This seems to be a good replacement for the Guarana tea I am currently consuming.

Maté contains xanthines, which are alkaloids in the same family as caffeine, theophylline, and theobromine, well-known stimulants also found in coffee and chocolate. Maté also contains elements such as potassium, magnesium and manganese. Caffeine content varies between 0.3% and 1.7% of dry weight (compare this to 2.5–4.5% for tea leaves, and 1.5% for ground coffee).