Yerba mate can actually boost your energy, because it has caffeine in it. Yerba mate has naturally occurring caffeine in it, much like coffee. But, what is useful for some people is that a lot of people feel some anxiety with coffee that they don't notice with even black tea, cream tea, or even yerba mate. So if you find that coffee makes you too anxious, try caffeine from another source like tea or yerba mate instead. The key concern with yerba mate is that if you consume high amounts of it, there is a likelihood that you could encounter some cancers. Yerba mate is closely linked with a couple of different kinds of cancer for people who drink it in high amounts regularly. So you might want to stick with things like green tea or black tea that are not associated with cancer risk. If you like the taste of yerba mate you could get some of the benefits from it by mixing it with another tea, like green tea or black tea, but again you want to make sure that you're not drinking too much of it. Now, the studies that show that yerba mate is linked with cancer, are people who were drinking it for decades and drinking many many cups of it a day, like more than five cups a day. So if you're having one a day or one a day every few days, then maybe yerba mate is safe for you. But be aware, that it is linked with certain types of cancers.