What is difference between the fraxel facial laser treatment and the gentle yag facial laser treatment?

The answer is not so simple, as Fraxel can be in many different wavelengths. This treatment can be 'adjusted' with the power and passes. Fraxel 1927 is the gentlest of all Fraxels, and downtime is only 5-7 days. This is a Fractional Laser- namely it treats a certain percentage of your skin. This is ideal for pigmentation and improvement of skin texture. If performed correctly, one treatment will yield outstanding results. Now, gentle ND Yag is also called ' skin toning' this laser is non ablative- meaning your downtime should be ZERO, only mild redness after the laser treatment is the end point. The flip side? You will require 8-10 treatments. Nd Yag works by 1. Treatment of pigment 2. Skin toning- gentle collagen stimulation given the deep penetration of the laser (1064 wavelength). Both treatments have their use, the most important aspect is WHO performs the treatments? The choice is yoursCheersDr Davin Lim Laser dermatologistwestderm.com.au Brisbane, Australia. 

I'm not sure what you are trying to treat, but these treatments are very different. A Gentle Yag laser is just that - a YAG laser. It tends to treat reds in the skin and skin discolorations. A Fraxel is not actually a laser. It is a fractionated energy source that removes some areas of skin that then allows new collagen to be produced in these areas, allowing for a resurfacing. They are not similar, they are not the same, and really, a lot of times we use both to treat the same person since they are used for very different things. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."