Erectile Dysfunction Blood Test Kit

Testosterone is the primary male sex hormone, produced mainly by the testes under control of the pituitary gland. It's essential for sexual desire (libido), erectile function, sperm production, muscle mass, bone density, red blood cell production, mood, and energy levels. Testosterone levels naturally decline with age—approximately 1-2% per year after age 30—but some men develop clinically low testosterone (hypogonadism) that causes symptoms. Low testosterone is a common and treatable cause of erectile dysfunction, affecting an estimated 40% of men over 45 to some degree. Symptoms include reduced libido, difficulty achieving or maintaining erections, fatigue, reduced muscle mass, increased body fat, low mood, and poor concentration. However, ED can occur with normal testosterone levels (when vascular or neurological factors are the cause), and some men with low testosterone maintain erectile function. Testosterone should be measured in the morning (6-10am) when levels peak. If low, repeat testing and further investigation are needed before treatment. Results outside the normal range may need a follow-up with your GP.

Prolactin is a hormone produced by the pituitary gland that's primarily known for stimulating milk production in women. In men, prolactin is normally present at low levels and plays a role in reproductive function. However, elevated prolactin (hyperprolactinaemia) in men suppresses the production of GnRH (gonadotropin-releasing hormone), which in turn reduces testosterone production and causes erectile dysfunction, reduced libido, and potentially infertility. Causes of elevated prolactin include pituitary tumours (prolactinomas—usually benign), certain medications (particularly antipsychotics, some antidepressants, and anti-nausea drugs), hypothyroidism, kidney disease, and stress. Even mildly elevated prolactin can contribute to sexual dysfunction. Prolactin levels are affected by recent sleep, stress, nipple stimulation, and sexual activity, so the test should be taken at least one hour after waking, in a non-stressed state, and without recent sexual activity or nipple stimulation. Results outside the normal range may need a follow-up with your GP.

TSH is produced by the pituitary gland to regulate the thyroid gland, which controls metabolism and affects virtually every organ system including sexual function. TSH works as part of a feedback loop—when thyroid hormone levels are low, TSH rises to stimulate the thyroid; when thyroid levels are high, TSH falls. TSH is the most sensitive initial marker of thyroid dysfunction. Both hypothyroidism (underactive thyroid, indicated by high TSH) and hyperthyroidism (overactive thyroid, indicated by low TSH) can cause erectile dysfunction and reduced libido. Hypothyroidism is more common and causes fatigue, weight gain, depression, and reduced sexual interest. Studies suggest that 60-80% of men with hypothyroidism experience some degree of sexual dysfunction. Hyperthyroidism can cause premature ejaculation and, less commonly, ED. Thyroid dysfunction also affects testosterone metabolism and SHBG (sex hormone-binding globulin) levels, further impacting sexual function. Thyroid disorders are readily treatable, and sexual function typically improves with treatment. Results outside the normal range may need a follow-up with your GP.

Total cholesterol measures all cholesterol in your blood. While cholesterol is essential for hormone production (including testosterone), cell membranes, and vitamin D synthesis, elevated levels damage blood vessels over time through atherosclerosis. Erectile dysfunction is fundamentally a vascular condition—achieving and maintaining an erection requires healthy blood flow to the penis. The same arterial disease that causes heart attacks and strokes also impairs erectile function, often years before cardiovascular symptoms appear. In fact, ED is considered an early warning sign of cardiovascular disease. Results outside the normal range may need a follow-up with your GP.

LDL (low-density lipoprotein) cholesterol is often called 'bad cholesterol' because elevated levels drive atherosclerosis—the build-up of fatty plaques in artery walls. LDL particles deposit cholesterol in the arterial lining, triggering inflammation and plaque formation that narrows and stiffens arteries. The penile arteries are smaller than coronary arteries, so they're often affected earlier by the same disease process. Reducing LDL through lifestyle changes and/or medication can improve both cardiovascular health and erectile function. Results outside the normal range may need a follow-up with your GP.

Non-HDL cholesterol is calculated by subtracting protective HDL from total cholesterol, representing all potentially harmful cholesterol particles—LDL plus VLDL and other atherogenic fractions. Many experts consider non-HDL a superior cardiovascular risk marker compared to LDL alone because it captures the full atherogenic burden. Elevated non-HDL cholesterol indicates increased risk of vascular erectile dysfunction. The target is below 4.0 mmol/L, with lower targets for those at higher cardiovascular risk. Results outside the normal range may need a follow-up with your GP.

HDL (high-density lipoprotein) cholesterol is called 'good cholesterol' because it performs reverse cholesterol transport—collecting excess cholesterol from tissues and artery walls and returning it to the liver for disposal. Higher HDL levels are protective against cardiovascular disease and support healthy blood flow, including to the penis. Levels above 1.0 mmol/L are desirable. Regular aerobic exercise and maintaining a healthy weight are effective ways to raise HDL. Smoking significantly lowers HDL and impairs erectile function through multiple mechanisms. Results outside the normal range may need a follow-up with your GP.

The cholesterol: HDL ratio indicates what proportion of your total cholesterol is protective HDL versus potentially harmful LDL and other fractions. A lower ratio indicates a more favourable lipid profile and reduced cardiovascular risk. The ratio is used in cardiovascular risk assessment tools to calculate your overall risk of heart attack or stroke. An ideal ratio is below 4; a ratio above 6 indicates significantly increased cardiovascular risk. Lower ratios support better vascular health and erectile function. Results outside the normal range may need a follow-up with your GP.

Triglycerides are fats that circulate in your blood, providing energy to cells. Elevated triglycerides are associated with cardiovascular disease and are often part of metabolic syndrome—a cluster of conditions including abdominal obesity, high blood pressure, elevated blood sugar, and abnormal cholesterol that significantly increases the risk of both heart disease and erectile dysfunction. High triglycerides often reflect excess calorie intake, high sugar/refined carbohydrate consumption, alcohol, or poorly controlled diabetes. The target is below 1.7 mmol/L. Results outside the normal range may need a follow-up with your GP.

HbA1c measures your average blood glucose control over the past 2-3 months by detecting how much glucose has attached to haemoglobin in your red blood cells. It's the gold standard test for screening for and monitoring diabetes. Diabetes is one of the most significant risk factors for erectile dysfunction—studies suggest that 35-75% of men with diabetes experience ED, often at a younger age than men without diabetes. High blood sugar damages blood vessels (causing atherosclerosis) and nerves (diabetic neuropathy), both of which impair erectile function. The blood vessels supplying the penis are particularly vulnerable. Additionally, diabetes is associated with lower testosterone levels and increased inflammation. Identifying prediabetes (HbA1c 42-47 mmol/mol) gives an opportunity to intervene before full diabetes develops. Normal is below 42 mmol/mol; diabetes is diagnosed at 48 mmol/mol or above. Results outside the normal range may need a follow-up with your GP.