Yes, they can! We do it ourselves (and use them ourselves) and that is also the main reason we recommend our mixes. We always combine herbs that support each other and multiply their effect. For example, Guarana + Maca, Tribulus + Maca, Guarana + Ginseng, etc. All of our mixes are created to a 50/50 ratio (50% guarana, 50% maca, etc.), and are a great way to get more nutrition on the go!