The jelq combines elements of mechanical force and hormonal influence to stimulate growth. The physical act of jelq stimulates the release of vascular relaxing factors and prostaglandins, especially PGE-1 which promotes relaxation of the vessels and tissues. If you notice, sometimes you have a great jelq session where your penis expands and swells with every stroke and another time the session just does'nt seem to be as good. This has alot to do with PGE-1. Excessive and hard jelqing can also produce inflammatory prostaglandins, not good. Result being inflammatory swelling and soreness, not to be confused with hypertrophy of the penis (growth).
PGE-1 is necessary for erection to occur. When the tissues of the penis have sufficient PGE-1 levels, the mechanical forces of jelqing allow the tissues to stretch to their maximum. This enables maximum engorgement of the tissues with nutrient and hormone rich blood. The body responds to these physical stresses by increasing cellular division to accomodate the pressure of the forced blood squeezed in by jelqing.
When the neuroendocrine system becomes sexually aroused, a cascade of hormonal changes occur. Testosterone levels increase and the conversion of testosterone via 5-alpha reductase to the more androgenic metabolite, dihydrotestosterone (DHT) increases in the tissues of the penis and accessory organs of the genitals (seminal vesicals, prostate, cowpers glands, testicles, ect). In responce to the increase androgen production, androgen receptors which are abundant in the genitals will increase in quantity and sensitivity to circulating androgens. Testosterone and especially dihydrotestosterone are essential for the function, maintainance and development of the genitals.
These are medically proven facts. Penis enlargement works and there should be no doubting this reality. It is time tested. Men have been enlarging there penis's since we figured out that it feels good to touch it.
Doubt exists because of misapplied technique, resulting in failure.