Tanning treatment consists of both over-the-counter lotions & sprays and in-salon types of treatments. Some people find that sunless tanning 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. Additionally as is common knowledge now that the sun and tanning beds do more harm than good when it comes to the long-term health of your skin.

Because of their silvery color, most people have the misconception that they can cover up stretch marks with a tan. This however, will only serve to worsen the whitish appearance of stretch marks as the surrounding healthy skin darkens in color. This is because stretch marks are scars and if you've ever tried to tan a scar, you would know that they are particularly resistant to color changes.

Tanning may diminish but never eliminate stretch marks. You should be sure to use sun screen. There are, however, many ways to make stretch marks less noticeable. Sunless tanning treatments help to cover up stretch marks. Outdoor tanning or tanning beds do not work to diminish the appearance of stretch marks because stretch marks do not tan as well as undamaged skin.

Tanning would probably make them more apparent. The skin that was stretched is a different texture (stretched skin) and color (sometimes lighter or darker), and so tanning will only accentuate the different skin tones and it would be hard to make the color even, unless you used makeup.