erection?

Have you had difficulties with erections for more than a year?

Are your erections sometimes fine?

E.g. when waking in the morning, during masturbation or in some erotic situations.

Is your blood pressure high (over 150/90)?

You must have had a blood pressure check within the last year and know the result. Doctors, nurses, and some pharmacists can check blood pressure. Answer 'Yes' if either figure is high, 150 or 90. A blood pressure measurement whilst taking blood pressure tablets qualifies.

Do you have low blood pressure?

This means any of the following:

  • Low blood pressure requiring investigation
  • Low blood pressure requiring treatment
  • Being prone to faint or feel light-headed for more than a few seconds when standing up quickly or standing for long periods

Are you over weight?

Use this BMI (Body Mass Index) calculator and answer 'yes' if the result is over 30.

Do you smoke or drink more than 21 units of alcohol per week?

Have you been diagnosed with any of the following?

  • Allergy or reaction to previous impotence treatments
  • Heart disease including heart attack within 6 weeks or angina (heart pain on exertion)
  • History of stroke or mini stroke (transient ischaemic attack)
  • History of vision problems due to poor circulation
  • Family history of the degenerative eye disease, including retinitis pigmentosa (rare)
  • Serious kidney/renal or liver disease
  • Deformity or angulation of the penis (Peyronie’s disease)
  • Sickle cell disease or leukaemia or multiple myeloma
  • A bleeding disorder (such as Haemophilia)
  • Active stomach ulcers (also known as peptic ulcer or gastric ulcer)

Are you taking any of the following?

  • Existing ED treatment apart from Viagra/sildenafil, Cialis/tadalafil, Levitra, or Spedra
  • Nitrates for angina or heart failure, includes glyceryl trinitrate, isosorbide mononitrate, isosorbide dinitrate, GTN spray or gel, or nicorandil - serious reaction possible
  • Ritonavir or Indinavir or medicine for HIV
  • Riociguat for high blood pressure in the lungs
  • Ketoconazole or itraconazole or other anti-fungal medication
  • Any recreational drugs, particularly amyl nitrate (Poppers) - serious reaction possible
  • Alpha-blockers (sometimes used to treat high blood pressure or prostate enlargement) includes alfuzosin, doxazosin, indoramin, prazosin, tamsulosin, terazosin

Have you been advised to avoid vigorous exercise?

E.g. severe heart failure or unstable angina.

Are you aware if you have a continuous erection for 4 hours or more you should seek immediate medical advice?

This is unlikely to happen and is rare. If it occurs seek medical advice straight away to prevent permanent damage.

Are you aware you should not take any combination of Viagra/sildenafil, Cialis/tadalafil, Levitra/vardenafil or Spedra, or use any other ED treatment, at the same time?

  • A break of up to 24 hours (36 hours for Cialis/tadalafil) should be left.
  • Also do NOT exceed the prescribed dose.

Do you have any further medical information or questions?

Is there anything you do not understand or do you need further help?

Do all the following apply to you?

The order process

Answer short medical questionnaire

Choose treatment, register, and pay

Doctor issues prescription online

Medicine posted direct from pharmacy

Recent reviews

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