A groundbreaking long-term study has turned conventional wisdom on its head, revealing that modest rises in blood sugar—not age or testosterone—are a primary driver of sexual decline in men. Presented at ENDO 2025, the Endocrine Society’s annual meeting, these findings highlight that even non-diabetic glucose levels can slow sperm, impair erections, and reduce libido, with important implications for men’s health across Thailand and the world (SciTechDaily).
For years, discussions about aging men’s declining sexual and reproductive health have focused on hormone levels and the inevitable march of time. But this newly published research, led by a respected German endocrinologist, argues that subtle metabolic changes—particularly slight increases in blood sugar—play a more pivotal role than previously recognized. “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,” said a University Hospital in Muenster professor involved in the study. This suggests that lifestyle management and blood sugar monitoring may hold the key to preserving sexual health as men age.
The study, officially known as FAME 2.0, followed a cohort of initially 200 healthy men, aged 18 to 85, from 2014 to 2020. None had a history of diabetes, heart disease, or cancer at the outset. Over the years, the remaining 117 participants underwent comprehensive evaluations of semen quality, hormone levels, erectile function, body mass index (BMI), and the blood marker HbA1c—a key indicator of average blood sugar over several months. The results were clear: while most hormone and semen parameters stayed within normal limits, men with even slightly elevated blood sugar below the diabetic threshold (less than 6.5% HbA1c) experienced noticeable declines in sperm motility and erectile function. Intriguingly, testosterone levels did not appear to affect erectile performance directly, though they continued to be associated with self-assessed libido.
This shift in perspective is vital for Thai men, where lifestyle-related metabolic issues—such as prediabetes and rising obesity rates—are increasingly common. According to national statistics, Thailand faces a significant and growing burden of metabolic diseases. The National Health Examination Survey (2019) reported that over 10% of Thai adults have diabetes, but a much larger portion live with undiagnosed prediabetes or high-normal blood sugar, conditions that may quietly undermine sexual and reproductive health (Thai Ministry of Public Health). Notably, these blood sugar elevations frequently result from changes in diet and inactivity—a pattern observed in both urban Bangkok and in rapidly developing provincial cities.
In the context of Thai culture, where issues related to masculinity and sexual performance are often discussed with discretion if not outright secrecy, the new research offers an opportunity for conversation and early intervention. Traditional beliefs frequently attribute sexual changes to natural aging or “waning virility,” sometimes spurring reliance on herbal remedies or supplements. However, as this latest research illustrates, modifiable lifestyle factors might be far more powerful than previously believed, potentially reducing dependence on costly or unproven “miracle cures.” Local men’s clinics and Thai urologists have expressed increasing concern about the influence of “sweet” diets and sedentary lifestyles on younger men’s health, paralleling global findings (Bangkok Post Health Desk).
Expert opinions echoed throughout the ENDO 2025 meeting and other medical literature reinforce the message of optimism and responsibility. The German study lead noted, “We now know that it’s in our power to retain sexual and reproductive well-being in men, even as they age.” Medical professionals around the world, including those at leading Thai hospitals, emphasize early detection of metabolic risks and routine blood sugar monitoring as cost-effective public health measures. One endocrinologist at a top Bangkok hospital explained in a recent interview, “Prevention, including dietary counseling and encouragement of regular physical activity, should begin early—well before men experience obvious symptoms.”
Historical and social context is critical for understanding why these findings matter now. Over the past two decades, Thailand has undergone rapid urbanization, with corresponding shifts in dietary habits—for example, the increasing consumption of processed, sugary beverages and fast foods. While rice and traditional Thai dishes remain staples, Western-style snacks and sugary drinks are now ubiquitous, especially in cities. The average daily sugar intake in Thailand is above the World Health Organization’s recommended levels, and sugary beverages are a leading source (WHO: Thailand Sugar Consumption). Public health campaigns warning of diabetes and obesity have made progress, but younger men may not realize that the same dietary patterns could directly impact their sexual vitality even before classic metabolic disease sets in.
Looking ahead, the FAME 2.0 findings could spur a new era in men’s health awareness—not just in Germany, but across Asia and particularly in Thailand, where rising prosperity is coupled with increased risks for metabolic syndrome. Medical experts suggest routine screening for early blood sugar elevations in men presenting with sexual health concerns, even if they are not yet diabetic by official thresholds. In practice, this could mean regular monitoring of HbA1c, lifestyle counseling focusing on reduced sugar intake, and routine physical activity. There is also growing interest among Thai health researchers in adopting similar longitudinal studies locally to further explore cultural, dietary, and genetic contributions to metabolic risk.
In summary, the shift from aging and testosterone to blood sugar management as a key factor in men’s sexual health is a call to action for Thai readers and the broader community. Men should not wait for overt symptoms or the onset of diabetes before taking their health seriously. Simple steps—such as moderating sugar consumption, engaging in regular exercise, and getting routine check-ups—can go a long way toward maintaining reproductive and sexual vitality throughout life. For families and health professionals, fostering open dialogues and combating stigma around men’s health may help dispel old taboos and encourage proactive care.
In the Thai context, where male roles, family expectations, and health-seeking behaviors often intersect with cultural traditions, these new findings offer hope. They also suggest the value of collective action in schools, workplaces, and communities to promote healthier, less sugar-centric lifestyles. In the words of Thailand’s leading endocrinologists, “A small change in daily habits can mean a big difference in long-term well-being—for men and those who care about them.”
For more information on sugar management, sexual health, and local health resources, consult the Thai Ministry of Public Health, leading hospitals, and public education materials on diabetes and metabolic syndrome.