Tanning beds expose your skin to more concentrated doses of ageing UVA rays (the rays more likely to cause cancer). In actual fact, the World Health Organization has recommended that no one use tanning beds for cosmetic purposes, listing them as a “known human carcinogen”. For those who don't know, a 'carcinogen' is a cancer-causing substance or agent. Scary stuff.
In addition to increasing the risk of skin cancer, frequent use of sunbeds can also lead to premature skin ageing. I'm talking wrinkles, age spots and a seriously dull complexion.