If I understand your question and your motives, You are wondering about the safety of rubbing something similar to nitroglycerine into your scalp? Well Chemically, yes, these two chemicals are similar, as Nitroglycerine is just an extension to the Glycerin (Glycerol) molecule. http://en.wikipedia.org/wiki/Image:Nitroglycerin-2D-skeletal.png http://en.wikipedia.org/wiki/Image:Glycerine_chemical_structure.png If you look at those, you can see that the H's on the Glycerol Molecule are replaced by Nitrite molecules; attaching to the O atoms of the glycerol molecule. This happens through "Nitrification", or treating Glycerol with very concentrated Sulfuric and Nitric Acids mixed together. The strong acids pretty much force some extra bits onto the Glycerol molecules (extra bits meaning N and O atoms together in a Nitrite form). In chemistry, changes like this to structure of molecules have huge effects on the real world properties of a substance. Nitroglycerine and Glycerine are good examples. Glycerine is a type of sugar believe it or not. You can buy it in a chemist or supermarket, and its a thick syrupy clear liquid: it tastes *unbelievably sweet*, it really is amazing how sweet something can be. Other than this, its a pretty inert and unexciting substance. Basically just a very strong and liquid form of Sugar. Nitroglycerine however is a yellow oily substance: friction sensitive and explosive. I believe it also tastes and smells a bit sweet, but I'm not sure. It dilates blood vessels when taken medicinally too: its used to treat angina and a few other circulatory and cardiac problems. As a substance, those extra Nitrite Molecules make a big difference: the two substances have totally different effects on the human body, and they behave completely differently physically. Hope that helps! Feel free to ask some extra questions, Ill try to help as best I can. If anyone wants to jump in correct any of my slightly dodgy chemistry, feel free.

If you take glycerin which is basically a chain of 3 carbon atoms and you add nitrate to each you get nitroglycerin. If you take glycerin (and you do constantly) and add long chain fatty acids you get ..... fat. Olive oil is a monoglyceride which is one fatty acid on glycerin. Chemistry is fun!