Studies are still being done, but there are two main theories that are accepted by scientists.
➀ Physical Factor / ➁ Hormonal Factor
➀ Over-stretching of the skin past its threshold elasticity level
The human skin is made up of three layers: the epidermis, the dermis, and the hypodermis.
The middle layer dermis, is rich in elastin and collagen, which play a major role in keeping the skin tight.
In any period of rapid expansion of the body, elastin and collagen production isn’t always able to keep up with the stretching of skin.
This disruption in the dermis layer causes elastin to lose elasticity and eventually tear, resulting in discolored scarring of the skin, the stretch mark.
➁ Secretion of the hormone glucocorticoid
The human body secretes high level of [simple_tooltip content=’A type of hormone produced by the adrenal glands’]glucocorticoid[/simple_tooltip] during periods of puberty, pregnancy in women, bodybuilding, and obesity.
When glucocorticoid level rise in the bloodstream,
it disrupts the formation of collagen and elastin fibers in the dermis,
decreasing its elasticity, and again eventually resulting in a stretch mark.
✪Another lesser known risk factor of stretch marks is Cushing’s syndrome.
Stretch marks are indicative of this syndrome because it causes the body to produce a higher amount of cortisol.
Cushing’s syndrome causes weight gain and thinning of the skin, leading to the formation of reddish-purple stretch marks.