Throughout Europe and Asia, the plant Rhodiola rosea is well-known and used by practitioners of traditional medicine. Its name is becoming more recognized in North America because rhodiola is used to combat the effects of stress and fatigue.
Since rhodiola is believed to stimulate the central nervous system, decrease depression and enhance work performance, researchers at the Ministry of Health in Moscow decided to evaluate its effects on a group of 161 healthy, hard-working cadets, aged 19 to 21. The purpose of this double-blind study was two-fold: to see if rhodiola lived up to its medicinal claims, and to determine the most beneficial dose. The participants were either given a standard dose of rhodiola extract, a 50% higher-than-standard dose of rhodiola, or a placebo. In addition to endurance tests and mental health questionnaires, the cadets were observed for a number of physiological variables including pulse and blood pressure.
After the trial period, researchers found a “pronounced anti-fatigue effect” in the groups taking rhodiola compared to the placebo group. They found no significant difference between the two rhodiola groups, suggesting that there is no benefit to be gained from higher-than-standard dosages of the herb. A typical dose is 50 mg of the standardized extract twice daily.
Sources: Phytomedicine. 2003 Mar;10(2-3):95-105