Stretch marks rarely show up out of nowhere. In almost every case, they follow a period when the skin is being asked to stretch or shrink faster than it can comfortably adapt — and there are a few very predictable life stages when this happens. Knowing the timeline matters, because most people searching for this information aren’t just curious; they’re trying to figure out whether what they’re noticing on their own skin is normal, and whether there’s still time to act before marks fully form or while they’re still in an early, more treatable stage.

The most common trigger is pregnancy, where stretch marks typically begin to appear from the second trimester onward, usually somewhere between weeks 13 and 21, as the abdomen and breasts expand rapidly to accommodate the growing baby. Puberty is the second major window, when a sudden growth spurt combined with hormonal shifts can cause marks to form on the thighs, hips, and breasts of teenagers almost overnight. Beyond these two natural stages, rapid weight change — whether from dieting, weight gain, or intense strength training that builds muscle mass quickly — can stretch the skin faster than collagen and elastin can keep up. Finally, long-term use of corticosteroid creams or pills is a less obvious but well-documented cause, since these medications thin the skin and weaken its structural support over time.

If you’re noticing any of these changes in your own body right now, here’s what tends to happen just before the marks themselves appear, how to tell how old a mark is just by its color, and what you can actually do about it.

Early signs (what does skin feel like before a mark appears?)

Before a visible line ever shows up, the skin usually gives a few warning signs. The area may become noticeably thinner, take on a slightly pink or reddish tint, and develop an unusual shine or tautness compared to the surrounding skin — this is the dermis being pulled taut faster than it can rebuild itself. Many people also report intense itching or tenderness in specific spots, most often the belly, thighs, hips, or breasts. This itching isn’t random; it’s a direct signal that the skin is under significant mechanical tension, right at the threshold where micro-tears in the collagen and elastin fibers are about to occur. Catching this stage is valuable, because it’s often the last window where consistent moisturizing and hydration can make a measurable difference before a mark sets in.

Types of stretch marks by color (how to tell how old a mark is)

Once a stretch mark appears, its color is actually one of the most useful clues for figuring out how old it is and how treatable it still is.

It’s worth noting that the type of skin you have will determine how quickly a mark transitions from red to white — for some people this happens within months, for others it can take longer, which is part of why treatment timing varies so much from person to person.

If you’ve noticed any of these signs and you’re feeling a bit unsettled about it, that reaction is completely understandable — but it helps to know the full picture before assuming the worst.

Try not to stress about it

If you’ve just spotted your first stretch mark, it’s easy to spiral into worry, but it genuinely helps to put this in perspective. Stretch marks are one of the most common skin changes a body can go through — research shows they affect around 80% of people at some point in their lives, and in pregnancy specifically, approximately 90% of pregnant women develop them. As Dr. Nathan Holt’s clinic explains, stretch marks are a common and natural part of life that appear when the skin stretches or shrinks rapidly, and while many people feel self-conscious about them, they’re a normal reflection of how adaptable the body is.

Just as importantly, stretch marks aren’t a sign that something is medically wrong, and in the vast majority of cases they carry no health risk at all. They’re a cosmetic change, not a symptom of illness. And while they don’t disappear entirely on their own, the deep red or purple tone of a fresh mark does naturally fade and flatten over time as it transitions into that lighter, silvery stage. So if you’re in the early, itchy, reddish phase right now, know that this is simply where the process is — not where it ends.

Our Clinical Solutions

Understanding when stretch marks appear is the first step — knowing what can actually be done about them is the next. At our clinic, we specialize in treating stretch marks at every stage, whether they’re fresh and reddish or older and silvery-white. For early-stage marks, we focus on treatments that calm inflammation and stimulate collagen production while the skin is still responsive. For more established, white stretch marks, we turn to more advanced technology — including laser resurfacing and microneedling — to rebuild the skin’s structure from within and significantly improve texture and tone over a series of sessions.

Every treatment plan we offer is tailored to the type, age, and location of your stretch marks, because what works on a fresh mark on the abdomen isn’t necessarily what works on an older mark on the thighs. If you’d like to learn more about how our approach can help you address your stretch marks, you can explore our dedicated Stretch Marks Treatment page to see the options available and find the right path forward for your skin.