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O Gizmo Test: The No!No! and The Marvel-Mini
The last time our executive beauty editor, Jenny Bailly, tried to give herself a treatment—beyond the basic cleansing, sloughing, filing—at home, things didn't end well. (How tough could it be to give yourself a bikini wax? Very.) Since then, she's left the hard (and hot) stuff to the pros. But two new, intriguing little gadgets caught her eye recently, so she gave them a shot.

1. The No!No!
What it is: A rectangular device, smaller than a cell phone, that's billed as "a professional treatment for hair density reduction."
How it works: As you slowly roll it along your leg, the pressure activates the No!No! and warms it up. "The heat kills the cells of the hair follicle," explains Francesca Fusco, MD, assistant clinical professor of dermatology at Mount Sinai School of Medicine.
How it feels: You can definitely feel the heat, but it's comfortable. (The smell of burning hair, on the other hand, can be slightly disconcerting.) Afterward, Jenny's skin was a little tingly, as if she had a slight sunburn, for an hour or so.
Why it might be worth trying: A study published in the Journal of Drugs in Dermatology found that women who used the device twice a week for six weeks had a 64 percent reduction in hair six weeks after treatment. After 12 weeks, they still had 43 percent less hair. "That's about comparable to what you see with laser hair removal," says Fusco. "And since this treatment is heat, not light, based, it's safe for all skin colors."
Why it might not: Treating both legs takes about 30 minutes (and you have to do it twice a week to see results). The reduction isn't permanent—if you stop using the No!No!, the hair will slowly return.
What it costs: $250.

2. The Marvel-Mini

What it is: A device, about the size and shape of a hairbrush, that uses LEDs (light-emitting diodes) to reduce wrinkles, acne, and hyperpigmentation.
How it works: You hold the light panel to a portion of your face; after three minutes, the machine beeps to tell you that it's time to shift it to another area. The company recommends using it twice a week, for 24 minutes total each time.
How it feels: Like nothing. Jenny had slight discomfort in her arm from holding the device up, though.
Why we thought it might be worth trying: Studies have shown that professional LED treatments (the most common brand names are GentleWaves and Ominlux) stimulate skin cells to produce new collagen and even out skin tone. "After five or six treatments with Omnilux, a patient's skin looks more luminous and less tired," says David J. Goldberg, MD, director of laser research in the department of dermatology at Mount Sinai School of Medicine.
Why we decided it wasn't worth the money: There is no clinical evidence that the Marvel-Mini compares to a pro treatment. Jenny counted 37 diodes (or bulbs) in Marvel-Mini; the LED machines in Goldberg's office contain "hundreds."
What it costs: $225.