Stretch marks are a normal part of puberty for most girls and guys. When a person grows or gains weight really quickly (like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up the connective tissue in your skin) is disrupted. As a result, scars called stretch marks may form.

If you're noticing stretch marks on your body, you're not alone. Most girls and women have stretch marks, which tend to show up on the breasts, thighs, hips, and butt. Many women get them during pregnancy. And while they're more common in girls, guys can get stretch marks, too.

People who are obese often have stretch marks. Bodybuilders are prone to getting stretch marks because of the rapid body changes that bodybuilding can produce. Stretch marks also may occur if a person uses steroid-containing skin creams or ointments (such as hydrocortisone) for more than a few weeks, or has to take high doses of oral corticosteroids for months or longer.

At first, stretch marks may show up as reddish or purplish lines that may appear indented and have a different texture from the surrounding skin. Fortunately, stretch marks often turn lighter and almost disappear over time. But the fact that stretch marks usually fade and become less noticeable over time can be little consolation if you plan to spend most of your summer in a bathing suit.

Here are some things to consider if you want to make stretch marks less noticeable:

• Some people find that sunless tanning treatments (both over-the-counter lotions and sprays and in-salon types of treatments) can help cover up stretch marks. This doesn't work for regular tanning or tanning beds, though, because stretch marks themselves are less likely to tan. And as everyone knows, the sun and tanning beds do more harm than good when it comes to the long-term health of your skin. You also can buy body makeup matched to the tone of your skin that can make stretch marks all but invisible. Although some manufacturers make these cover-up products water-resistant, makeup may not be the best solution if you'll be spending a lot of time in the water.
• Speaking of pool or beach time, the good news is that current fashion favors many styles of bathing suits that also just happen to hide stretch marks. "Boy short" style suits (popular with many athletes because they don't ride up when a person moves) work well for hiding stretch marks on the buttocks and upper thighs. And because many swimmers prefer high-neck bathing suits, which can hide stretch marks in the chest area, there are usually lots of styles to choose from.
• Although there are tons of creams and other skin products on the market that claim to eliminate stretch marks, the truth is that most are ineffective and often costly. You can't make stretch marks go away entirely without the help of a dermatologist (a doctor who specializes in treating skin problems) or plastic surgeon. These doctors may use one of many types of treatments - from actual surgery to techniques such as microdermabrasion and laser treatment - that reduce the appearance of stretch marks. These techniques are expensive and are not usually recommended for people in their teen years because they are not finished growing and their stretch marks will probably diminish over time anyway.