Stretch marks change appearance over time, and which stage yours are in is the single most useful thing to know, because it decides how well treatment will work.
The early stage looks red or purple on light skin and more often dark purple, deep brown or grey-brown on brown and Black skin. The later stage is where the difference is most obvious: on darker skin the faded mark is noticeably lighter than the skin around it, so it can stand out more, not less. Some treatments — particularly aggressive lasers — carry a higher risk of leaving darker or lighter marks in darker skin, which is worth raising before you start.
A line on the skin is not always a stretch mark. See Lookalikes near the bottom of this page.
Stretch marks form when skin is pulled faster than the dermis can adapt to. The dermis is the layer beneath the surface that holds collagen and elastin, the fibres that give skin its strength and spring. When the stretch outpaces them, those fibres tear, inflammation follows, and the skin heals with a thin, differently textured scar. The reason they look flat and slightly sunken is that there is genuinely less structure underneath.
Anything that stretches skin quickly can do it: pregnancy, puberty and growth spurts, gaining or losing weight, and building muscle fast. Hormones matter too, which is why they are so common in pregnancy and in the teenage years — higher cortisol makes collagen weaker and more likely to tear. Long-term strong steroid creams, oral steroids, and conditions like Cushing's syndrome do the same thing. Genetics is a large part of it: if your mother had them, you are much more likely to. And how well hydrated your skin is, or how much cream you used, is not why you have them.
Having stretch marks says nothing about your weight, your discipline or your health. They are a normal thing skin does.
Set expectations before you spend. None of these remove a stretch mark. The most useful thing an at-home routine does is moisturize and buy time while an early mark fades on its own.
Stretch marks are harmless, so seeing someone is optional and mostly about whether you want to treat them. It is worth a visit if:
What the visit gets you: a straight answer about which stage your marks are in, prescription tretinoin if they are still red, and a realistic estimate of improvement before you spend on a package of laser sessions.
One option here has real evidence, and only on early red marks.
This is where measurable improvement comes from, and where the money goes. Expect several sessions and a fainter mark, not a clear one. Match the device to the stage: colour treatments for red marks, texture treatments for white ones.
Red or purple for roughly six to twelve months, then slowly flattening and fading to silver over one to two years. This happens without treatment. Any product used during this window gets credit it may not deserve.
Give it 12 weeks minimum, most studies ran 24. Expect a modest reduction in length and width, not disappearance. Peeling and irritation in the first weeks is normal. Not for use in pregnancy.
Usually three to six sessions, four to six weeks apart. Improvement builds over three to six months after the last session as collagen rebuilds. Typical honest result is a 25 to 50 percent improvement in texture and colour.
Works on the colour, not the texture. Red fades faster than it would on its own. It does nothing for white marks.
Stretch marks never fully disappear. Treated well, they become faint lines most people would not notice unless you pointed them out. That is the realistic best outcome, and no product or device changes it.
Stretch marks cause no medical problems. They do not turn into anything, they do not need monitoring, and they do not affect how the skin functions.
Not every line on the skin is a stretch mark. The ones most often confused: