Because it is effectively a fat burning stack in drink form. Your four big fat burning supple ments are E,C,A and Y. That's Ephedrine, Caffeine, Aspirin and Yohimbine/Yohimbe. In combination, they are usually ECA and ECY. The aspirin is used because ephedrine and caffiene is a strong vasoconstrictor. Aspirin helps to counteract this or in other words, lets you get the benefit of the stims without the heart problems. ECY, however, is rarely recommended anymore because it's simply too potent. The redline drink is a highly concentrated CY drink. Although you don't need to be 18 to buy it (http://www.amazon.com/Redline-Energy.../dp/B0018C2RKK
), it's not recommended for sale to the very overweight because it is actually dangerous unless you understand its contents. If you have any form of heart or neurological condition, it's misleading to simply label it an energy drink because they do not disclose the amount of each ingredient. When you're overweight, you're more likely to have elevated blood pressure as it is. These two stacks are meant for athletes who need to cut a relatively small amount of fat in a shorter period of time, NOT for people who simply want to lose weight. They would not be cardiovascularly fit enough in most cases.
If you're wondering how I know this, yes, I tried many MANY fat loss tricks in my day including the above two. Pop a vasopro ephedrine and a no-doz and go for a swim, and you'll be freaking buzzing. I don't recommend this.