What can a blood test tell you about your erections?

Most men don’t think about getting a blood test when things aren’t working in the bedroom. But the truth is, a simple blood test can reveal a lot about male sexual function. From low testosterone levels to underlying conditions like diabetes and high cholesterol, blood tests offer deeper insights into what’s really going on beneath the surface.

Erectile dysfunction (ED) and reduced sex drive aren’t just about age or stress. In many cases, there’s a medical reason behind them—one that can be identified and managed with simple blood tests.

What can blood tests tell you about sexual function?

Blood tests for male sexual function fall into two broad categories: 

• Hormone blood tests: These tests identify specific conditions that can be directly treated, leading to noticeable improvements in erectile function.¹ 

• Cholesterol and glucose tests: These types of tests reveal underlying health issues that may not cause immediate sexual problems but can lead to serious complications down the line if left unaddressed.¹

A study of 1,455 men with ED found that 28% had an underlying biochemical abnormality. In a smaller subset who were tested for cholesterol, that figure jumped to 42%.¹

Here’s what blood tests can detect:¹

• Low testosterone: Testosterone plays a major role in libido, erectile function, and overall sexual performance. When levels drop below the normal range (11–37 nmol/L), it can result in reduced sex drive, weaker erections, and lower energy levels.

• High cholesterol: Elevated cholesterol can lead to restricted blood flow, making it harder to achieve and maintain an erection.

• High blood sugar: Undiagnosed diabetes or insulin resistance can damage nerves and blood vessels, leading to persistent ED.

• Liver function issues: Liver disease, often linked to excessive alcohol intake, can interfere with hormone production and circulation, affecting sexual performance.

Why testosterone matters for sexual performance

Testosterone is the primary male sex hormone, responsible for everything from muscle mass to mood regulation. But its most well-known role is in sexual function. When testosterone levels fall too low, men can experience a range of symptoms, including fatigue, reduced libido, weaker erections, and difficulty maintaining arousal.

The treatment for low testosterone is often testosterone replacement therapy, depending on your levels and meeting the criteria. That being said, testosterone replacement therapy isn’t a magic fix for everyone. For instance, in the study above which looked at abnormalities in blood markers in men with ED, showed that men whose testosterone levels were slightly below normal don’t always experience improvements in their ED, suggesting that other factors like overall vascular health also play a key role.¹

The overlooked role of blood sugar and cholesterol

Many men assume that ED is purely a hormonal issue, but cardiovascular and metabolic health are just as important. High cholesterol and blood sugar levels can cause long-term damage to blood vessels, restricting blood flow to the penis and making erections weaker or harder to maintain.²

In one study, 15% of men had high cholesterol, and 9.3% had elevated glucose levels. Notably, 30% of men with high cholesterol also had high blood sugar, indicating a strong link between metabolic health and erectile function.¹

Diabetes is one of the leading causes of ED, and in many cases, men discover they have diabetes only after seeking treatment for sexual health concerns.² Uncontrolled blood sugar levels can damage nerves and blood vessels, leading to a condition known as diabetic neuropathy, which directly affects erectile function.²

Could liver function be affecting your performance?

Liver function might not be the first thing that comes to mind when thinking about sexual function, but the liver plays a key role in hormone regulation and detoxification.³ If it’s not working properly, testosterone metabolism can be disrupted, leading to imbalances that affect libido and performance.³

In the first study looking at blood marker abnormalities in men with ED, 12.8% of men had abnormal liver function tests, and in most cases, this was linked to excessive alcohol intake.¹ Heavy drinking not only affects testosterone production but also contributes to nerve damage and poor circulation, both of which can worsen ED.^1,3

What does the Numan Sexual Performance blood test cover?

If you’re experiencing issues with sexual performance, the Numan Sexual Performance blood test can help pinpoint potential causes. Here are the key markers we can provide insight into:

1. Testosterone levels 

2. Cholesterol

3. Liver function 

The numan take

Erectile dysfunction is often a symptom of a deeper health issue. Whether it’s low testosterone, high cholesterol, or liver function problems, simple blood tests can provide valuable insight into what’s going on with your body. For some men, addressing these imbalances can lead to significant improvements in sexual performance. But even if ED isn’t immediately resolved, identifying and managing these health risks can improve long-term wellbeing, reducing the risk of heart disease and other serious conditions.

References

1. ^{Earle CM, Stuckey BGA. Biochemical screening in the assessment of erectile dysfunction: what tests decide future therapy? Urology [Internet]. 2003;62(4):727–31. Available from: http://dx.doi.org/10.1016/s0090-4295(03)00508-9} 

2. ^{Defeudis G, Mazzilli R, Tenuta M, Rossini G, Zamponi V, Olana S, et al. Erectile dysfunction and diabetes: A melting pot of circumstances and treatments. Diabetes Metab Res Rev [Internet]. 2022;38(2). Available from: http://dx.doi.org/10.1002/dmrr.3494} 

3. ^{Zang G, Sun X, Sun Y, Zhao Y, Dong Y, Pang K, et al. Chronic liver diseases and erectile dysfunction. Front Public Health [Internet]. 2023;10. Available from: http://dx.doi.org/10.3389/fpubh.2022.1092353}