Patient Resource

More than skin deep: how are stretch marks formed?


Stretch marks are an extremely common problem particularly in women.  And while they are usually benign, their unsightly appearance is the source of cosmetic concern for a lot of people. As stretch marks effect so many people there are countless old wives’ tales surrounding the cause as well as plenty of tips to prevent or even get rid of them for good.

Lathering yourself with olive oil, cocoa butter or Vicks vapour along with vigorous massage has been tried and tested by many to help reduce the severity of their stretch marks.   But does it actually work or are you wasting time and money? We’re here to try and dispel the myths surrounding stretchmarks and give you all the facts!

What are stretch marks?

Medically known by the names of striae distensae, SD, striae, striae atrophicans and striae gravidarum, stretch marks are defined as dermal scars or lesions on the outermost layer of the skin.  They present themselves as pink, red or purple indented streaks often on the hips, abdomen, breasts, upper arms, thighs or buttocks.  Over time stretchmarks tend to flatten and fade to translucent white or grey pale marks.

While both men and women are affected by stretch marks around 70 percent of adolescent girls develop the condition during puberty compared to 40 percent of boys. Those at higher risk of developing stretch marks include:

  • Adolescents during growth spurts
  • Pregnant women
  • Body-builders
  • Obese or overweight people

Stretch marks also are common in those people with prolonged use of oral or topical corticosteroids.  Widespread stretch marks can also be seen in patients with genetic disorders such as Marfan or Ehlers-Danlos syndrome as well as Cushing’s syndrome and adrenal gland disease.

According to the American Osteopathic college of Dermatology females are predisposed to develop stretch marks in the breasts.  While males on the other hand tend to develop the condition along the lower back, armpits and upper arms.

What causes stretch marks?

Stretch marks are formed is the areas of the body where the skin is subjected to continuous stretching.  The skin is divided into three main layers: the subcutaneous or hypodermis (deepest layer), dermis (middle layer) and the epidermis (the outer layer).


Stretch marks are formed within the dermis.  The rapid stretching of the connective tissue due to sudden growth or weight gain damages the dermal tissue atrophy and causes thinning of the outer layer.  This allows the deeper skin layers to be revealed forming the unsightly streaks long the surface.

When the body grows, the connecting fibres of the dermis naturally stretch slowly.  However with rapid growth, these fibres are overstretched and tear.  This inflammatory reaction within the skin is the responsible for the stretch mark’s red or purple tone.  When viewed under a microscope, the tissue affected by stretch marks resembles that of a scar due to the changes in the collagen fibre appearance.

Associated factors for stretch mark occurrence

Various risk factors have been linked to the occurrence of stretch marks in men and women.  The reality is that there is no one cause of stretch marks.  Associated factors to their occurrence are believed to include:

  • Maternal age
  • Genetic factors and inherited defects
  • Hormonal changes
  • BMI
  • Gestational age
  • Birth weight of infant
  • Alcohol consumption
  • Water intake

Women with a higher BMI (body mass index) have a greater risk of developing stretch marks and it is more commonly seen in adolescent women.

It has been suggest maternal age could be a protecting factor against stretch marks experienced during pregnancy and genetics may also contribute to the severity.


The Korean College of Medicine found up to 70 percent of pregnant women experience stretch marks.  Most stretch marks can be seen after 25 weeks of gestation.  It is believed the hormones produced throughout pregnancy which cause the softening of ligaments, also cause the softening of skin fibres.  This increases the risk of the expectant mother developing stretch marks as the baby grows and weight fluctuates.

Medical conditions

Mayo Clinic suggest stretch marks of a strong and more invasive appearance may be caused by an increase of the hormone cortisone.  When the adrenal glands produce excess cortisone, the elastic fibres in the skin are weakened.

A similar hormonal change is seen in Cushing’s syndrome where a faulty gene is responsible for the stress hormone, cortisol to be overproduced.  Again, this results in weakening of the body’s tissues and elasticity.


Research published in the Journal of Investigative Dermatology found that genetics can seriously increase your odds of developing stretch marks.  Mutations in four specific genes (ELN, SRPX, HMCN1 and TMEM18) increased the risk of people developing stretch marks by up to 40 percent.

One gene in particularly was strongly associated with stretch marks, especially those developed during pregnancy.  ELN (known as elastin) is integral to the makeup of elastic fibres in your body.  This helps the tissues stretch and retract while maintaining its integrity.

Preventing stretch marks occurring

Unfortunately there is no solid evidence to suggest coating your pregnant belly or growing breasts with a cream or an oil will prevent stretch marks from appearing.  Consulting professor dermatology at the Duke University School of Medicine in North Caroline suggests “weight gain itself doesn’t cause stretch marks – it promotes the hormonal changes that cause them”.

Simply put, there are some people that are more prone to developing stretch marks then others.  And unfortunately those people are generally women!

To reduce your risk of developing stretch marks, you should:

  • Maintain a healthy weight
  • Avoid regular yo-yo dieting
  • Consume a diet rich in vitamins and minerals especially vitamins A, C, zinc and silicon
  • Keep hydrated
  • Gain weight slowly and gradually during pregnancy

So while applying cocoa butter onto your skin will help with any dryness and relieve itchiness, it’s not going to necessarily stop the unpleasant scars from developing.  If you do treat your stretch marks early you can reduce the appearance of minor marks.  Once they fade and become white, they are fully matured and topical treatments are not going to do much for you.

Improving the appearance of stretch marks

The presence of stretch marks can have a profound impact on your confidence and for many treatment of these unsightly scars is the best option.  But what works?

At Cosmos Clinic we aim to target the collagen fibres in the skin and a multimodal approach is often undertaken. This is due to the treatment of stretch marks begin a challenging process.  Four modalities which have shown significant improvements in the appearance of stretch marks are utilised at our clinic.  These include:

  • PRP (Platelet rich Plasma)
    A procedure where the blood plasma, rich in growth factors, is injected under the skin to stimulate particular stem cells responsible for collagen formation
  • E-Dermastamp / Dermaroller
    A cosmetic treatment which stimulates the production of collagen and new tissue formation through the use of micro-fine needles
  • Fractional Laser
    A procedure which increases the number of collagen and elastin fibres in the targeted area
  • Laser Skin Tightening
    A cosmetic procedure which helps the skin to contract through the heating of collagen fibres.

In this case, there is no one cosmetic treatment considered as the gold standard.  Combining several procedures have shown to be reasonable effective in improving the appearance of stretch marks.

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