Blood Sugar, Not Just Age, Linked to Male Sexual Decline
Summary: A new study refutes the popular assumption that low testosterone or ageing itself is responsible for deteriorating men’s sexual health. Rather, moderate increases in blood sugar, far below diabetic levels, can reduce sperm motility, reduce erections, and impact libido. Blood glucose regulation, researchers argue, may help preserve men’s sexual and reproductive health during ageing.
Blood Sugar and Sex Health: A Game-Changer
New research presented at ENDO 2025, the Endocrine Society’s annual meeting, suggests that minor increases in blood sugar, even in non-diabetic men, could have a greater impact on male sexual function than age or testosterone levels alone.
“These changes more closely correlate with modest increases in blood sugar and other metabolic changes,” said lead researcher Dr. Michael Zitzmann, professor at University Hospital in Muenster, Germany
Findings of the Study
The results rely on the FAME 2.0 study, a decade-long study conducted from 2014 to 2020. The original 200 healthy men aged 18 to 85, all of whom were free of diabetes, cancer, and heart disease, were recruited. A total of 117 remained by the final count.
Researchers monitored the following long-term:
- Semen quality
- Hormone levels
- Erectile function
- Metabolic markers, including BMI and HbA1c (a prominent blood sugar indicator)
Even when overall hormone concentrations and semen volume remained in the normal range, sperm motility and erectile function were impaired in individuals with only an elevated blood glucose (although not in diabetic range of HbA1c 6.5% or more).
Interestingly, testosterone levels had little effect on erections, although they were correlated with libido.
Why It Matters: Glucose Over Hormones?
This flips on its head a large narrative around men’s health. Testosterone and ageing are usually blamed for sexual decline, but this study shows that glucose metabolism plays a greater role than was appreciated.
That’s good news, because while age cannot be avoided, blood sugar can be controlled with:
- Eating a balanced diet (low-refined-carb)
- Exercise regularly
- Weight maintenance
- Following up with your doctor on HbA1c levels
Takeaway: Sex Health in Your Hands
Dr. Zitzmann emphasises hope and empowerment:
“We now know it’s in our power to retain sexual and reproductive wellbeing in men, even as they age.”
That is, dietary modifications that regulate blood sugar can enhance your sex life better than testosterone supplements or anti-ageing interventions.
Dane
I am an MBBS graduate and a dedicated medical writer with a strong passion for deep research and psychology. I enjoy breaking down complex medical topics into engaging, easy-to-understand content, aiming to educate and inspire readers by exploring the fascinating connection between health, science, and the human mind.
