What they are
Stretch marks, known in medical language as striae, are streaks or bands that appear in the skin, most often on the abdomen, hips, thighs, buttocks, breasts, lower back and upper arms. They are a form of scarring in the middle layer of skin, called the dermis, which contains the collagen and elastin fibers that give skin its strength and flexibility. When these fibers are stretched or disrupted, the skin can develop marks that remain visible.
They are not harmful in themselves, are not a sign of poor health, and are very common. Exactly how many people have them is hard to state, as figures vary between studies and populations, but it is widely accepted that a large share of people have at least some during their lives.
Why they happen
The exact mechanism is not fully understood. Researchers generally agree that several factors are involved:
- Rapid growth or stretching of the skin. Growth spurts in puberty, pregnancy, and quick gains in weight or muscle are the best-known situations.
- Hormones. Changes in hormone levels, including those during puberty and pregnancy, are thought to affect the skin’s fibers. Excess levels of certain hormones, whether from a medical condition or from some long-term medications, can also contribute.
- Genetics. Family history seems to matter. Some people develop them with little change in body size, while others with large changes do not.
- Certain medical conditions and medications. Prolonged use of strong corticosteroid creams or pills and some health conditions have been linked to stretch marks. Anyone concerned about the effects of a medication should speak to the doctor who prescribed it rather than stop it unilaterally.
Because several factors interact, it is not possible to predict who will get stretch marks or to guarantee prevention.
How they look and change
Stretch marks often start as slightly raised or flat lines that are pink, red, purple or brownish, depending on skin tone, and may feel itchy or slightly tender. Over months to years they usually become paler, flatter and sometimes silvery or white, and the surface may feel slightly different from the surrounding skin. They rarely disappear completely, but many become much less noticeable with time.
The appearance varies by person. Size, number and color are influenced by skin tone, how quickly the stretching occurred and individual healing. Visible marks on dark or light skin look different, and neither is better or worse medically.
Where they connect to other topics
Stretch marks are closely linked with other body changes discussed on this site. Rapid weight change can leave them behind, as can building muscle quickly. During pregnancy, many people notice them, and the topic belongs among pregnancy considerations that also relate to skin and body art. They differ from the skin looseness that sometimes follows large weight loss, which involves the skin’s elasticity rather than lines in the dermis. They are also different from raised scars such as keloids, which are caused by an overgrowth of scar tissue after injury.
What about creams and treatments?
Many products are marketed for preventing or fading stretch marks. The research evidence is generally limited or mixed, and it is difficult to say with confidence that any given cream, oil or device will work. Moisturizing can make skin feel more comfortable and may help with itching, but it is not a guaranteed way to prevent marks.
For those who want to reduce their appearance, dermatologists can discuss options. These may include prescription creams, light-based or laser approaches, microneedling and other procedures. Results vary, and no treatment is guaranteed to remove them. Some options are not suitable during pregnancy or while breastfeeding, and some carry risks such as irritation, pigment changes or scarring. A qualified, licensed professional should perform any procedure, and the decision is best made after a consultation. This website does not recommend specific treatments or providers.
Living with them
Many people see stretch marks as an ordinary part of a body that has grown, carried a child or changed over time. Others feel self-conscious about them, particularly when media images show only smooth, edited skin. Feelings on this range widely and neither is wrong. If worry about them is affecting your confidence or daily life, talking with a doctor or counselor can help, and a growing amount of social media content shows unretouched skin, which some people find reassuring.
Some people choose to cover or alter the appearance of stretch marks with cosmetics, temporary products or tattoos. Tattooing over scarred skin raises extra considerations because scar tissue can take ink differently, and it should be discussed with an experienced, licensed artist and, if there is any doubt, with a doctor.
When to ask a doctor
Stretch marks are usually harmless, but it can be worth seeing a doctor if:
- They appear suddenly and in large numbers without an obvious cause such as growth, pregnancy or weight change.
- They come with other symptoms such as unusual weight gain around the middle, easy bruising, muscle weakness, or changes in menstrual cycles, since these may point to a hormonal condition that deserves evaluation.
- The skin is very itchy, painful, broken or infected.
- You are using steroid creams or other medicines and have noticed skin thinning or marks.
- The marks are causing significant distress.
In most cases, a doctor can reassure you and, where appropriate, discuss options. Stretch marks are common, and having them says nothing about your health, discipline or worth.