What is the underlying cause or causes of stretch marks?

Answer 1

Causes

When the skin is stretched, such as during weight gain or during pregnancy, the stretching breaks or permanently damages the underlying skin fibers and skin cells. This has nothing to do with dry or dead skin-- it is simply that stretching, even of supple (soft, pliable) skin makes it weaker.

As a comparison, if I took a rubber band (called "gum band" in some regions) and looked at its surface in a non-stretched state, the surface would appear soft and smooth. However, if I stretched the rubber band between two points, pulling it further and further apart, the surface would begin to appear a bit rough and thinner. Some sections of the rubber band would still seem "normal" but the imperfections would be worse at places where the band was the weakest. If examined with a strong light, you might even see "through" the band easier than in other places on the band.

The lower abdomen, the female breasts, our buttocks (butt)/the anus, our thighs, and our arms -- these areas in particular -- have layers of muscle and fat beneath the skin. As the skin is stretched, these layers also s-t-r-e-t-c-h, with some places being weaker than in other places. As more stretching force or forces of body weight "pull" on the connective tissue beneath the skin and between the muscle-fat-skin layers, those weakest places become thinner and thinner until the skin becomes almost see-through (translucent). It may become so thin in places that we can see a bluish tint under the skin-- the blue tint shows wherever surface capillaries are close to the outer skin and where the tissue has become so stretched that we see the blood within the capillaries.

Despite what some people think, dry skin does not cause or make stretch marks, nor does dry skin make it worse. Conversely, hydrated skin--from the inside out--is more pliable. But even hydrated skin can develop stretch marks because it is the underlying connective tissue that is damaged in stretch marks. In fact, the actual stretch mark usually feels silky and softer than undamaged skin-- again, because the skin's underlying strength has been "broken" by the forces stretching it.

If stretch marks were caused only by dry skin, as some people believe, that would mean every pregnant female or overweight person could prevent stretch marks simply by drinking more fluids and by liberally lathering their bodies with oily moisturizing lotions or creams. if true, that would also mean that drinking more fluids or lathering the body with lotions would reverse stretch marks, or "cure" them and make them "heal" and go away. But neither of these remedies prevent or cure stretch marks. But companies who manufacture "stretch mark creams" have made a fortune on such products simply because stretch marks are considered unsightly flaws. But stretch marks are very common, from the young to elderly, as the body undergoes forces from gravity, aging, child-bearing, and weight gain. Very few humans can honestly say they don't have even one stretch mark--somewhere, even if only around the anus/buttocks.

Prevention

Since forces and weight gain can contribute to the development of stretch marks, prevention must center on the aspects involved in gravity, aging, child-bearing, and weight gain that we can control. We can't stop gravity or aging. Reproduction is for many people a human drive and need, so while we can control reproducing, we can't fully stop the "stretching" forces involved in pregnancy. Of these 4 forces, the only one we can fully control is weight gain.

Women intending to become pregnant or who are in the first trimester can do exercises to keep the lower abdominal muscles strong and reduce the effect of stretching forces on underlying tissues. Fat has less support for muscles and skin, so a lean muscular body will be less prone to stretch marks than a fatty pre-pregnant body.

Fluids and lotions

Fluids can keep the skin more supple and healthy, as it does for all of the body. But even well-hydrated persons can get stretch marks.

If lotions help the tingling or itchiness that is common to having stretched skin, they can do no harm. But women, especially, should understand that no lotion can penetrate the skin to heal or cure weak or broken areas of connective tissue. Once a stretch mark has appeared, you'll likely have it for life.

Answer 2

Stretchmarks are usually caused when the boobs grow too fast, or if the person is overweight.