Cinnulin PF is an extract from Cinnamomum burmannii. The proprietary extraction process helps filter out toxins found in whole cinnamon. It can be used as a general health supplement, but specifically help with blood sugar and your immune system. However being that I am mainly interested in bodybuilding applications, Cinnulin PF has been shown to be beneficial in conjunction with creatine monohydrate.
I found this study that shows participants that took creatine and Cinnulin PF had better results when lifting.
You have to be careful when you buy Cinnulin PF as there are many bogus one out there. The one that I recommend is from Swanson