Stretch marks are long, thin streaks that occur on the surface of the skin. They’re often red or purple to start with, before fading to a silvery-white colour. They’re particularly common during pregnancy, puberty or following rapid weight gain. They’re more common in women but can also affect men.
Causes of stretch marks
Stretch marks are caused when the skin rapidly stretches as a result of sudden growth or weight gain. This causes the middle layer of skin (dermis) to tear, allowing the deeper skin layers to show through, forming stretch marks.
The dermis contains fibres that allow your skin to stretch as your body grows. Rapid growth can cause the skin to over-stretch and break the fibres. The tears in the dermis allow the blood vessels below to show through, which is why stretch marks are often red or purple when they first appear.
When the blood vessels eventually contract (get smaller), the pale-coloured fat underneath your skin will be visible, and your stretch marks will change to a silvery-white colour.
Where stretch marks occur
Stretch marks can occur anywhere where the skin has been stretched.
They usually affect areas where fat is stored, such as:
- tummy (abdomen)
- upper arms
- shoulders (in bodybuilders)
Sometimes stretch marks can develop on the back, overlying the spine horizontally, particularly in teenage boys.
When stretch marks occur
Stretch marks often occur:
- during pregnancy
- after rapid weight gain
- during puberty
- if you have a family history of stretch marks
- if you have an underlying health condition, such as Cushing's syndrome or Marfan syndrome
- after long or inappropriate use of corticosteroid medication
Most stretch marks aren't particularly noticeable and will fade over time. If you have unsightly stretch marks, or if they affect a large area of your body, there are treatment options available. However, there is little evidence to show that these treatments work.
Preventing stretch marks
Stretch marks can't always be prevented – for example, they often occur during pregnancy. However, there are some things you can do to help lower your chances of getting stretch marks.
Weight and diet
Stretch marks are often caused by gaining weight rapidly over a short period of time. Avoiding rapid weight gain and weight loss can help prevent stretch marks.
If you need to lose weight, you should do it slowly by:
It's important to eat a healthy, balanced diet that's rich in vitamins and minerals, particularly:
These vitamins and minerals will help keep your skin healthy.
Body mass index (BMI) is a measure most people can use to check whether their weight is healthy in relation to their height and build. For most adults, a BMI of 18.5 to 25 is considered healthy.
- Use the BMI healthy weight calculator to find out whether you're overweight.
Stretch marks during pregnancy are usually caused by hormonal changes that affect your skin. Gaining pregnancy weight steadily may help minimise the effect of stretch marks.
During pregnancy, it's normal to put on weight over a relatively short period of time. However, you don’t need to "eat for two", even if you're expecting twins or triplets.
If you're pregnant you don't need to go on a special diet, but you should eat a variety of foods every day to get the right balance of nutrients for you and your baby.
Emotional effects of stretch marks
Some people find having stretch marks distressing. See your GP if you have stretch marks and you're depressed, or they're affecting your daily activities.
There are a number of organisations which may be useful sources of help and support, including:
More useful links
The information on this page has been adapted from original content from the NHS website.
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