Nutrilite Double X is hands down the best supplement you will find on the market. Double X is made by Nutrilite, which is the company who first marketed the multi-vitamin in North America. First of all, there is probably not a person in this country that would not benefit from a multi-vitamin, as there is no way we could possibly get all the vitamins, minerals, and nutrients we need from our diets alone. It definitely costs more than the multi-vitamin you would find in the drug store, but it is because you are paying for quality and it is worth every penny. You must take three different supplements because they could not pack all the vitamins, minerals, and phytonutrients all into one supplement. I have been taking Double X for years, and my hair and neails seem to grow at an abnormal fast speed. I also noticed a pretty quick change in my energy levels with Double X. Even today, if I forget to take a couple, I notice a difference in my energy levels. Be sure to take your Double X with a meal though; because of the strength of everything packed into it, you definitely will not want to take it on an empty stomach.