The basic reason why skin develops stretch marks is that it has lost some of its collagen and elastin, which are sub-dermal skin- supporting fibers. The loss of these fibers occurs naturally during the aging process, but there are other factors which can cause stretch marks as well.

Any time your skin is excessively stretched for an extended period, its elastin and collagen fibers will break down, and a stretch mark will appear. Stretch marks are actually form of scars, which result when collagen production is halted.

Like scars from wounds, stretch marks will first appear as reddish or purplish lines, but with time will get much lighter so that they are nearly the same shade as the healthy skin surrounding them. It is their different texture and somewhat shiny appearance that makes even faded stretch marks visible.

Stretch marks will also be one unwanted consequence of long-term steroid use, and can affect people who are required to take steroids for medical conditions as well as those who use them to enhance athletic performance.

Pregnancy and weight gain, of course, are associated with the development of stretch marks. Both conditions may force the skin to stretch more than normal, but some women who don't gain enough pregnancy weight to cause stretch marks can end up with them anyway because of the hormonal changes which they are experiencing. Unfortunately, the stretch marks which come from pregnancy and weigh gain will not vanish when the extra weight is lost or the baby has been delivered. While they may shrink somewhat, stretch marks never completely disappear.

You can expect stretch marks to appear, if they are going to, on the areas of your body where you have the most fat cells. The thighs, breasts, buttocks, and abdomen are the classic problem areas when it comes to stretch marks, but some people also develop them on their hips and upper arms.

Understanding why you may get stretch marks is the first step to learning how to minimize them. We'll look at ways to remove stretch marks in future articles!