Researchers from the University of Gothenburg have reported that tadalafil, a medication commonly used for erectile dysfunction, may help reduce long-term blood sugar levels in people with type 2 diabetes. The findings appear in the journal eClinical Medicine, signaling a potential new avenue for managing glucose control in this population.
In the study, eighteen participants were enrolled, consisting of twelve men and six postmenopausal women. The trial design involved two six-week treatment periods with a crossover structure. During the first phase, half of the participants received high daily doses of tadalafil while the other half received a placebo. After an eight-week washout interval, the groups swapped treatments for a second six-week period. This approach allowed researchers to compare the effects of tadalafil against placebo within the same individuals, helping to account for personal variability in response.
Analysis showed that tadalafil did not alter insulin sensitivity in the participants. Yet a notable finding emerged in the marker HbA1c, a long-term indicator of average blood glucose levels over several weeks to months. On average, HbA1c declined by 2.50 mmol/mol among those who took tadalafil compared with placebo. A reduction in HbA1c is meaningful because it reflects sustained improvement in glucose control rather than short-term fluctuations.
Experts emphasize that a lower HbA1c level is associated with a reduced risk of diabetes-related complications. These complications can involve the small vessels in critical organs, including the eyes, kidneys, and nerves. While the results are encouraging, the researchers caution that the study was small and short in duration. They stress the need for larger trials conducted over longer periods to confirm the effects and determine the most effective dosing strategies for diverse patient groups.
Given the wide range of tadalafil’s known side effects, careful medical supervision is essential. Reported adverse effects in clinical use commonly include headaches, stomach upset, muscle or back discomfort, lightheadedness from low blood pressure, nasal congestion, ringing in the ears, and blurred vision. Because tadalafil influences vascular tone and systemic blood flow, improper use or self-medication with tadalafil or similar drugs can pose serious health risks. Medical professionals generally advise against self-prescribing these medications outside of approved indications and supervised treatment plans.
The potential discovery of a glucose-lowering effect for tadalafil invites a broader discussion about repurposing existing drugs to support diabetes management. If future studies corroborate these initial observations, tadalafil could become part of a broader toolkit for improving long-term glycemic control in type 2 diabetes. Until then, standard therapies, lifestyle changes, and ongoing clinical guidance remain the cornerstone of diabetes care. This line of research underscores the importance of rigorous testing and patient safety while opening a conversation about how approved medications might be leveraged to benefit metabolic health in a controlled, evidence-based manner.