From MEN’S HEALTH:
Researchers found that guys over the age of 20 who consumed the caffeine equivalent of 2 to 3 cups of coffee a day were less likely to report ED issues than men who steered clear of the stimulant. The connection was strongest in overweight guys, says study author David Lopez, Dr.P.H., M.P.H., but he plans to dive further into how the caffeine/ED link can affect different weight groups. Caffeine has properties similar to ED drugs like Viagra, says study coauthor Run Wang, M.D. The stimulant triggers a series of effects that cause the arteries in your penis to relax and your blood flow to increase—both keys to a strong erection.
Thanks for your vigorous efforts, Dr. Wang! – Mike