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    Can a blood test detect erectile dysfunction?

    On this page
    1. Why does high cholesterol cause ED? 
    2. Why does diabetes cause ED? 
    3. Low testosterone and ED 
    4. LloydsPharmacy Online Doctor’s healthy lifestyle hub 

    Reviewed by Dr Bhavini Shah

    To get and maintain an erection, you need a healthy blood supply, a healthy nervous system and sexual desire. Physiological and psychological factors can disrupt these and cause erectile dysfunction (ED).  

    Because many factors can cause ED, it can sometimes be difficult to get to the root cause of what’s causing it. A blood test often helps us to understand the cause of ED as it reports on risk factors associated with ED, such as high cholesterol, diabetes, and low levels of testosterone. A blood test can be done privately, at home, or by your GP if they think you need one.  

    Blood Test and ED

    Why does high cholesterol cause ED? 

    Cholesterol is a type of fat found in the blood. It is made in the liver and is also found in some of the foods we eat, such as red meat. Cholesterol is needed to keep the cells in our bodies healthy, but too much of it causes problems such as an increased risk of stroke, heart diseases, and the narrowing of blood vessels.  

    There is a link between high levels of cholesterol and ED. This is because too much cholesterol restricts blood flow through the arteries which can affect to blood supply to the penis.  

    High cholesterol can be reversed by: 

    • Eating less fatty food  
    • Stopping smoking  
    • Cutting down on alcohol  
    • Exercising more   

    A finger-prick cholesterol blood test can be done at home. A small sample is collected using a lancet and the sample is sent to a lab. If your cholesterol levels are abnormal, your healthcare provider will talk to you about how it can be brought down through lifestyle changes or medication.  

    Why does diabetes cause ED? 

    Diabetes is a condition which causes our blood sugar (glucose) levels to become too high. High levels of glucose in the blood can cause damaged blood vessels, including those supplying the penis. This can lead to erectile dysfunction

    A home blood test will help you understand your risk of developing diabetes or if you already have it. The test will check for glycated haemoglobin (HbA1c). HbA1c is made when glucose sticks to red blood cells.  By measuring glycated haemoglobin (HbA1c), clinicians can get an overall picture of what your average blood sugar levels have been over a period of weeks/months. 

    It may be possible to put type two diabetes into remission through losing weight and eating healthily.  This will also help your ED if it’s linked to diabetes.  

    Low testosterone and ED 

    As we age, our testosterone levels naturally decrease – but not by a huge amount. Between the ages of 30 and 40, testosterone will decline normally at a rate of less than 2% a year, but most men will still have the testosterone they need to enjoy a healthy sex life.  

    Other causes of low testosterone can be broken down into: 

    • Primary testosterone deficiency – low testosterone caused by the failure of the testicles to make enough testosterone, for example, because of injury or chemotherapy 
    • Secondary testosterone deficiency – low testosterone caused by a problem with another part of the body, such as a problem with the pituitary gland 

    Low testosterone doesn’t always cause symptoms. However, the range of symptoms associated it with it include: 

    • Erectile dysfunction 
    • Hair loss 
    • Loss of sex drive  
    • Fatigue 
    • Low mood 
    • Weight loss or weight gain  

    Obesity is also strongly associated with low testosterone. Losing weight through lifestyle changes, such as eating a healthy diet and regular exercise are recommended if this is the cause of low testosterone. 

    A finger-prick blood test will report on the testosterone levels in your blood and indicate if it’s within the normal range. If your level is abnormal, the next step is establishing the cause.  

    LloydsPharmacy Online Doctor’s healthy lifestyle hub 

    Our lifestyle advice hub is here for you with clear and simple advice on losing weight, stopping smoking, and leading a more balanced lifestyle.  



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