The only evidence as regards pumping is strictly anecdotal. No medical studies have ever been done on pumping. Doctors claim the gains are temporary, people who pump claim they are not.
According to long-term pumpers, gains are initially temporary but eventually become permanent. With nearly every method of enlargement, ceasing all activity results in loss of some but not all gains. It is recommended that anyone involved in PE overshoot their goal size by 1/4"-1/2" to account for the shrinkage which may occur. It's rather like buying clothing one size too large if it is made of fabrics which shrink when washing. Some pumpers, and other PE practitioners simply do maintenance routines once a week or so to keep gains. After a while, those gains will become permanent.
As I have stated before, only one published medical study has ever been done on this and that study was done in the 1970s. The study showed that a statistically significant sample of jelq practitioners did gain measurably (about an inch), after a three month period.
No follow-up study has ever been done.
Anything else said about PE, whether by guys doing it OR those in the medical community who criticize it, is strictly anecdotal.
Im inclined to agree with you Jason regarding the evidence surrounding any form of penis enlargement, whether it be pumps, extenders, or manual stretching. Its purely anecdotal from those claming personal success and its baseless from those claiming it doesnt work.
Not that I didnt believe your claim that a medical study was done in the 1970s but out of interest I wanted to read it for myself to see how it was conducted etc. Consequently, I searched on the Internet and came up with absolutely silch! What I did find though were claims from many companies producing aids for penis enlargement that endorsed their own product over any other. Claims like, Doctors found that unlike penis pumps, that only produce temporary gains, our product produced permanent gains of up to 12 in 3 months! Or Our tests were carried out world wide on over a 100 men! (as many as that? Wow!) That sort of thing. I also came across an article on Wikipedia, though knowing some of it to be inaccurate has now caused me to doubt the validity of the site as a whole? And although I found several instances where studies were referred to, I couldnt actually find the studies themselves. All in all, it appears theres a lot of crap out there and little else. Interestingly, there appears no scientific evidence against penis enlargement, any doubt, by and large, comes from the medical sector and is invariably the quote of a doctors opinion. There is never any evidence from clinical trials, or claims by the doctors that they personally have tested whatever aspect they criticise, themselves. What we do have however, albeit anecdotal, is the testimonies of a significant number of guys, like me, without a vested interest in products, like those who jelq, stretch, or make their own equipment, who claim penis enlargement does work and on that I rest my case. BTW, if you can point me in the direction of said article, Id still be interested in seeing what it says and would be very grateful.
Sea