Stretch marks: why they form and how they are treated

Published: 29 July 2026 · Medically reviewed by: Op. Dr. Murat Alpay

What causes stretch marks (striae), the difference between the early red stage and the later white stage, and the treatments used to improve their appearance.

Stretch marks are among the most common concerns raised after childbirth. Known medically as striae distensae, they are marks that sit lower than the surrounding skin (atrophic), formed when collagen and elastin fibres in the deeper layers are damaged by the skin being stretched mechanically.

What causes them

• Pregnancy. They usually appear after about the 24th week, as abdominal tension increases and hormones change, particularly on the abdomen and breasts.
• Rapid weight gain and loss. The body expanding and contracting over a short period creates mechanical stress in the skin.
• Hormonal and genetic factors. A genetic predisposition, hormonal change during puberty, or an endocrine disorder such as Cushing's syndrome can all trigger them.
• Medication. Long-term steroid medicines, taken by mouth or applied to the skin, thin the skin and can lead to stretch marks.

The two stages

When they first form, stretch marks are usually red, pink or purplish — striae rubra. At this early stage there is increased blood vessel activity. Over time they fade to a pearly white, wrinkled and slightly depressed scar-like appearance — striae alba. Treatment at the early, reddish stage generally responds more readily.

How they are treated

The aim of treatment is to stimulate new collagen and elastin production in the damaged area so that the skin repairs itself. The methods most often used are:

• Fractional radiofrequency microneedling. Radiofrequency energy delivered beneath the skin through micro-needles triggers collagen production. It is effective in reducing the size of stretch marks caused by pregnancy or weight change and in improving the quality of the skin.
• Microneedling. Micro-channels are opened in the surface of the skin, engaging the body's natural wound-healing mechanism. It stimulates collagen synthesis without thinning or peeling the skin.
• PRP (platelet-rich plasma). Repair cells — growth factors — obtained from the person's own blood are delivered to the affected area. In treating stretch marks it is frequently used alongside the other methods to support renewal of the skin.
• Fractional laser and chemical peels. Alongside superficial peels such as glycolic acid and TCA, fractional lasers create microscopic zones of damage that support remodelling of the connective tissue.

The right method and session plan for you are determined by examination.