Hi everyone! I have been lurking on this site for awhile and jumped on the MN bandwagon a week ago. i must say, I'm pretty impressed so far! I can barely comb thru my roots, lol! I believe what makes it work is the nitrate in the formula. I'm a nurse and we use nitrate patches on the chest, or pills for people with chest pain/angina. Nitrates are vasodilators ( makes the arteries dialte) which increases blood flow to the heart, so by applying to the scalp, we are increasing the blood flow to the hair follicles, which causes increased growth! Also, a side effect of nitrate usage is headache, which is why we give patients tylenol after the patches. HTH!