For years, declining testosterone levels have been blamed for reduced sexual performance in aging men. However, new research reveals that mild metabolic changes—particularly slight increases in blood sugar—are the primary cause of erectile dysfunction, not low testosterone.
Dr. Michael Zitzmann, a professor and sexologist at University Hospital in Munich, Germany, led the study which challenges long-held beliefs. “Our findings show that sexual health decline in men is more closely linked to rising blood sugar levels and subtle metabolic shifts rather than testosterone levels,” Dr. Zitzmann explained.
The study tracked 200 healthy men aged 18 to 85 from 2014 to 2020, focusing on those free of diabetes, heart disease, or cancer to isolate metabolic effects. Despite normal hormone levels and sperm quality, erectile function significantly declined in men with slightly elevated blood sugar—levels still below diabetic thresholds.
“We observed a clear drop in erectile function as blood sugar increased, even mildly. Testosterone did not correlate with erectile ability, though it did relate to sexual arousal,” Dr. Zitzmann added.
Presented at the 2025 ENDO annual meeting in San Francisco, these findings suggest erectile dysfunction is not inevitable with age. Lifestyle improvements and targeted medical care can help men preserve sexual health well into later years.
With testosterone replacement therapy gaining popularity despite potential risks, this research offers alternative approaches emphasizing metabolic health. Nutrition and habits also matter; a separate study notes that certain drinks like wine juice may boost libido.
Experts recommend these practical steps to maintain sexual and overall health: avoid excessive sugar intake, maintain a healthy weight, quit smoking, limit alcohol, exercise regularly, and monitor blood sugar levels.
Adopting these habits not only supports sexual function but also reduces risks for serious metabolic diseases such as diabetes and cardiovascular conditions.
