Within the family of nut based oils - pistachio oil is considered a medium weight oil in its molecular structure. With that said, it's slightly heavier than pecan oil, but not quite as heavy as extra virgin olive oil would be. This means, that when you apply pistachio oil to your skin, a percentage will sink in, and a percentage will stay on the surface layers of the skin.
Within the family of nut based oils, pistachio oil is considered a "medium weight oil" in its molecular structure. What that means, is its slightly "heavier" than oils like pecan, but not quite as heavy as macadamia nut oil. The benefits to using a medium weight oil generally deals with absorption thru the skin layers. When you apply pistachio oil to your skin, a percentage will sink in, and a percentage will stay on the surface layers. This quality makes it an excellent blending oil depending upon what formulation you are creating. For instance, if you are designing a nigh time cold cream, I would certainly recommend this oil to be blended into your formulation. Also works great in body scrubs, healing salves, blooming bath oils and let's not forget cold process soaps.
And if that doesn't sell you on trying this oil -- there is a very interesting read by the US National Library of Medicine that can be found online. After much research, they are linking internal usage of pistachio oil to anti-inflammatory benefits. Generally what works on the inside, works on the outside in a similar nature, so its very possible that this oil would make an excellent candidate for any product designed to soothe inflamed, irritated skin.