If the valves inside your blood vessels become weak (whether from age or genetic predisposition) and are unable to pump blood back to your heart efficiently, “the blood pools and causes the veins to enlarge,” says Robert J. Min, chair of radiology at Weill Cornell Medical College, in New York City. That causes capillaries close to the skin’s surface to show up as little red squiggles, most commonly on the legs. And those, friends, are spider veins.

What Works

Sclerotherapy: Using a tiny needle, a doctor injects the spider veins with a medicated solution that “causes them to collapse and permanently disappear,” says Fredric Brandt, a dermatologist in Miami and New York. You’ll probably need two to three sessions to eradicate a spider vein fully.
Cost: $200 and up per treatment.

Vascular Laser: “The blood inside the veins absorbs the wavelength from this laser, creating heat, which contracts the veins,” says Richard G. Glogau, a clinical professor of dermatology at the University of California, San Francisco. Very small spider veins benefit most; you’ll need several sessions to see a difference.
Cost: $200 and up per treatment.

What Doesn’t Work

Keeping your legs uncrossed (crossing them is said to cause spider veins). “Unless they’re crossed 24 hours a day, the effect is minimal,” says David Goldberg, a dermatologist with practices in New York, New Jersey, and Florida.

Quick Cover-Up

Neutralize redness with yellow-based body makeup, says Lusine, a makeup artist in Los Angeles. Set with translucent powder to keep it in place (and off your clothes).