People ask me all the time what supplements I take and do they really work. It's no wonder that people question the integrity of supplement companies these days with the large amount of marketing dollars, fancy product packaging, and claims that you'll receive massive changes by taking these products. The competitive marketplace for supplements is a billion dollar industry and each new product has to be different or better than what currently exists to be able to sell. Whenever you look at these products it's important to look at what ingredients are in it and do your research on those. Most products breakdown to a handful of main raw ingredients that do the majority the effects that you'll feel. It's important to keep in mind that each persons body is different and each person will react differently to different products. Myself i know that my body reacts very well to creatine based products as well as caffeine. On the other hand, pre-workout N.O. based products (Most use Arginine) don't work so well for me. The best advice that I can give you is to ask for product samples at your local nutrition store if you don't know if the main ingredients work for you. Company websites also will have areas that you can signup to have samples shipped to you free of charge.