We have three layers of skin: the epidermis (outer layer), the dermis (middle layer), and the subcutaneous stratum (innermost layer). Stretch marks occur in the dermis, the resilient middle layer that helps the skin retain its shape. When the dermis is constantly stretched over time, the skin becomes less elastic and the small connective fibres within it break. The result is what we know as stretch marks.

Laser surgery is currently being developed for the treatment of stretch marks. This treatment doesn't remove stretch marks - it simply makes them fade. The laser responds to dark colours only, so in the early stages when stretch marks are dark red or brown, treatment will be most effective. Faded, flesh-coloured marks probably won't respond well to laser treatment because they are light in colour. A series of treatments might be required for visible results.