Stretch marks are narrow, streak-like lines that form when skin stretches or shrinks faster than it can adapt. They’re one of the most common skin changes people experience, showing up during pregnancy in an estimated 50 to 90 percent of women, and in 6 to 86 percent of adolescents going through growth spurts. Despite how widespread they are, most people don’t fully understand what’s happening beneath the surface of their skin or what can realistically be done about them.
What Happens Inside Your Skin
Your skin has three main layers. The outermost layer (epidermis) is what you see and touch. Beneath it lies the dermis, a thicker layer packed with collagen and elastin fibers that give skin its strength and bounce-back ability. Stretch marks form in this middle layer.
When skin expands rapidly, the collagen and elastin fibers in the dermis tear and break down. Immune cells rush to the site and release enzymes that dissolve elastic tissue in the mid-dermis. After this breakdown, the body tries to repair the damage by reorganizing collagen and other structural proteins, but the result is thinner, scarred tissue rather than a full restoration. What you see on the surface is a visible line where the dermis has essentially thinned out and lost its normal architecture.
Hormones accelerate this process. Cortisol, produced by the adrenal glands, weakens elastic fibers in the skin. That’s why stretch marks are so common during pregnancy (when cortisol rises significantly), during puberty, and in people using corticosteroid medications. High cortisol impairs the cells responsible for building new collagen, so the skin has less capacity to keep up with rapid stretching.
Early vs. Late-Stage Stretch Marks
Stretch marks go through two distinct phases. In the early stage, they appear as raised, reddish or purplish streaks. The color comes from blood vessels showing through the thinned dermis, and at this point there’s often mild inflammation. These newer marks may feel slightly itchy or tender to the touch.
Over months to years, stretch marks transition into their mature phase. The color fades to white or silvery, the texture flattens, and the skin in those areas can feel slightly depressed or wrinkled compared to the surrounding tissue. At this stage, the blood vessels have receded and the collagen has fully reorganized into scar-like tissue. This distinction matters because treatments are significantly more effective on newer, colored stretch marks than on older, white ones.
Where They Typically Appear
Stretch marks tend to form perpendicular to the direction of skin tension, which is why their location depends on the cause. During pregnancy, they most commonly show up on the abdomen, breasts, and hips. Adolescents going through growth spurts often see them on the thighs, lower back, and buttocks. People who gain muscle quickly through weightlifting frequently develop them on the shoulders, upper arms, and chest. Rapid weight gain from any cause tends to produce stretch marks on the abdomen, flanks, and inner thighs.
Who Gets Them and Why
Genetics clearly play a role, though pinning down the exact mechanism has proven surprisingly difficult. Researchers have looked at specific variations in genes responsible for producing collagen and elastin, but at least one study examining these gene polymorphisms in women with and without stretch marks found no significant differences between the two groups. The genetic predisposition likely involves a more complex interaction of multiple genes affecting skin structure, hormone sensitivity, and repair capacity rather than a single identifiable marker.
Beyond genetics, the strongest risk factors are situations that cause rapid changes in body size. Pregnancy is the most studied: in one study of 110 pregnant women, 61 percent developed stretch marks in at least one location. Adolescent growth spurts are another major trigger, and interestingly, the stretch marks that appear during puberty are more common in males than females, likely because boys tend to grow taller and faster during that period. Rapid weight gain, obesity, and the use of corticosteroid creams or oral steroids also increase risk substantially.
Your baseline skin characteristics matter too. People with less natural skin elasticity, lighter skin, and a family history of stretch marks are more prone. If your mother had significant stretch marks during pregnancy, your odds go up considerably.
Can You Prevent Them?
The honest answer is: only in limited circumstances. The market for stretch mark prevention creams is enormous, but the evidence behind most products is thin. One widely cited clinical trial tested a cream containing Centella asiatica extract (a plant compound that supports collagen production), vitamin E, and collagen-elastin hydrolysates against a placebo. Women using the active cream were about 59 percent less likely to develop stretch marks, but here’s the catch: the benefit only held for women who had already developed stretch marks in a previous pregnancy. For first-time mothers and the general population, there was no evidence of benefit.
Keeping skin well-moisturized may help with comfort and itching as skin stretches, but no cream has been shown to reliably prevent stretch marks across the board. The most effective prevention strategy, where possible, is managing the rate of body size change: gradual weight gain during pregnancy, controlled muscle building, and avoiding rapid fluctuations in body weight.
Treatment Options That Work
No treatment completely erases stretch marks, but several can significantly improve their appearance, especially when started early while marks are still red or purple.
Topical Retinoids
Prescription retinoid creams work by boosting collagen production in the dermis. They’re most effective on newer stretch marks and typically need several months of consistent use to show results. They cannot be used during pregnancy or breastfeeding.
Fractional Laser Therapy
This is currently one of the most effective options for older, white stretch marks. The laser creates microscopic columns of damage in the skin, triggering the body’s wound-healing response and stimulating new collagen formation. A typical course involves three sessions spaced about two months apart. In one study comparing two types of fractional lasers on white stretch marks, 84 percent of patients treated with a 1,550 nm erbium glass laser achieved good to excellent improvement (51 to 100 percent better). A CO2 fractional laser on the same patients’ opposite side produced good to excellent results in 48 percent. Neither laser produced zero improvement in any patient, meaning both moved the needle to some degree.
Microneedling
Microneedling uses fine needles to create controlled micro-injuries in the skin, prompting collagen remodeling. It’s less aggressive than laser therapy and typically requires multiple sessions. Results tend to be moderate, with improvements in both texture and color, particularly for newer stretch marks.
Chemical Peels
Acid-based peels remove outer layers of skin and can improve the texture and color of stretch marks, though they work mainly on the surface and don’t reach the deeper dermal damage as effectively as laser or microneedling approaches.
What Realistic Improvement Looks Like
Even with the best available treatments, stretch marks rarely disappear entirely. The goal is to reduce their visibility by improving color, texture, and the depression of the skin. Newer, red or purple marks respond best to treatment because active inflammation and blood vessel changes can still be reversed. White, mature marks are more resistant because the collagen has already reorganized into stable scar tissue, though fractional laser therapy has shown it can still produce meaningful improvement at this stage.
Most people find that stretch marks fade substantially on their own over time, even without treatment. The reddish-purple phase is temporary. The final result, for most people, is faint silvery lines that are mainly visible up close or in certain lighting. For many, that natural fading process is enough.