Erectile Dysfunction (ED): Causes, Tests and Treatment

"It just won't get hard" is something many men experience but few dare to say out loud. For some it starts with no longer waking up with an erection. For others it only happens with a partner, or they can get hard but it doesn't last. I want to say first that this does not make anyone less of a man, and in most cases it can get better once we find the cause.

What is ED?

Erectile dysfunction (ED) means persistently being unable to get an erection, or to get one firm enough, or to keep it long enough for satisfying sex (usually for more than 3 months).

Occasionally not getting hard when you are exhausted, have drunk a lot or are very stressed is not necessarily ED. More than half of all men experience this at least once in their lives.

If you want a clearer picture, try assessing yourself with the IIEF-5 questionnaire or the Erection Hardness Score.

Common myths

• "ED only happens to old men." Not true. Age does raise the risk, but diabetes, high blood pressure, high cholesterol, smoking, alcohol and stress can cause ED at any age.
• "Just take an erection pill every time." The tablets work well, but if the underlying cause, such as high blood sugar or high blood pressure, is ignored, the problem tends to come back and the other disease quietly progresses.
• "A testosterone injection will cure it." Not for everyone. Hormones only help men whose testosterone is genuinely low, and the TRAVERSE study (2023) found that testosterone in men with low levels improved desire and sexual activity, but did not clearly improve erections compared with placebo.
• "Seeing a doctor is embarrassing." Avoiding it only lets the problem drag on and affect your relationship.

The three main groups of causes

In real life the cause is usually a mix of more than one group.

1. Physical causes

• Blood vessels: the most common cause in middle age, from diabetes, high blood pressure, high cholesterol, smoking and belly fat
• Nerves: for example long-standing diabetes, pelvic surgery or spinal cord injury
• Some medicines: certain antidepressants, some blood pressure medicines and anti-hormone treatments
• Recreational drugs and alcohol

Read more in What causes erection problems, and vascular ED.

2. Psychological causes

Stress about work or money, conflict with a partner, worry about not getting hard (performance anxiety) and depression all stop the nerves that control erections from working fully. When a man still gets good morning erections or erections during masturbation, but not with a partner, psychological factors are usually involved.

3. Hormonal causes

Low testosterone tends to reduce desire more than it directly causes ED. It often comes with tiredness, poor sleep, loss of muscle and more belly fat. See Symptoms of low testosterone. Thyroid problems and abnormal prolactin levels can also play a part.

Premature ejaculation and ED can feed each other

Many men have both. Worried about losing the erection, they rush; rushing leads to ejaculating quickly; afterwards the mood drops, a second round isn't possible, and the worry grows. Treatment needs to address both at the same time. Read more about premature ejaculation (PE).

ED

Physical

Body

• Blood vessels (most common in middle age)
• Nerves
• Some medicines
• Drugs, alcohol

Psychological

Mind

• Stress: work, money
• Conflict with partner
• Fear of not getting hard
• Depression

Hormonal

Hormones

• Low testosterone (reduced desire)
• Thyroid disorders
• Prolactin disorders

Why diabetes causes ED

Blood sugar that stays high for a long time damages the inner lining of the blood vessels (the endothelium), so it produces less nitric oxide, the key chemical messenger for erections. It also damages small nerves. Men with diabetes are therefore several times more likely to have ED than other men, and tend to develop it earlier. Good blood sugar control is part of the treatment.

How ED is diagnosed

1. Medical history: how long, what exactly happens, morning erections, medicines, stress and your relationship
2. Physical examination: blood pressure, pulse, waist size, penis and testicles
3. Blood tests: blood sugar (FBS/HbA1c), cholesterol, and a morning testosterone level when low testosterone is suspected
4. Cardiovascular risk assessment following the Princeton IV recommendations (2024), because ED can come years before coronary heart disease
5. Special tests, such as ultrasound of the penile blood vessels, only for selected men

1. 1HistoryDuration, morning erections, medicines, stress, relationship
2. 2ExaminationBlood pressure, pulse, waist, penis and testicles
3. 3Blood testsGlucose, lipids, morning testosterone if suspected
4. 4Heart checkED can appear years before heart disease
5. 5Special testsE.g. vascular ultrasound, only in some men

Heart-risk assessment follows the Princeton IV guidance (2024).

Treatment options

The latest AUA and EAU guidelines focus on treatment that matches the goals of the patient and their partner, with several options that can be combined.

• Lifestyle changes: aerobic exercise, weight loss, stopping smoking, cutting down on alcohol and getting enough sleep genuinely help, especially in vascular ED.
• PDE5 inhibitors such as sildenafil and tadalafil are the main treatment and work well for most men. See how they differ in Tadalafil vs sildenafil.
• Hormone treatment only for men with confirmed low testosterone. Read What is TRT and who is it for?
• Sex therapy and couples therapy, for example Sensate Focus, reduce anxiety and rebuild intimacy.
• Other options, such as penile injections, vacuum devices or a penile implant, for men in whom tablets don't work. "Restorative" treatments such as low-intensity shockwave therapy or PRP still have limited evidence.

When to see a doctor

• Erection difficulties lasting more than 3 months, or starting suddenly without an obvious reason
• You have a chronic condition such as diabetes, high blood pressure or heart disease, or take several medicines
• Your penis has an unusual bend, a lump or pain
• Go to hospital immediately if an erection lasts more than 4 hours, or if you have chest pain or tightness during or after sex (in Thailand call 1669)

At Dr. Kris Clinic we look after ED as a whole: assessing your symptoms, checking blood tests and hormones, looking at other conditions, planning safe use of medicine, and offering relationship counselling. You can see us at the clinic in Surat Thani or online, and consultations in English are available. There is no judgement here, so feel free to tell me everything.