Hair loss is one of the most despised side effects of chemotherapy, and now breast cancer patients are getting a new way to save their locks.

The Food and Drug Administration said Tuesday it would allow marketing of the DigniCap to chill patients' scalps - using a cap connected to a cooling machine - as they receive chemo. A study found it significantly reduced hair loss.

The near-freezing temperature is supposed to reduce blood flow in the scalp, making it harder for cancer-fighting drugs to reach and harm hair follicles.

It's an idea that's been around for decades, and several versions of cold caps are sold around the world. But the DigniCap, made by Sweden's Dignitana AB, is the first to pass FDA scrutiny.