Stretch marks are called stria atrophicae in the field of dermatology. They are often characterized as scarring on the skin due to weight gain. They appear on body parts where higher amounts of fats are accumulated. Such body parts are the thighs, hips, buttocks, and the abdomen.

Stretch marks are produced from the over-stretching of the middle layer of the skin namely, the dermis. This layer stretches to its maximum capability to be able to fit a larger body. This would result to microscopic bleeding and tissue inflammation and would manifest as reddish-purple lines on the skin. Also, this would cause the outer layer of the skin to expand making the lines visible enough. The stretch marks would appear once these lines heal and would have a shade lighter than the natural skin tone.

Some studies suggest that glucocorticoids, a group of steroids, are associated with stretch marks. Cortisol is the most common example of a glucocorticoid. Research showed that when the body is at stress, it releases cortisol at a level above its normal amount. This could halt fibrolasts from forming elastin fibers and collagen, which are essential for keeping a new skin firm. This would ultimately lead to the tearing of the epidermal and dermal layer due to lack of these supporting materials.

Excess amounts of cortisol could inhibit the formation of elastin fibers and collagen from fibrolasts, which are both needed to keep new skin firm. As a consequence, the dermal and epidermal layer of the skin could tear easily due to the absence of these supportive substances.

On the other hand, retinoids and alpha-hydroxy acids negate the bad effects caused by steroids. And this combination reduces the formation of stretch marks.

There are other methods available to help remove and prevent stretch marks. Such methods are laser treatments, use of prescription retinoids, and dermabrasion. Dermabrasion uses pulses of light to remove the outer most surface of the epidermis. This is done to remove not only stretch marks, but also dark and sun-damaged skin.

Another method uses a surgical procedure, the tummy tuck. In here, the part of skin below the navel is being removed because this is where stretch marks oftenly form.