Girls get stretch marks because their skin stretches faster than it can repair itself, most commonly during puberty. About 55% of women report having stretch marks, compared to 25% of men, making this one of the most common skin changes girls experience as they grow. The marks form when the deeper layer of skin tears under tension, and hormonal shifts during adolescence make that tearing more likely.
What Happens Inside the Skin
Your skin has three layers, and stretch marks form in the middle one, called the dermis. This layer contains collagen and elastin fibers that give skin its strength and bounce. When skin stretches too quickly, these fibers rupture. The cells responsible for producing and repairing those fibers (fibroblasts) can’t keep up with the damage, so the skin essentially scars from the inside out.
After the initial tear, the body tries to heal. Immune cells flood the area and break down damaged elastic tissue, then collagen rebuilds along the direction of the stretch. But the repaired tissue doesn’t look or behave like normal skin. The collagen bundles end up thinner, packed flat, and organized in parallel rows rather than the normal basketweave pattern. The result is a visible streak that sits slightly lower than the surrounding skin.
Why Puberty Is the Main Trigger
Stretch marks during puberty happen even in healthy, non-overweight girls. The adolescent growth spurt is enough on its own. Hips widen, breasts develop, and height increases, sometimes within just a few months. That rapid expansion puts enormous mechanical stress on skin that hasn’t had time to adapt.
Hormones compound the problem. During puberty, the body produces higher levels of cortisol, a hormone that directly weakens elastic fibers in the skin. Cortisol also slows fibroblast activity, meaning the cells that should be building new collagen and elastin are working at reduced capacity right when the skin needs them most. It’s a double hit: the skin is stretching faster while its repair system is suppressed.
Where They Typically Appear
In girls, stretch marks tend to show up in the areas experiencing the most growth. The most common locations are the buttocks, thighs, breasts, lower abdomen, hips, and calves. These are all areas where tissue expands significantly during puberty. The pattern differs somewhat from boys, who more often develop marks on the lower back and upper arms. The distribution closely tracks where fat and muscle are being deposited under hormonal influence.
Genetics Play a Real Role
If your mother has stretch marks, you’re more likely to get them too. A large genome-wide study of nearly 34,000 people identified genetic variants near the elastin gene that significantly influence whether someone develops stretch marks. People with certain versions of this gene produce skin with less resilient elastic fibers, making it more vulnerable to tearing under stress.
This genetic connection makes sense given what we know about rare connective tissue conditions. Disorders caused by mutations in the genes for fibrillin (a protein that forms the scaffolding for elastic fibers) are strongly associated with stretch marks. In the general population, the effect is subtler, but the same biological pathway is involved. Some people simply inherit skin that has less built-in stretch tolerance.
How Stretch Marks Change Over Time
Fresh stretch marks look noticeably different from older ones, and understanding the two stages can help you know what to expect. New marks, sometimes called striae rubrae, appear red or purple, slightly raised, and sometimes even a little swollen. This is the inflammatory phase, when the dermis is actively damaged and blood vessels in the area are dilated.
Over months to years, the color fades. Mature marks, called striae albae, turn white or silvery and develop a slightly wrinkled, depressed texture. At this point the skin in the affected area has thinned, lost its normal ridged surface pattern, and has reduced blood supply. The marks become permanent scars, though they typically become much less noticeable over time. This progression from red to white is the same regardless of what caused the marks.
Do Creams and Oils Actually Work?
Despite what product labels claim, no topical cream, oil, or butter has been proven to prevent stretch marks. A Cochrane review, the gold standard for evaluating medical evidence, examined multiple clinical trials of products containing ingredients like cocoa butter, olive oil, vitamin E, and hyaluronic acid. There was no statistically significant difference in stretch mark development between women who used these products and women who used a placebo or nothing at all.
For marks that have already formed, timing matters more than most people realize. Prescription retinoid creams have shown some effectiveness on newer, red-stage marks, reducing their length and width over several months of daily use. But once marks have matured to the white, scarred stage, topical treatments offer very limited improvement. Even in the studies that showed benefit, about half of participants experienced skin irritation like redness and peeling in the first month or two of treatment.
Why Being Female Increases Risk
Several factors stack together to make stretch marks more common in girls and women. Female puberty involves more dramatic soft tissue changes in a shorter window, particularly breast development and hip widening. Women also carry more subcutaneous fat in the thighs, hips, and buttocks, areas where skin is under chronic tension during growth. Pregnancy later in life adds another major stretching event. And hormonal fluctuations throughout a woman’s life repeatedly affect the skin’s ability to maintain its structural proteins.
None of this means stretch marks indicate a problem. They’re one of the most common skin changes in adolescence, appearing in the majority of girls during puberty regardless of body weight. They aren’t caused by doing anything wrong, and their severity is largely determined by genetics and growth patterns that are outside anyone’s control.