Hello Doctor, Good Day !!! My age is 25 years,Height 6 foot & weight 68 kgs ( as of now previously weight was very low ) smoking 2-3 cigerates a day & drinking whishkey on weekends is in habit ( drinking wine now a days).My problem is ED. I would like to decribe my past life which will healp to understand problem easily. I started masturbation when i was in age of 18.My penis rock hard during masturbation.during that time I came in contact of a person who requested for anal sex with him I made anal sex relation many time during that time with him.A idea to do sex with him was enough for my penis erection rock hard when i move from my room towards him (his room was on walking distance) .during the year 2009 I went out for the higher study & not found the chance for sexual relation but contineued the masturbation once within 3 days. my body weight was very low comparatively one of my close friend suggested me to take Dexona-Practine ( cyproheptadiene with decadan) which increases my hunger thus my body weight increased on satisfactory level .I used above medicine from june 2012 to till date intermediately ( taken dose till 3 month then stoped again felt losing weight so again started). from last one year I am abroad during previous month I found the first chance of natural sex with a beautifull chinese girl,I was very surprise My penis not erected she tried a lot by oral stimulation but it erects and within few minuts when I penetrated goes down.I was in fully relaxed mood.surprising thing is that before 7 year my penis was rock hard now it is in such condition as I can not penetrate. Latter on I tried a lot with other girls also the same things happens penis not erected sometime, it erected by trying stimulation but again been loose.When I masturbate it hard not much but I feel that I can penetrate with it. Please guide me as I could back my sexual power as much as was during 18.