There is no such thing as penile exhasution. If you do not have a medical condition, then there is one answer for a decline in penile erection health for your age group. That is over use of porn.
Not masturbation, but Internet porn. It desensitizes the brain over time. We see men your age all the time with porn-induced ED. Experts and doctors no nothing about it becuase they think masturbation cannot cause ED (they are right), and therefore Internet porn cannot caused ED (they are wrong).
It's happening in your brain not your penis. Follow this link to another long thread. Read the many posts.
Find my first few posts on this thread as they have links to video presentations and articles that explain it all.
http://www.medhelp.org/posts/Mens-Health/22-with-porn-induced-erectile dysfunction/show/469209?page=1
Here's one research study-
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SCIENTISTS: TOO MUCH INTERNET PORN MAY CAUSE IMPOTENCE (2011)
It may not make you go blind, but Italian scientists have identified a worrying side-effect of watching too much pornography.
Researchers said Thursday that young men who indulge in "excessive consumption" of Internet porn gradually become immune to explicit images, the ANSA news agency reported.
Over time, this can lead to a loss of libido, impotence and a notion of sex that is totally divorced from real-life relations.
"It starts with lower reactions to porn sites, then there is a general drop in libido and in the end it becomes impossible to get an erection," said Carlo Foresta, head of the Italian Society of Andrology and Sexual Medicine (SIAM).
His team drew their conclusions from a survey of 28,000 Italian men which revealed that many became hooked on porn as early as 14, exhibiting symptoms of so-called "sexual anorexia" by the time they reached their mid-twenties.
There was some good news, however, as the condition was not necessarily permanent. "With proper assistance recovery is possible within a few months," Foresta said.