Get Involved
About Us
Our Members
Small Pilot Study Finds Rhodiola Extract May Be Beneficial for General Anxiety Disorder
Reviewed: Bystritsky A, Kerwin L, Feusner JD. A pilot study of Rhodiola rosea (Rhodax®) for generalized anxiety disorder (GAD). J Altern Complement Med. 2008; 14(2):175-180.

Rhodiola (Rhodiola rosea, Crassulaceae) is a plant that is traditionally consumed as a tea. Rhodiola root is considered an adaptogen—an herb that purportedly conveys resistance to multiple kinds of stressors as well as enhances adaptation to stress.1 More than 100 scientific and clinical articles on rhodiola root preparations have been published and many report improvements in stress, fatigue, and irritability. Considering that these symptoms are often associated with generalized anxiety disorder (GAD), the authors conducted a preliminary study to assess the effect of rhodiola on GAD.

Ten outpatients (mean age: 44 years) living in Los Angeles, with a current diagnosis of GAD (≥ 16 on the Hamilton Anxiety Rating Scale [HARS] and < 17 on the 21-item Hamilton Depression Rating Scale [HDRS]), participated in this 10-week open-label study. Patients on stable pharmaceutical medication with residual GAD symptoms could continue on the medication. Patients took 170 mg standardized rhodiola root extract as a tablet (Rhodax,® Phoenix Laboratories, Bodyonics Ltd., Farmingdale, NY*) twice daily for 10 weeks. Psychological assessments included the HARS, HDRS, Clinical Global Impressions of Improvement (CGI-I), and Four Dimensional Anxiety and Depression Scale (FDADS).

Compared with baseline, at 10 weeks there was a significant decrease in HARS (P = 0.001), HDRS (P = 0.001), and FDADS anxiety subscale scores (P = 0.043). At endpoint, 50% (5/10) of the patients had at least a 50% decrease on the HARS and were considered to be responders to treatment. Four of 10 subjects (40%) met the criteria for having reached remission. Two patients were considered to have “minimally improved” according to the CGI-I. Adverse events (AEs) were mild to moderate. The most common were dry mouth (4/10) and dizziness (2/10). No patient discontinued participation due to AEs.

This is the first report that rhodiola exerts anxiolytic effects. The authors compared rhodiola’s effect size with the effect size reported in placebo-controlled studies on conventional pharmaceutical drugs to get a crude estimate of whether rhodiola’s effects were due to a placebo effect. They concluded that the anxiolytic effect could not be assured on the basis of data from this study.

The primary value of this study is that it may suggest a new potential area for further research and potential clinical use for rhodiola preparations. However, no clinical recommendations can be made on the basis of this small, uncontrolled pilot trial as it is severely limited by numerous factors: the small sample size, the open-label (unblinded) design, and the fixed dosing schedule. The fixed dosing schedule is a potential drawback because pharmaceuticals to treat anxiety are normally dosed in practice and in clinical trials as a daily dose that is adjusted upward or downward by each physician or site investigator based on what dose is deemed clinically indicated. Thus, it is possible that in this trial that more patients might have experienced an improvement if the dose had been adjusted to meet specific conditions. In sum, this rhodiola preparation should be tested for a potential anti-GAD effect in a randomized, placebo-controlled, double-blind study with more patients to provide sufficient statistical power.

—Heather S. Oliff, PhD


1. Panoissan A, Wikman G, Wagner H. Plant adaptogens: earlier and more recent aspects and concepts on their mode of action. Phytomed. 1999;6(4):287–300.

*Rhodax rhodiola root extract is standardized to contain 30 mg of “all 8 essential biomers”: rosavin, rosarin, salidrosides, rosin, rhodalgin, acetylrhodalgin, rosaridin and rosaridol, according to the www. Web site [accessed Aug. 23, 2008].