Rhodiola Rosea Supplements Review
Initial Posting: 3/18/2016
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Summary: What You Need to Know About Rhodiola Rosea Supplements
What It Is:
- Preliminary studies suggest that Rhodiola rosea (R. rosea) may help improve symptoms of depression and anxiety. However, larger and better controlled studies are needed for confirmation. The evidence is even weaker regarding its ability to reduce physical or mental fatigue and improve athletic performance. (See What It Does)
- When choosing a R. rosea product, look for a root extract containing at least 3% rosavins and/or 1% salidrosides — key marker compounds which may also play a role in the herb's activity. (See What It Is)
- Daily dosage of R. rosea extract typically ranges from 170 mg to 680 mg, which may be divided into two doses per day.
- ConsumerLab.com's tests revealed that two products did not contain their listed and/or expected amount of key compounds. (See What CL Found)
- Among the eleven products Approved for quality by ConsumerLab.com, two were chosen as Top Picks.
- R. rosea is generally well tolerated; mild side-effects such as dizziness, headache, nausea and dry mouth have been reported. However, consult your physician before taking R. rosea if you take anti-depressants or supplements for depression, blood-pressure lowering medication or have low blood pressure, or if you have hypoglycemia or diabetes. (See Concerns and Cautions)
Rhodiola (Rhodiola rosea L.) is an herb which grows in Eastern Europe (Siberia), Asia, and in certain coastal or mountainous regions of the U.S. R. rosea is sometimes promoted as the "new ginseng" as it is thought to have similar "adaptogen" qualities, such as modulating the body's response to stress and fatigue and improving mental function. It is also sometimes referred to as "golden root" or "rose root." Since R. rosea is mostly wild-harvested and there is little large-scale cultivation, there is the potential for R. rosea supplements to be adulterated with other species of rhodiola (i.e. R. crenulata, R. heterodonta., R. quadrifida) or cheaper ingredients, in order to fulfill demand. It is also possible that supplements labeled just "Rhodiola" contain these other species.
Compounds called rosavins (e.g. rosin, rosarin, and rosavin) are found in the root of R. rosea and are key marker compounds which can help distinguish R. rosea from other species (Booker, Phytomedicine 2015). The root also contains salidroside, a compound which alone, and in combination with rosavins, may be responsible for some of the herb's antidepressant effects (Panossian, Phytomedicine 2008).
What It Does:
Small, short-term studies suggest several potential uses for R. rosea, but larger, controlled, long-term studies are needed to confirm these findings.
A double-blind, randomized study of an R. rosea extract (containing 340 mg of R. rosea extract (SHR-5) standardized to 3.07% rosavin and 1.95% rhodioloside) in 89 men and women with mild to moderate depression found that doses of 340 mg and 680 mg taken daily for six weeks improved most symptoms of depression, including insomnia and emotional stability, while those treated with placebo experienced no such benefit (Darbinyan, Nord J Psychiatry 2007). At the end of the six weeks, those taking the 640 mg daily dose also had significant increases in measures of self-esteem, while those taking the lower dose, and the placebo did not.
Several years later, using this same type of extract, a well-controlled study was funded by the U.S. National Institutes of Health in 57 people suffering mild to moderate major depression. Modest reductions were observed in depression scores among those taking R. rosea. However, these reductions were only somewhat better than with placebo and not as large as with 50 mg of sertraline (Zoloft) -- and the improvements with either treatment were not statistically significant compared to placebo, partly due to the small sample size. Many more patients reported adverse events using sertraline (63.2%) than with R. rosea (30.0%) or placebo (16.7%). The researchers concluded that although R. rosea had less of an effect than sertraline, it may possess a more favorable risk to benefit ratio (Mao, Phytomedicine 2015). The dose of R. rosea started at 1 capsule daily (containing 340 mg of R. rosea extract (SHR-5). The daily dose of R. rosea, as well as sertraline, was increased every two weeks by one pill in patients not responding to the dose, up to a maximum of 4 pills daily, for 3 months — unfortunately, the study did not report how many people required dosage increases. There were no clinically meaningful differences in changes in systolic and diastolic blood pressure, heart rate, or weight in those taking R. rosea or sertraline.
It's not understood exactly how R. rosea may help to improve symptoms of depression, although some animal research suggests the herb may modify the body's response to stress and interact with certain brain chemicals which can affect mood (Panossian, Pharmaceuticals 2010). One study found that salidroside (also called rhodioloside) and tyrosol (a salidroside metabolite) from R. rosea had the strongest anti-depressant effect in rats, although a fixed preparation containing salidroside, rosavin, rosarin and rosin was "more active than any of the individual components alone, indicating a synergistic effect." (Panossian, Phytomedicine 2008). Additionally, some in-vitro studies suggest R. rosea may inhibit monoamino oxidase (MAO) activity (van Diermen; Planta Med 2008; van Diermen J Ethnopharmacol 2009) in the way that MAO inhibitor drugs for depression do; however, no effect on monoamino oxidase (MAO) activity was found when
R. rosea extract was given orally in an animal study (Mannucci, Phytomedicine 2012) and there do not appear to be any studies of
R. rosea's effect on MAO activity in people.
Very preliminary studies suggest potential benefit of R. rosea for treating anxiety. One such study in a small number of young adults with mild anxiety found that those who took a tablet containing 200 mg of a proprietary R. rosea extract known as Rosavin (or WS 1375 -- chemical composition not disclosed) from the product Vitano (from Dr Willmar Schwabe GmbH & Co. KG) 30 minutes before breakfast and 30 minutes before lunch (for a total daily dose of 400 mg) for two weeks, reported significantly lower levels of anxiety and improved mood compared to those who did not take the extract (Cropley Phytother Res 2015). However, this study did not include a placebo, and measures of anxiety were self-reported.
An open-label study in ten men and women diagnosed with generalized anxiety disorder (GAD) found those who took one tablet containing 170 mg of a R. rosea extract (Rhodax, Phoenix Laboratories by Bodyonics Ltd.) (standardized to contain a total of 30 mg of rosavins, salidroside, and other compounds -- rhodalgin, acetylrhodalgin, rosaridin, and rosaridol) in the morning and again in the evening (for a total daily dose of 340 mg extract) had significant decreases in measures of anxiety. Five of the ten participants had a decrease of 50% or more in anxiety scores and, of these, four met the criteria for remission of anxiety (Bystritsky J Altern Complement Med 2008). However, due to the small size, lack of a control group, and lack of blinding, no real conclusions can be drawn from this study.
Physical and Mental Fatigue
Although a few preliminary studies have reported a potential benefit for physical and mental fatigue, the small size of the studies and mixed results do not seem to support R. rosea for these uses. Examples include the following:
A study among 56 healthy young physicians performing night duty work found that one tablet containing 170 mg of R. rosea extract (SHR-5, described above), including 4.5 mg of salidroside taken once daily for two weeks significantly improved mental fatigue (as measured by cognitive testing of short-term memory, calculation and ability to concentrate, etc.) after night shifts compared to placebo. No adverse effects were reported (Darbinyan, Phytomedicine 2000). However, as noted in a review of clinical trials, the fatigue index used in this study does not appear to be validated, and combined with a lack of certain other data, it is difficult to draw conclusions from this study (Ishaque, BMC Complement Altern Med 2012).
A study using 50 mg of same extract daily given twice daily to students (ages 17 — 19) during a period of school exams (20 days) improved a measure of hand-eye coordination (maze test) by 50% and decreased self-reported scores of mental fatigue compared to placebo (Spasov, Phytomedicine 2000). Those taking the extract also had less of an increase in heart rate during a physical fitness test compared to placebo. However, other measures of motor and cognitive performance, such as motor speed (finger tapping test) and a test of mental work capacity (correcting written text), were not improved compared to placebo.
Interestingly, a study among 40 nursing students (ages 18 — 55) who took R. rosea root powdered extract standardized to 2.8% rosavins (the students chose based on their fatigue levels each day whether to take 2 or 3 capsules, providing a total daily dose of either 364 mg or 546 mg of extract daily) or placebo, upon waking, daily for 42 days found that physical and mental fatigue worsened in those taking the extract compared to placebo (Punja, PLoS One 2014). The researchers theorized that the small size of the study may have affected the results, and proposed that a higher dose might show an effect, but this is speculative. Adverse events, including headache, nausea and diarrhea were similar to placebo and were mild to moderate — although two adverse events, dark stool and blurred vision, were reported (by one participant each) only in the group taking R. rosea.
Overall, a review of ten randomized controlled studies on the effects of R. rosea on physical and/or mental fatigue concluded that due to contradictory findings and design flaws in some studies, there is currently insufficient evidence to determine whether there is a benefit (Ishaque, BMC Complement Altern Med 2012).
Although R. rosea is sometimes promoted for improving exercise performance or endurance — perhaps due to its potential to reduce fatigue - the evidence weak. Most studies available to date involve an extremely small number of subjects and have reported only small benefits, if any, compared to placebo.
One small study, for example, reported that a single, 200 mg dose of R. rosea extract (containing 3% rosavin and 1% salidroside) slightly increased the time to exhaustion (a measure of physical endurance) -- from 16.8 to 17.2 minutes -- during a physical function test, but did not increase muscle strength or reaction time, compared to placebo; additionally, when a small subset of the participants took the same dose of the extract daily for four weeks, there was no improvement in any measures of physical performance (De Bock, Int J Sport Nutr Metab 2004).
Other small studies have reported slight improvements in ratings of perceived exertion (RPE) using R. rosea providing 3% rosavin and 1% salidroside (Bulknutrition.com) taken with water one hour prior to exercise at a dose of 3 mg per kg of bodyweight, or about 204 mg for a 150 lb. person. One of these studies was in 18 women in which the rhodiola appeared to decrease RPE during a bicycle test compared to placebo (Noreen, J Strength Cond Res 2013). A similar study in ten men showed a modest decrease in RPE and significantly increased self-reported scores of "pleasure" and "vigor," but no effect on heart rate or energy expenditure, compared to placebo (Duncan, J Sports Med 2014).
A study in twelve resistance-trained men who took 1,500 mg of R. rosea (standardized to 3% rosavins) per day for 4 days before a session of resistance exercise found no improvement in RPE or measures of muscle recovery compared to placebo (Walker, Metabolism 2007).
Quality Concerns and What CL Tested for:
There are concerns about rhodiola supplements not containing what they claim, including a study which found that nearly 20% of rhodiola products in the UK did not contain rosavin, the key marker compound and many others appeared to be adulterated with other Rhodiola species. However, in the U.S., neither the Food and Drug Administration (FDA) nor any other federal or state agency routinely tests supplements for quality prior to sale. In order to help consumers identify products of better quality, ConsumerLab.com purchased and tested R. rosea supplements to determine whether they contained the labeled and expected amounts of rosavin compounds (referred to collectively in this report as total rosavins) and salidroside, and, if a root powder (as opposed to an extract), did not exceed contamination limits for lead, cadmium and arsenic.
See How Products Were Evaluated for more information on testing.