Erectile Dysfunction (ED)

Dr Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 09 Oct 2019

A guide to the symptoms, causes, diagnosis, and treatment of ED

Man researching erectile dysfunction treatment on Zava's website

Key ED facts

  • Very common: affects 1 in 4 men aged 18 to 75
  • Easy to diagnose
  • Often a symptom of another condition
  • 3 main ways to treat


Erectile dysfunction (ED), or impotence, is the medical name for not being able to get hard enough, or keep an erection long enough, to have sex.

It’s normal to occasionally have problems getting and keeping erections and to sometimes lose them. But if you find this happens at least half of the time you’re having sex, you may be experiencing ED.

ED can happen at any age, but it is more common in men over 40. Roughly half of all men between the ages of 40 and 70 will experience ED.


With erectile dysfunction (ED), you may have one or more of the following symptoms. If you have ED, you'd notice these more than half of the time you're having sex:

  • not being able to get an erection at all
  • a low sex drive
  • problems getting a full erection
  • problems keeping an erection


It’s not always easy to work out exactly what is causing erectile dysfunction (ED). It can be a symptom of a physical or emotional condition. It might be caused by your lifestyle. And it can also be a side effect of certain types of medication. ED can also be caused by a combination of these factors.

You’re more likely to get ED as you get older, but it's not linked directly to age, and can affect people at any stage in their life. As our bodies age, we’re more likely to develop physical conditions, which is why ED is more common in older people.

Man considering causes of his erectile dysfunction

Physical conditions

Blood flow to the penis

When you have an erection, extra blood flows into your penis. If you have any conditions that affect blood flow, this can cause ED. These conditions include:

Problems with your hormones

The amount of certain hormones your body is releasing can cause ED.

Testosterone is a hormone that affects your sex drive. If you have a low testosterone level that lowers your sex drive, it can be hard to get or keep erections.

The thyroid (a gland in your neck) releases hormones that control your metabolism (the way your body turns what you eat and drink into energy). It’s not completely clear why, but when the thyroid releases less or more hormones than usual, this can also cause ED.

Problems with your nervous system

Your nervous system is made up of your brain, nerves and spinal cord. When you get turned on, your brain sends signals to your nerves to relax the vessels in your penis and allow more blood to flow in. Conditions that affect the nervous system can cause ED. These include:

Conditions that affect your penis

If you have any conditions that have changed the structure of the penis or the surrounding area, this can cause ED. Examples include:

Emotional conditions

A large part of getting an erection is the feeling of being turned on, which sends signals from your brain to start changes in your body.

Even small emotional changes can have an effect on being able to get and keep an erection. These emotional conditions include:

  • relationship problems
  • stress
  • anxiety
  • depression
  • low self-esteem
  • being or having been abused


The things we do in everyday life are not necessarily direct causes of ED, but they can make physical and emotional changes that create or add to the problem. In some cases these changes can turn into more serious conditions.


Smoking has a direct effect on the blood flow around your body which makes it harder to get or keep an erection.

Smoking over a period of time can damage the lining of your blood vessels and change the way they work. It’s also linked to more serious physical conditions, like heart disease and stroke.

Drinking alcohol and taking drugs

Like cigarettes, alcohol makes it harder for blood to flow around your body. It’s also a ‘depressant’ which means that it slows down the function of your nervous system.

Alcohol can affect the way you’re feeling, lower your mood, and stop you wanting to have sex, especially if you’ve been drinking above the recommended limits over a long period of time.

Taking drugs, like ecstasy and cocaine, can have a similar effect on your body and mental health.

Being overweight

If you’re above a healthy weight for your size, it can lead to conditions that change your blood flow and affect your nervous system. Being overweight has also been linked to lower testosterone levels.

Being heavier than you’d like can also cause emotional problems, like low self-esteem.

Medications you're taking

ED can be a side effect of certain types of medication. These include:

  • antidepressants
  • antihistamine
  • high blood pressure medication


Erectile dysfunction (ED) is not difficult to diagnose, but it can sometimes be hard to work out the exact cause. A diagnosis that helps you understand what is causing your ED will give you the best chance of treating it effectively.

Getting a quick online diagnosis for erectile dysfunction from Zava

Online diagnosis

If you think you have ED and believe medical treatment would be right for you, our doctors can prescribe a number of medications via an online questionnaire. Our pharmacy can then prepare and send the medication to you. Just choose the medication that you feel would be right, click Start Order, and fill in the four-minute questionnaire.

View ED medication
View ED medication

If you’re not sure whether you have ED, or you'd like some help choosing your medication, our doctors can do a free ED assessment and suggest the best treatment for you. Just click Start free assessment below. You can fill in the four-minute questionnaire at any time, and our doctors will get back to you within 5 working hours (9am to 4pm Monday to Friday).

Start free assessment
Start free assessment

GP diagnosis

When you speak to your GP about ED, they’re likely to ask you questions about your lifestyle, physical health, mental health, and about any medications you’re taking.

In some cases, they may look at your penis and check your prostate (a gland between the bladder and the penis), and might suggest you take further tests.

Your GP may refer you to a specialist (a urologist) if the cause of the problem is not obvious.

Pharmacist diagnosis

A pharmacist can give you advice on ED, and in some cases may offer you over-the-counter medication. Most pharmacies have private consultation rooms so you do not have to talk about your concerns in public.


There are three main ways to treat erectile dysfunction (ED). How you decide to treat it will depend on what is causing the condition.

Man getting erectile dysfunction treatment online with Zava

Medical treatment


The most common medication for ED is a drug called sildenafil, sold under the brand name Viagra. It works by allowing more blood to flow into your penis.

Taking this type of medication does not have a direct effect on your sex drive. You’ll still need stimulation to get an erection when you’re taking it.

There are also similar types of medication that work like Viagra. These include Cialis, Tadalafil, Levitra, and Spedra.

View ED medication
View ED medication

Vacuum penis pumps

Vacuum penis pumps use air pressure to get blood into the penis. Once enough blood is there, a ring is placed at the base to stop the blood from flowing away too quickly.

View vacuum penis pumps
View vacuum penis pumps


If your ED is caused by low sex drive linked to your testosterone levels, it’s possible to get treatment to raise the amount of the hormone in your body.

View testosterone test and treatment
View testosterone test and treatment


Alprostadil is a lab-made hormone that allows more blood to flow into the penis. It's usually injected into the base of the penis, put into the penis in a small pellet (suppository), or rubbed onto the skin as a cream.

Penile implants

Penile implants are devices placed inside the penis. There are two different types: one which inflates and one which makes the penis firm at all times. For both types you need to have surgery to put them in place.

Talking therapy

If your ED is caused by emotional changes or mental-health problems, talking to someone about how you feel can help. It may be useful to talk to a counsellor who specialises in sex therapy.

A doctor may refer you for therapy or you can get in touch with a therapist yourself. It’s a good idea to choose a therapist who’s registered with the British Association of Counselling and Psychotherapy or the UK Council of Psychotherapy.

Lifestyle changes

There are a number of actions you can take to make sure that your blood is flowing well around your body (which can help to avoid ED). These include:

Pelvic floor exercises

Doing pelvic floor exercises will help you build up the muscles around the penis. This will improve the blood flow to the area. It can take a few months of doing regular pelvic floor exercises to see any changes.

Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.

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Last reviewed: 09 Oct 2019

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