A new international study has revealed that even modest increases in blood sugar levels—not just advanced diabetes—can have a significant negative impact on men’s sexual health as they age, shifting the traditional understanding of male reproductive well-being. The latest findings, presented at the Endocrine Society’s ENDO 2025 annual meeting in San Francisco, spotlight metabolic health, especially mild hyperglycemia, as a key driver in changes to sexual functioning among men, offering a new roadmap for prevention and intervention.
For decades, age and testosterone decline have been widely regarded as the main culprits behind deteriorating male sexual health. However, the recent research led by a team from University Hospital in Muenster, Germany, upends this belief. Quoted in the official announcement, the leading professor and physician investigator emphasized, “Although age and testosterone levels have long been considered an impetus for men’s declining sexual health, our research indicates that these changes more closely correlate with modest increases in blood sugar and other metabolic changes. This means that men can take steps to preserve or revive their reproductive health with lifestyle choices and appropriate medical interventions” (newswise.com).
The long-term FAME 2.0 study, which tracked healthy men aged 18 to 85 starting in 2014 and concluding in 2020, is the basis for this paradigm shift in understanding. Throughout the research, 200 participants (117 by the study’s end) were monitored for progressive changes in sperm quality, hormone levels, erectile function, and metabolic health—including blood sugar measured by the HbA1c test. Notably, none of the participants had diabetes, heart disease, or cancer, focusing the findings clearly on otherwise healthy populations.
Researchers discovered that although classic indicators such as total testosterone and overall semen quality tended to remain within normal ranges throughout the years, it was subtle blood sugar elevations—still below the threshold considered diabetic—that heralded declines in sperm motility and erectile performance. Importantly, these blood sugar increases were below the standard HbA1c diagnostic marker of 6.5% for diabetes, highlighting risks that can go unrecognized in typical screenings.
Analysis showed that while testosterone levels continued to play a role in men’s libido, they did not independently predict decline in erectile function. Instead, the pivotal link emerged between blood sugar, metabolic shifts (such as those marked by BMI changes), and physical sexual performance. Researchers hope that “the information gleaned from this study will help doctors and their patients formulate effective male sexual health maintenance plans,” the project’s lead researcher stated, adding, “We now know that it’s in our power to retain sexual and reproductive wellbeing in men, even as they age” (newswise.com).
For men in Thailand and across Asia, these results carry substantial implications. Non-communicable diseases, particularly diabetes and pre-diabetes, are on the rise in Thailand. According to statistics from the Ministry of Public Health and the World Health Organization, Thailand has seen a steady growth in diabetes cases, with prevalence among adults estimated at around 10%, but many more have undiagnosed or “borderline” blood sugar issues (WHO diabetes Thailand). Many adult men remain unaware of how early and moderate sugar elevations, well before “full-blown” diabetes, could silently undermine sexual health and fertility, let alone broader metabolic well-being.
Thais traditionally focus on age, stress, and marital satisfaction as the main drivers of male sexual health. The new evidence, however, draws attention to invisible metabolic factors, underscoring the importance of periodic health screenings—including HbA1c—for men of all ages, regardless of symptoms. Endocrinologists and urologists in Thai hospitals, particularly at leading medical centers such as Siriraj Hospital and Chulalongkorn Hospital, recently have begun advocating for a more holistic, lifestyle-based approach to men’s health. The new research provides further justification for national campaigns and primary care screening for metabolic indicators starting in early adulthood.
The historical context is significant. In Thailand, just as elsewhere in Asia, beliefs about masculine vitality have long centered on hormones, age, herbs, and traditional remedies. Various forms of traditional massage, herbal tonics, and even amulets are promoted for boosting potency, but rarely do such cultural narratives highlight blood sugar or metabolic health as factors. The findings from the German study, therefore, may help initiate a new chapter in public awareness—encouraging proactive steps such as dietary moderation (especially reducing sugar and white rice), regular exercise, and routine metabolic screening as keys to sexual longevity.
The study also highlights a cultural dilemma for Thai men: addressing sexual issues openly remains stigmatized, especially among older generations. The silent impact of “slightly elevated” blood sugar may go untreated for years, contributing not only to sexual dysfunction but to broader health risks such as cardiovascular disease and cognitive decline. Culturally sensitive health education, destigmatizing both sexual and metabolic issues, will be essential for translating the research into real-world benefits.
In terms of future developments, Thailand’s growing burden of lifestyle-related chronic diseases makes it likely that sex health clinics, endocrinology departments, and wellness centers will integrate metabolic screening more systematically into their men’s health checkup packages. The research may drive innovations in patient education, insurance coverage for metabolic testing, and even inspire Thai-specific longitudinal studies to uncover trends unique to local diets and lifestyles.
Looking forward, men in Thailand should consider the following actionable steps:
- Request regular blood sugar and HbA1c tests during annual health checkups, starting as early as their 20s.
- Discuss any changes in sexual health—even mild symptoms—with healthcare providers, knowing that such issues are often linked to modifiable metabolic factors.
- Adopt a lifestyle focused on weight management, balanced nutrition, reduction of refined sugars and carbohydrates, and regular exercise, drawing on both Western and local Thai dietary wisdom.
- Partners and families should support open discussion and destigmatize routine sexual and metabolic health assessments.
Ultimately, this research has empowered men with knowledge: by managing even minor increases in blood sugar and maintaining overall metabolic health, men can preserve not only their sexual and reproductive health but also overall quality of life into old age. As hormone science advances, this insight will be crucial in shaping the next generation of Thai healthcare policy, preventive medicine, and public health communication.
For more on this breakthrough, visit Newswise’s report on high blood sugar and men’s sexual health and the Endocrine Society’s website.