One of the primary causes of ED is usually a buildup of the phosphodiesterase sort 5 (PDE5) enzyme that restricts blood move in your penis and stops or lessens the firmness of an erection.?Oiai ?o ka ho?owalewale o ka loa?a ?ana i ka hi?ohi?ona p? o Montreal he mea ho?owalewale, ?o ka ho?ohana ?ana i kahi ID ho?opunipuni e hele mai me n? pilikia nu