^^^ no such thing as blue veins, blood is red always, it doesn't change colors. it appears blue (more likely maroonish/blue) because of your skin tone and the way light hits it.. giving the appearance of blue.. probably its giving that color off cause of your increased hemaglobins IMO, in fact i would bet my left nut that was the reason. do a blood test and i bet your hemaglobins will be sky high. has to do with oxygen in the blood as well. thats what AAS do, your kidney's are getting strained but will return to normal after cycle. thats why you cycle off to give the good ole kidney's a break. and your blue veins will slowly return to normal hopefully, but keep in mind deca sticks around a long time in the body so make sure you give yourself extra time off in between cycles