Intense Pulsed Light is relatively new. The interesting thing about it - providing it's put in the right hands - is that it is much less invasive than a peel. And there is no downtime.
A computer-regulated light pulse heats a portion of the skin. This removes the unwanted tissue while it spares or avoids the surrounding healthy or "normal" tissue. This is because both long and short wavelengths of light can be delivered allowing better targeting than a traditional laser. By the same token, the penetration depth and degree of heat needs to be highly controlled to minimize complications.
Particularly effective when aimed at blood vessels, age spots, freckles, flat pigmented birthmarks, and other types of discolorations. It is one of the few procedures that effectively treats rosacea. An additional bonus is that the treatment causes inflammation of tiny blood vessels in the skin which stimulates the production of new collagen.
When locating a practioner it seems to be worth checking which machine they are using. Lumenis makes the machines of choice - being most powerful and having the widest range of settings - named PhotoDerm and EpiLight. More recent machines have more limited settings and less power to prevent less experienced, and non-physician operators from producing undesirable side effects. Quantum (Aculight) and Vasculight are Lumenis low-setting products.
A friend who has tried this just once said that IPL really does even out skin tone. In her experience, dark spots got darker before they disappeared. It's easy to overdo it - even, in this case, in the hands of a trusted practioner. "I wasn't burned," she said, "but a patch of skin went really dark."
There isn't much hard core research in this area. I did find one study, conducted in Oregon, that found that the five patients who tried it reported about a two year reduction in percieved age after several IPL sessions. Another claims that IPL patients reported a reduction in cellulite.
I've been noticing that a lot of dermatological studies rely on patient self-reporting. This is frustrating for those of us that want some hard empirical evidence. I know that perception is nine-tenths of reality, but who amongst us wouldn't look in the mirror after undergoing this stuff and REALLY WANT to believe that it worked.