What Causes Stretch Marks?

What Causes Stretch Marks? 9 Key Triggers You Should Know

If you’ve suddenly noticed red, purple, silvery, or white lines across your abdomen, hips, thighs, breasts, buttocks, arms, or another part of your body, you may be wondering: what causes stretch marks?

The simple answer is that stretch marks usually develop when the skin is forced to expand—or sometimes change—more quickly than its supportive structure can comfortably adapt.

But that’s only part of the story.

Pregnancy, puberty, rapid weight changes, muscle growth, hormones, genetics, medications, and certain medical conditions can all influence what causes stretch marks and why one person develops them while another person experiencing similar body changes does not.

Stretch marks are medically called striae distensae. They represent a form of dermal scarring rather than merely a surface discoloration. When the skin changes rapidly, alterations can occur in the collagen and elastic tissue that provide its strength and flexibility.

That distinction matters because effective treatment usually needs to address more than skin color alone.

At En Santé Med, the goal of stretch mark evaluation is therefore not simply to ask, “How do we erase this line?” Instead, a more useful approach considers the age, color, texture, depth, location, skin type, and underlying cause of the stretch marks before determining whether treatment may improve their appearance.

Here’s what you should know.

What Exactly Are Stretch Marks?

Stretch marks are narrow bands or streaks that develop within the skin after structural changes occur in the dermis.

The American Academy of Dermatology describes a stretch mark as a type of scar that can form when the skin stretches or shrinks rapidly. Sudden change can disrupt collagen and elastin, two important components that help support normal skin structure. As the skin repairs itself, the visible stretch mark can remain.

Stretch marks aren’t dangerous in most cases.

They also aren’t evidence that someone hasn’t taken good care of their skin.

In fact, extremely common biological events—including adolescence and pregnancy—are among the most frequent circumstances associated with their development.

Why Stretch Marks Are Actually a Type of Scar

Normal skin contains an organized framework of collagen, elastin, fibrillin, and other extracellular matrix components.

These structures allow the skin to maintain strength while still remaining flexible.

When mechanical stress, hormonal influences, genetic predisposition, or other factors alter this connective-tissue framework, microscopic structural changes can occur within the dermis.

Research suggests that stretch marks involve alterations in collagen and elastic fibers rather than a simple “overstretching” of normal skin. Their development is therefore considered multifactorial.

That helps explain one frustrating observation: two people can undergo similar pregnancy or weight changes, yet only one develops significant stretch marks.

Striae Rubrae vs. Striae Albae

Stretch marks also change over time.

Striae rubrae are relatively new stretch marks. Depending on skin tone, they may appear:

• Red
• Pink
• Purple
• Reddish-brown
• Dark brown

Early stretch marks may occasionally feel slightly raised or itchy.

As they mature, they generally become flatter, lighter, and more depressed. These older marks are often called striae albae and may look white or silvery.

This distinction isn’t merely cosmetic.

The biological characteristics of an early vascular stretch mark differ from those of an older, pale, atrophic scar. Consequently, the ideal treatment strategy may also differ.

What Causes Stretch Marks? The Biology Behind Them

So, what causes stretch marks beneath the surface?

Think of healthy skin as a flexible support system.

Collagen contributes strength. Elastin contributes elasticity. Other proteins and extracellular matrix structures help organize and support the dermis.

When the body changes quickly, the skin must remodel rapidly.

If that remodeling process can’t keep pace—or if the tissue is particularly susceptible because of genetics or hormonal influences—the architecture of the dermis can change.

Stretch marks may then appear.

Collagen and Elastin Changes

The process is considerably more sophisticated than skin simply being “pulled apart.”

Published reviews of striae distensae describe alterations in the extracellular matrix, including collagen, elastin, fibrillin, and fibronectin.

This is one reason many modern treatments focus on collagen remodeling and controlled skin renewal rather than trying to bleach, cover, or superficially exfoliate the mark.

The objective isn’t literally to glue damaged fibers back together.

Instead, certain procedures attempt to stimulate a wound-healing response that encourages healthier remodeling within and around the stretch mark.

Why Some People Develop Them and Others Don’t

One of the most common questions patients ask is:

“Why did I get stretch marks when someone else didn’t?”

There isn’t one answer.

Your susceptibility appears to depend on a combination of:

Genetics + hormonal environment + speed of body change + mechanical stress + skin structure + medications + underlying medical conditions.

Family history is particularly important. The American Academy of Dermatology notes that someone may have a greater risk if other members of their family develop stretch marks.

In other words, you can do many things “right” and still develop them.

1. Pregnancy

Pregnancy is one of the best-known answers to what causes stretch marks.

As the abdomen expands, the skin must adapt to substantial changes over a relatively short period.

But stretching isn’t the only factor.

Pregnancy produces profound hormonal changes that may also influence connective tissue and the skin’s response to mechanical stress.

Stretch marks during pregnancy are often known as striae gravidarum.

Common locations include the:

• Abdomen
• Breasts
• Hips
• Buttocks
• Upper thighs

The Mayo Clinic notes that stretch marks are particularly common during pregnancy and often become noticeable during the later stages.

Why Pregnancy Stretch Marks Develop

Several factors may work together.

The abdominal wall expands. Breast volume may increase. Weight changes occur. At the same time, pregnancy-associated hormonal changes affect connective tissues throughout the body.

Genetic susceptibility may further influence who develops stretch marks and how extensive they become.

This means pregnancy stretch marks shouldn’t simply be viewed as evidence that someone’s skin “wasn’t moisturized enough.”

Moisturizing can certainly improve comfort and dryness, but preventing structural dermal change is another matter entirely.

2. Puberty and Rapid Growth

Adolescence represents another classic period when people ask why stretch marks happen.

During a growth spurt, height, weight, skeletal dimensions, breast development, and muscle mass can change quickly.

The skin must adapt to all of it.

Stretch marks during puberty commonly occur on the:

Girls: breasts, hips, thighs, buttocks, and lower back.

Boys: shoulders, upper arms, thighs, back, and other areas undergoing rapid growth.

This can happen in otherwise healthy, athletic teenagers at a normal weight.

Both the American Academy of Dermatology and Mayo Clinic recognize rapid growth during adolescence as a common setting for stretch-mark formation.

So when teenagers develop stretch marks, weight alone should never automatically be blamed.

Growth itself may be the trigger.

3. Rapid Weight Gain

Rapid weight gain is another frequent answer to what causes stretch marks.

When fat volume increases rapidly beneath the skin, the surrounding tissue must accommodate the expansion.

The faster the volume change occurs, the greater the remodeling demand placed on the skin.

That doesn’t mean every person who gains weight will develop stretch marks.

Genetics, hormones, age, skin structure, and the amount and rate of weight change all matter.

Areas frequently affected include the abdomen, hips, thighs, breasts, buttocks, and upper arms.

Gradual body changes may allow the skin more time to adapt, although there is no guaranteed method of preventing stretch marks altogether.

4. Rapid Weight Loss

Many people associate stretch marks exclusively with gaining weight.

That’s incomplete.

Rapid weight change in either direction is associated with striae distensae. Medical references recognize both rapid weight gain and weight loss as common settings in which stretch marks may be observed.

Importantly, losing weight doesn’t necessarily mean new marks appeared because the skin was “stretched” during weight loss.

Sometimes stretch marks that developed during previous tissue expansion simply become more visible once the surrounding volume decreases.

Changes in skin laxity can make existing textural irregularities easier to see as well.

Do GLP-1 Medications Directly Cause Stretch Marks?

This is increasingly relevant as more people experience significant weight loss with medications in the GLP-1 class.

It is more accurate to separate the medication from the body change.

Stretch marks aren’t simply a predictable direct effect of using a GLP-1 medication. Rather, substantial or rapid changes in body volume may make previously existing stretch marks more visible or contribute to conditions in which the skin’s structural limitations become more noticeable.

For patients pursuing major weight reduction, skin quality should therefore be considered as part of the broader body-composition journey rather than only after goal weight has been reached.

5. Rapid Muscle Growth and Weight Training

Stretch marks aren’t limited to pregnancy or changes in body fat.

Rapid muscle hypertrophy can create them too.

This commonly occurs around:

• Shoulders
• Upper arms
• Chest
• Back
• Thighs

People who build substantial muscle rapidly may notice reddish or purplish streaks near areas undergoing the greatest enlargement.

The American Academy of Dermatology specifically lists rapid muscle growth associated with weight training among the circumstances in which stretch marks may develop.

Anabolic steroid exposure may add another layer of risk because steroid-related hormonal effects can affect the skin’s connective tissue.

For recreational athletes and bodybuilders, the underlying issue isn’t that exercise damages the skin. It is the speed and magnitude of tissue expansion, potentially combined with hormonal influences.

6. Hormonal Changes

Understanding what causes stretch marks requires understanding hormones.

The skin is hormonally responsive tissue.

Hormonal fluctuations can influence fibroblasts, collagen metabolism, elasticity, inflammation, and connective-tissue remodeling.

This helps explain why stretch marks cluster around major hormonal transitions such as puberty and pregnancy.

Cortisol and Stretch Marks

Cortisol deserves particular attention.

The Mayo Clinic notes that cortisol may influence stretch-mark development because elevated cortisol can weaken elastic fibers within the skin.

This connection becomes especially relevant when stretch marks occur in association with prolonged corticosteroid exposure or disorders characterized by excessive cortisol activity.

However, developing ordinary pregnancy, puberty, or weight-related stretch marks doesn’t mean someone has abnormal cortisol levels.

The clinical context matters.

7. Genetics

Some people simply have a greater biological predisposition toward developing stretch marks.

Family history appears to matter.

You may have watched a parent, sibling, or other close relative go through pregnancy without developing noticeable stretch marks—and assumed you would experience the same thing.

Or the opposite may happen.

Genetic susceptibility appears to influence collagen and extracellular-matrix biology, although the genetics of striae distensae aren’t completely understood.

This explains why comparing your skin with someone else’s can be misleading.

Different bodies have different structural starting points.

8. Corticosteroid Medications

Long-term corticosteroid exposure can sometimes contribute to stretch marks.

This includes certain topical corticosteroids as well as systemic corticosteroid exposure.

Corticosteroids can influence collagen and connective tissue, potentially making the skin more susceptible to striae.

The American Academy of Dermatology specifically notes that prolonged use of topical corticosteroids may contribute to stretch-mark formation.

This doesn’t mean prescribed corticosteroids should suddenly be stopped.

They are medically important treatments for numerous conditions.

Instead, unusually prominent stretch marks in someone using corticosteroid medication are worth discussing with the healthcare professional managing that therapy.

9. Certain Medical and Connective-Tissue Conditions

Most stretch marks are benign.

Occasionally, however, what causes stretch marks can involve an underlying medical condition.

Medical literature associates striae with disorders including:

Cushing syndrome, which involves excessive cortisol activity.

Marfan syndrome, a connective-tissue disorder.

Other circumstances involving altered connective-tissue structure or endocrine function may also affect susceptibility.

This doesn’t mean stretch marks should automatically cause alarm.

They are extraordinarily common.

However, very widespread, unusually large, rapidly appearing, or otherwise atypical stretch marks—particularly when accompanied by unexplained bruising, muscle weakness, significant metabolic changes, or other systemic symptoms—deserve medical evaluation rather than purely cosmetic treatment.

Where Do Stretch Marks Usually Appear?

Stretch marks tend to occur where body volume changes most rapidly.

Common locations include the abdomen, breasts, hips, buttocks, thighs, upper arms, shoulders, and lower back.

Their pattern can sometimes provide clues about what causes stretch marks in a particular patient.

Pregnancy may predominantly affect the abdomen and breasts.

Puberty may involve the thighs, hips, breasts, back, or shoulders.

Rapid muscle development may produce marks near the shoulders, chest, or arms.

Weight fluctuations can produce marks across several body areas.

This is why a good stretch-mark consultation should examine the overall pattern rather than treating every line exactly the same way.

Why Are Some Stretch Marks Red and Others White?

Color often tells us something about the age and activity of the stretch mark.

Newer stretch marks—striae rubrae—may look pink, red, purple, dark brown, or reddish-brown depending on the person’s natural skin pigmentation.

Older stretch marks—striae albae—typically become lighter and more scar-like.

The difference matters because early striae can contain a more noticeable vascular or inflammatory component, whereas mature white stretch marks tend to behave more like established atrophic scars.

That’s one reason patients shouldn’t assume that the same laser setting or procedure should be used for every stretch mark.

The stage of the scar matters.

So does skin tone.

So does location.

And so does the patient’s tolerance for downtime.

Can Stretch Marks Be Prevented?

Unfortunately, there is no guaranteed method.

Maintaining relatively gradual changes in body weight where medically appropriate, supporting general skin health, avoiding unnecessary corticosteroid exposure, maintaining adequate nutrition, and keeping skin moisturized are sensible measures.

But genetics and hormones cannot simply be moisturized away.

This is an important point because people—particularly women after pregnancy—are often made to feel that they somehow “failed” to prevent stretch marks.

That’s not supported by how stretch marks actually develop.

The AAD notes that several popular topical approaches haven’t consistently prevented stretch marks in research. Some evidence suggests that preparations containing centella or hyaluronic acid may have preventive potential, but results aren’t absolute.

Do Creams and Oils Actually Prevent Stretch Marks?

Cocoa butter, almond oil, olive oil, vitamin E, and similar products are frequently promoted for stretch-mark prevention.

They may moisturize the skin and make it feel more comfortable.

That isn’t the same as proving that they prevent striae.

According to the American Academy of Dermatology, research has not shown common ingredients such as cocoa butter, almond oil, olive oil, and vitamin E to consistently prevent stretch marks.

Moisturizer still has value.

Healthy, comfortable skin is a good thing.

The key is maintaining realistic expectations.

Can Stretch Marks Go Away Naturally?

Stretch marks frequently fade, especially during the months and years after they first appear.

But fading is different from disappearing.

A mature stretch mark represents structural change within the dermis, and the American Academy of Dermatology describes stretch marks as permanent scars, although treatment may make them less noticeable. Mayo Clinic similarly notes that they often fade but may never disappear completely.

This distinction helps establish realistic expectations for treatment.

The goal isn’t necessarily “zero evidence that a stretch mark ever existed.”

A more medically realistic objective is improvement in:

Color, texture, depth, width, contrast, and overall visibility.

When Should You See a Medical Professional?

Most stretch marks don’t require medical treatment.

Consider an evaluation when stretch marks:

• Appear suddenly without an obvious explanation
• Develop across unusually large areas
• Become particularly wide or prominent
• Occur during prolonged corticosteroid use
• Appear with other unexplained physical changes
• Cause significant cosmetic concern
• Need to be distinguished from another skin condition

Mayo Clinic specifically advises medical evaluation when stretch marks affect large areas or when someone is concerned about their cause.

A cosmetic treatment plan should never replace an appropriate medical evaluation when the pattern is unusual.

How Are Stretch Marks Treated?

Once patients understand what causes stretch marks, the next question is usually:

“Can you actually treat them?”

Yes—but “treat” is a better word than “erase.”

Stretch marks can often be made less noticeable, although no currently available treatment can guarantee complete removal.

Options may include topical therapies for selected early stretch marks, microneedling, radiofrequency-based treatments, resurfacing procedures, and laser therapy.

The AAD identifies laser treatment, radiofrequency, microdermabrasion, ultrasound, chemical peels, and other physician-performed procedures among methods used to reduce the appearance of stretch marks. Treatment may sometimes combine modalities.

The right approach depends heavily on the individual stretch mark.

Laser Stretch Mark Treatment

Laser therapy can be particularly useful because modern platforms allow clinicians to address different components of stretch marks rather than treating every case identically.

Treatment may focus on:

Vascularity: reducing the red or purple appearance of early striae.

Texture: resurfacing irregular or depressed tissue.

Collagen remodeling: stimulating controlled tissue repair.

Skin quality: improving the transition between normal surrounding skin and the stretch mark.

Fotona describes its stretch-mark treatment approach as combining Er and Nd wavelengths, with treatment strategies designed to address both scar characteristics and, where appropriate, vascular components while stimulating collagen remodeling.

Its LineLase approach also combines non-ablative Er thermal stimulation with ablative or fractional Er resurfacing to address laxity, texture, and the scar characteristics of striae.

Individual protocols, number of sessions, intensity, downtime, and results vary.

Why Treatment Should Be Customized to the Stretch Mark

A red stretch mark that appeared six months ago isn’t biologically identical to a white stretch mark that has been present for 15 years.

That distinction can influence whether treatment emphasizes:

Stretch Mark Feature	Potential Treatment Objective
Red/purple coloration	Address vascular contrast
White/silver coloration	Improve texture and blending
Depressed texture	Encourage remodeling/resurfacing
Wide atrophic striae	Improve texture and visual depth
Associated skin laxity	Support collagen remodeling
Darker skin type	Carefully control inflammation and pigment risk
Recent stretch marks	Consider earlier intervention when appropriate
Mature stretch marks	Focus on realistic scar remodeling

This personalized approach is particularly important for patients with more melanin-rich skin because unnecessary inflammation can increase the risk of post-inflammatory hyperpigmentation.

Treatment parameters therefore shouldn’t be selected from a one-size-fits-all menu.

Stretch Mark Treatment at En Santé Med

At En Santé Med, stretch-mark treatment can be approached as a skin-restoration problem rather than simply a surface blemish.

That starts by determining:

What caused the stretch marks?

Are they relatively new or mature?

Are they predominantly vascular, textural, atrophic, or mixed?

How does the surrounding skin compare with the stretch mark?

What is the patient’s skin type?

Is there skin laxity in addition to striae?

How much downtime is acceptable?

Those questions help guide the treatment strategy.

For appropriate candidates, customized laser-based protocols may be considered to stimulate collagen remodeling, improve surface texture, and reduce the visual contrast between stretch marks and surrounding skin.

Rather than promising “stretch mark removal,” En Santé Med’s goal is to pursue meaningful, progressive improvement while respecting the biology of scar tissue and the patient’s individual skin characteristics.

Patients considering stretch mark treatment in McLean, Northern Virginia, or the greater Washington, DC area can benefit from an assessment that looks beyond the mark itself and considers the condition of the entire treatment area.

Frequently Asked Questions About Stretch Marks

1. What causes stretch marks most commonly?

The most common causes are pregnancy, puberty, rapid weight gain or loss, and rapid muscle growth. Genetics and hormonal factors influence susceptibility, while corticosteroid exposure and certain medical disorders can occasionally contribute.

2. Are stretch marks caused by gaining weight?

Weight gain is one possible cause, but it isn’t the only one.

Stretch marks can occur during pregnancy, adolescence, muscle building, and weight fluctuations. They can even occur in people with relatively stable body weight.

That’s why asking what causes stretch marks requires more context than simply looking at someone’s weight.

3. Why did I get stretch marks even though I didn’t gain much weight?

Genetics, puberty, hormones, pregnancy, muscle development, corticosteroid exposure, and underlying connective-tissue characteristics can all influence stretch-mark formation.

The speed and location of body change may also matter more than the absolute number of pounds gained.

4. Do stretch marks mean the skin has torn?

Not in the sense of a visible cut or open wound.

However, stretch marks involve structural changes within the dermal connective tissue, including alterations affecting collagen and elastic fibers. That’s why they are medically considered a form of dermal scar.

5. Do stretch marks disappear after pregnancy or weight loss?

They frequently become less noticeable.

Early red, purple, or darker stretch marks often fade toward lighter or silvery shades over time. However, the structural mark may remain.

Treatment can sometimes improve its appearance further, but complete elimination cannot be guaranteed.

6. Is it better to treat stretch marks while they’re still red?

Early stretch marks may offer different treatment opportunities because they haven’t yet matured into pale striae albae.

The Fotona LineLase clinical information, for example, notes that earlier striae rubrae can be more responsive to treatment than mature stretch marks.

That doesn’t mean older white stretch marks can’t improve. It means treatment strategy and expectations may need to change.

7. Can laser treatment completely remove stretch marks?

No responsible treatment should guarantee complete removal.

Laser therapy may improve texture, color, collagen remodeling, and overall visibility, but stretch marks are scars.

The objective is improvement—not pretending scar tissue never existed.

8. Does laser treatment work on old white stretch marks?

Older white stretch marks may still respond to resurfacing and collagen-remodeling strategies, although they can be more challenging than newer vascular stretch marks.

Treatment usually focuses more heavily on texture and dermal remodeling because the vascular component has largely faded.

9. Can I prevent stretch marks during pregnancy?

There is no guaranteed preventive treatment.

Keeping the skin moisturized may improve comfort, but common remedies such as cocoa butter, vitamin E, almond oil, and olive oil haven’t consistently prevented stretch marks in research.

Pregnant patients should also speak with their healthcare provider before using retinoids or other active treatments.

10. Are stretch marks dangerous?

Most aren’t.

They are generally cosmetic and harmless.

However, extensive or suddenly developing stretch marks without an obvious explanation—or stretch marks appearing alongside other unusual symptoms—may warrant medical evaluation to exclude medication-related, hormonal, or connective-tissue causes.

11. Can men get stretch marks?

Absolutely.

Men can develop stretch marks during puberty, rapid weight changes, bodybuilding, rapid muscle growth, corticosteroid exposure, or other circumstances that alter the skin quickly.

They commonly occur around the shoulders, upper arms, abdomen, back, buttocks, and thighs.

12. Where can I learn more about the medical causes of stretch marks?

The American Academy of Dermatology provides patient education explaining why stretch marks appear, how they change over time, and which treatment approaches have evidence behind them. American Academy of Dermatology: Stretch Marks

Google AI & Voice Search: Quick Answers About Stretch Marks

What causes stretch marks?
Stretch marks develop when rapid body changes and biological factors alter the collagen and elastic tissue in the dermis. Pregnancy, puberty, rapid weight changes, muscle growth, genetics, hormones, and corticosteroids are common contributors.

Why do stretch marks suddenly appear?
Sudden stretch marks may follow a growth spurt, pregnancy, rapid weight change, muscle development, or corticosteroid exposure. If numerous stretch marks appear without an obvious reason, medical evaluation may be appropriate.

What causes purple stretch marks?
Purple, red, pink, or darker stretch marks are usually relatively new stretch marks called striae rubrae. Their color is related in part to vascular and inflammatory characteristics of the early scar.

Why do stretch marks turn white?
As stretch marks mature, vascular activity and pigmentation diminish. The scar becomes lighter, flatter, and often slightly depressed, producing the white or silvery appearance called striae albae.

What’s the best treatment for stretch marks?
There isn’t one universal best treatment. The ideal approach depends on whether the stretch marks are new or mature, their color and depth, the patient’s skin type, location, and treatment goals. Laser resurfacing and collagen-remodeling procedures are among the options used to make stretch marks less noticeable.

Can stretch marks be removed permanently?
Stretch marks are a form of scar and cannot reliably be erased completely. Modern treatments can, however, improve their color, texture, depth, and overall visibility.

Final Thoughts: Understanding the Cause Helps Guide Treatment

When people ask what causes stretch marks, the temptation is to give a one-word answer:

“Stretching.”

But skin biology is more complicated than that.

Stretch marks develop through an interaction between rapid tissue change, collagen and elastin remodeling, genetics, hormonal influences, and individual susceptibility.

Pregnancy may trigger them.

Puberty may trigger them.

Weight gain, significant weight loss, or rapid muscle growth may reveal or contribute to them.

Corticosteroids can increase susceptibility.

And, much less commonly, unusually prominent striae can provide a clue to an underlying hormonal or connective-tissue condition.

Most importantly, stretch marks aren’t simply a superficial problem.

They are scars occurring within living, dynamic tissue.

That is why modern stretch-mark treatment should move beyond the old expectation of simply applying a cream and hoping the lines disappear.

At En Santé Med, treatment philosophy can instead focus on understanding the stretch mark’s cause, age, color, texture, depth, surrounding skin quality, and individual skin type before selecting a restorative strategy.

For appropriate candidates, advanced laser approaches may help stimulate collagen remodeling, resurface irregular texture, address vascular coloration in newer stretch marks, and make striae blend more naturally with the surrounding skin.

The goal isn’t artificial perfection.

It’s healthier-looking, smoother, more uniform skin—and a treatment plan grounded in the biology of how stretch marks actually form.

Considering Stretch Mark Treatment?

If stretch marks on the abdomen, thighs, hips, buttocks, breasts, arms, or other areas are bothering you, a personalized consultation can determine whether laser skin remodeling or another treatment approach is appropriate.

Schedule a consultation with En Santé Med to explore a customized stretch-mark treatment plan based on your skin, your scar pattern, and your goals.

Medical note: This article is for educational purposes and doesn’t substitute for individualized medical diagnosis or treatment. New, widespread, or unexplained stretch marks should be evaluated by an appropriate healthcare professional.