A 2015 randomised controlled trial involving 81 university students investigated the effects of the herb Rhodiola rosea on mild anxiety and stress. The active group of 40 students were given Rhodiola twice daily for 2 weeks, the 41 students in the control group received no intervention.
The self-reporting tools used by the students during the trial were the Speilberger State-Trait Anxiety Inventory (STAI) and a perceived stress scale.
Treatment with Rhodiola demonstrated a significant reduction in anxiety and stress when compared to the control group after 14 days. The treatment group also reported a reduction in anger, confusion and depression compared to the control group.