Stretch Marks 101: What Causes Them (and How to Treat Them, if You Want)

Over the course of a single year in middle school, my chest grew from barely needing a bra to full-on D cups. It was remarkable, to say the least. But with my newfound cleavage came a less welcome gift: stretch marks, covering both breasts in a crepe-y texture and pink-hued lines.

What I feared ruined my newfound bosoms were actually totally normal: Estimates suggest that up to 70 percent of adolescent girls, 40 percent of adolescent males, and 90 percent of pregnant women develop stretch marks. Stretch marks are a part of life, and as I've gotten older (and, to be fair, as they've faded into a barely noticeable white hue), they've bothered me less and less.

But I still had questions: Why exactly do we get stretch marks? And are they as permanent as they seem? The answers, it turns out, aren't so simple. Read on for everything you need to know about stretch marks, straight from board-certified dermatologists Nicole Hayre, MD, Sarah Boyce Sawyer, MD, and Tiffany Clay, MD.

What Causes Stretch Marks?

Before we get into what causes stretch marks, let's go over what stretch marks are. According to Sawyer, "stretch marks, also known as striae, are a type of scar that looks like indented streaks on the skin." Commonly found around the abdomen, hips, buttocks, breasts, and thighs, stretch marks vary in color, size, and texture.

To get slightly more scientific about it, "stretch marks are areas in the skin which have broken down or thinned under tensile pressure," says Hayre. When collagen (which is the building block of the skin) is reduced or damaged in a given area, the skin appears atrophic or thin and allows for tears in the dermis.

Before stretch marks begin to emerge, the skin can appear thin and pink. It might also feel irritated or itchy. As the marks develop, they often appear as wrinkly, raised streaks that are typically pink, red, purple, blue, or brown, depending on skin color. Over time, these streaks flatten and fade into a white-silver color. This process often takes many years.

Stretch marks appear when the body (or a certain area of the body) grows so rapidly that the skin cannot make enough collagen to keep up with this growth, according to Clay. This accelerated rate of skin stretching causes collagen and elastin (which are fibers that support the skin's elasticity) to rupture. As those ruptures heal, scars may appear in the form of stretch marks, says Sawyer.

But when exactly does this phenomenon happen? Common causes of stretch marks include:

• Rapid weight gain: Putting on a lot of weight in a relatively short amount of time stretches the skin and can result in stretch marks.
• Pregnancy: Between 50 percent to 90 percent of women who are pregnant report stretch marks occurring during or after birth.
• Puberty and growth spurts: Rapid growth and weight gain are fairly typical when going through puberty, often leading to stretch marks.
• Sudden, rapid muscle growth: Those who quickly build muscle mass (think bodybuilders and weight trainers) are more prone to stretch marks, according to Clay.
  

Who Is Most At Risk for Stretch Marks?

Absolutely anyone can develop stretch marks, making them incredibly common. While everyone can develop stretch marks, it's important to note that not everyone does. On the flip side, as Hayre points out, sometimes the development of stretch marks is unavoidable.

That being said, some factors do increase your likelihood of getting stretch marks, says Sawyer. These include being female, using corticosteroids, having a genetic disorder like Cushing's Syndrome, and having a family history of stretch marks (both Sawyer and Clay point to the connection between stretch marks and genetics).

People might also be more at risk for certain types of stretch marks than others. The most common classifications of stretch marks are as follows:

• Striae rubrae: Pink or red stretch marks.
• Striae albae: White stretch marks,
• Striae gravidarum: Stretch marks that occur as a result of pregnancy.
• Striae caerulea: Dark blue or purplish stretch marks (which are more commonly seen on darker complexions).
• Striae nigra: Black or dark gray-colored stretch marks (which are also more common on darker complexions).
• Striae atrophicans: Thinned skin associated with stretch marks, which often develops in those with Cushion's Syndrome or after a surgical procedure.
  

Can You Treat Stretch Marks at Home?

Like other scars, stretch marks tend to fade over time. But because they are permanent, they may remain slightly visible. "On lighter skin tones, stretch marks may appear red when they initially appear and then lighten to a pale white over time," explains Clay. "However on darker skin tones, this redness on fresh stretch marks may take on a purplish color before eventually lightening."

There are many ways to treat stretch marks at home and accelerate that fading process—though results are a bit of a mixed bag with no definitive cure-all. All three experts agree it's best to treat stretch marks when they first appear.

Sawyer is a fan of SkinCeuticals' Body Tightening Concentrate ($82). The cooling fluid body treatment helps tighten, smooth, and firm the appearance of skin. Clay suggests a similar product: Bush Balm's Tush Firming Cream ($36), which works to firm the skin and improve elasticity.

Meanwhile, Hayre says consistent use of a retinol body lotion at home can help build collagen back up in the affected area. Byrdie favorites include the Retinol Skin-Smoothing Body Treatment ($29) by Paula's Choice and PH Factor 5.5's Retinol & Ferulic Acid Cream ($14).

In-Office Treatments for Stretch Marks

For those looking for more definite results (and willing to shell out the big bucks), there are a number of in-office treatments that improve the appearance of stretch marks.

For pink- or red-colored stretch marks, Hayre suggests IPL or laser treatments, which can reduce redness and increase collagen production. Clay notes that this treatment is best for lighter skin tones. A series of microneedling treatments will work on all skin types and can help improve texture and discoloration. And all three doctors point to radio-frequency treatments to stimulate collagen production and improve the appearance of wrinkled, sagging skin.

Unfortunately, all of these in-office treatments are fairly expensive and require several rounds of treatment (usually around four to six) over the course of several months to really see a difference.

Can You Prevent Stretch Marks?

Generally speaking, you can't prevent stretch marks. But there are a few ways to reduce the likelihood of them developing (though, again, that doesn't mean they won't occur altogether). Keeping weight stable, or at least avoiding rapid, considerable changes in weight or size, can help—though we understand that can be easier said than done, plus potentially avoiding stretch marks is pretty much the least compelling reason to maintain a stable weight. Sawyer says that keeping the body hydrated and nourished can also help.

The Final Takeaway

Stretch marks are similar to cellulite: Even though the overwhelming majority of women have one of the two (if not both), years of demonization and shame have left many of us feeling embarrassed and at fault for these completely natural occurrences.

Here's the good news: While you can't totally get rid of either, there are ways to minimize the appearance if you so choose. At the end of the day, we're not here to judge. Stretch marked or not, we embrace body positivity through and through.

So love those stretch marks and let them shine, or go ahead and slather on some retinol to minimize them. Either way, we think you look great.