Rhodiola is a traditional medicine and supplement that is used for a wide range of complaints including amenorrhea, depression, insomnia, fatigue, cancer, headaches, schizophrenia, colds and flu, hypertension, and male sexual dysfunction.
There is a specific interest in the use of Rhodiola for asthenia. I just love this term.
Asthenia refers to a decline in work performance, sleep disturbances, poor appetite, irritability, hypertension, headaches, and fatigue. Sound like anyone you know?
Let’s see if Rhodiola is as good as it says on the box.
What Is Rhodiola Rosea?
Rhodiola (Rhodiola rosea) is also called Arctic root, roseroot or golden root, and belongs to the Crassulaceae family of plants. It grows well at high altitudes in the Arctic and in mountainous regions throughout Europe and Asia.
Over 200 different species of Rhodiola have been identified and classified. At least 20 species of Rhodiola are used in traditional medical systems in Asia. These include R. rosea, R. alterna, R. brevipetiolata, R. crenulata, R. kirilowii, R. quadrifida, R. sachalinensis, and R. sacra. In this article, we will focus on R. rosea which is the most well known medicinal species.
Rhodiola is classified as an adaptogen and is used in traditional medicine to promote endurance, longevity and to alleviate fatigue and depression.
Rhodiola is classified as an adaptogen as it is claimed to meet the three defining features of adaptogens:
- Causes a non-specific increase in resistance against multiple stressors including physical, chemical, or biological agents
- Normalizes physiology regardless of the direction of change from physiological baseline caused by stressors
- It only influences normal body functions to the extent required to gain non-specific resistance (1).
Wow, that sounds great. I definitely want to know more.
- organic acids (gallic acid, caffeic acid, and chlorogenic acid),
- flavonoids (catechins and proanthocyanidins),
- tannins and
- phenolic glycosides (rhodioloside, rhodioniside, rhodiolin, rosin, rosavin, rosarin, and rosiridin).
The glycosides are mission-critical for Rhodiola and are believed to be responsible for its alleged adaptogenic properties.
The other key ingredient worth mentioning is p-tyrosol which is a potent anti-oxidant.
It is unclear as to how exactly Rhodiola might work. Some authors think that Rhodiola might influence neurotransmitters and stress hormones (2). Abstracts of untranslated Russian work suggest that Rhodiola might work via induction of opioid peptide biosynthesis (3).
The dosing strategy for Rhodiola is interesting and deserves a special mention.
Firstly, the dosing of Rhodiola is based on the specific standardization in the product being used. As an example, a dose of 360-600 mg Rhodiola Rosea daily is taken when using an extract standardized for 1% rosavin. However, a different dose would be used if a formulation contained 3% rosavin.
Secondly, Rhodiola is not taken continuously but for periods of time with breaks in between.
Rhodiola is typically taken several weeks prior to a period of expected increased physiological stress and continued throughout the duration of the challenging event or activity.
I have seen references to taking Rhodiola at three times the normal dose for acute challenges eg exams or matches) (1). However, as we will see the data does not always support this dosing strategy.
There are 162 Rhodiola products for sale on Amazon. The typical cost of a 500mg tablets containing 3% salidrosides and 1% rosavins is about $0.20.
Is There Any Research?
There are only 814 accessible publications on Rhodiola which includes just 45 clinical trials. The true research base for Rhodiola is not limited to these 814 publications. Rhodiola has been extensively studied in Russia over the last 50 years but unfortunately, the majority of this research is unavailable to us (1).
Does Rhodiola Help Burn Belly Fat?
Researchers from the Department of Animal Sciences in New Jersey studied a combination of Citrus aurantium (bitter orange) plus Rhodiola on diet-induced obesity in rats (4). Following a ten-day treatment intervention, the combination did not affect body weight or feeding patterns but did result in a 30% decrease in visceral fat weight.
As a die-hard fan of NCIS (forgive the unintentional pun), I am intrigued by the grim autopsy details in some of these studies.
In this study, the animals were decapitated in different rooms to minimize stress on the animals. I think that the motivation here had nothing to do with the humane treatment of animals but was driven by the fact that the researchers were measuring blood levels of brain stress chemicals.
Quantification of abdominal fat in the rats was done using a mid-abdominal incision on each carcass to identify and remove subcutaneous, retroperitoneal, and epididymal fat. The epididymis is part of the testes. (Honestly, not a job I could ever do. Not even for a Nobel Prize).
Another fascinating rodent study from Italy looked at Rhodiola in binge-eating rats (5). Yes, such a thing exists. Rats can be turned into binge eaters by three 8-day cycles of food restriction/re-feeding.
The study compared the effects of Rhodiola versus its two active principles, salidroside or rosavin, on binge eating. The study showed that Rhodiola and its active principle salidroside, but not rosavin, reduced or abolished binge eating.
Another rat study from the same university in Italy looked at rats with stress-induced anorexia (6). Yes, such a thing does exist. How do you stress a rat to the point of anorexia? It turns out that you have four options:
immobilization for one hour
injection stress hormone directly into the brain
injection of bacterial toxin directly into the abdomen or
injection of an antidepressant directly into the abdomen.
I am not judging here - but who on earth dreams up these studies? Rhodiola did reduce the anorectic effects of immobilization and injection of hormones into the brain but did not help with anorexia due to injections into the abdominal cavity.
Finally, Japanese investigators noted that rhodionin and rhodiosin from Rhodiola can block the activity of an enzyme called lipase in mice which in turn resulted in lower levels of triglycerides after eating (7).
The Japanese investigators speculated that Rhodiola could prove to be useful in lifestyle-related diseases such as obesity.
We only have laboratory rodent data to guide us at this stage on the effects of Rhodiola on body fat.
Does It Increase Energy and Athletic Performance?
This is a really interesting area.
One study, in particular, stands out (8). This study directly compared Rhodiola intake with placebo on endurance exercise performance. The study had two parts. In the first part, the study subjects took a once-off dose of Rhodiola or placebo and underwent testing (acute phase). In the second part, the study subjects took Rhodiola for 4 weeks (chronic phase) and underwent testing.
The results showed that the acute Rhodiola ingestion improved endurance exercise capacity in young healthy volunteers. Chronic dosing with Rhodiola did not improve on the improvement noted in the acute phase. This calls into question the standard dosing schedule that was mentioned in an earlier section of this article.
Canadian researchers carried out a systematic review of available evidence in relation to the 'efficacy and safety of Rhodiola Rosea for physical and mental fatigue' (9).
Carried out in 2012, the systematic review found only 11 suitable studies for analysis and concluded that the results were at-times contradictory but acknowledged that ‘some evidence suggests that the herb may be helpful for enhancing physical performance and alleviating mental fatigue’.
Since the publication of the 2012 review, Dun and colleagues carried out a study that looked at the effects of exercise plus Rhodiola sacra (10). The study looked at exercise capacity and exhaustive exercise in mice.
The mice exercised by swimming. The oddest part of the article stated that ‘the mice were dried gently with towels and a blower and returned to their cages’. Seriously? The mice had better living conditions than me.
Sign me up now to be a laboratory mouse. Actually, please cancel my application to be a laboratory mouse. I just read what happened during the ‘exhaustive exercise’ part of the protocol.
This involved swimming ‘until exhaustion, as defined as the failure to rise to the surface of the water to breathe within a 7-second period’. The combination of exercise plus Rhodiola improved exercise capacity in mice and protected against skeletal and cardiac muscle damage.
Despite the positive outcome, the fact that this paper involved mice and used a non-rosea species of Rhodiola means that this paper is not a game-changer.
Another more recent publication looked at acute dosing of Rhodiola on endurance exercise performance (11). A total of 18 subjects completed a 6-mile time trial in this study. The study had a double-blind, randomized, crossover design.
Subjects completed the time trial faster in the Rhodiola arm than during the placebo arm of the study. Additionally, the rate of perceived exertion was lower when taking Rhodiola. Plasma cortisol was also measured but no effects of Rhodiola were noted on blood cortisol levels.
A related and interesting study (well, interesting to me as an infectious disease physician) looked to see if Rhodiola can protect against viral infections in marathon runners (12). Transient immunosuppression can occur during prolonged intense exercise.
Marathon runners were given Rhodiola for 30 days prior to, the day of, and 7 days after, a marathon. Blood was drawn and tested against bacteria and viruses in a laboratory.
This very theoretical study showed that Rhodiola inhibited viral but not bacteria growth. This is interesting but is too far removed from actual reality to be practically useful.
There is some evidence that Rhodiola can help with physical performance.
Does It Help Balance Cortisol Levels?
There are two key studies to look at here.
Let’s start with rabbits. Swedish investigators studied the effects of placebo, rhodioloside (aka Rhodiola), Eleutherococcus senticosus, Schizandra chinensis, Rhodiola rosea, Bryonia alba and Panax ginseng over a 7 day period (13).
Male Chinchilla rabbits were sourced from Armenia and ‘all animals were clinically examined upon arrival and any that showed signs of abnormality or disease were excluded’.
I wonder if ‘excluded’ is a euphemism? The rabbits that passed the quality control test then received the test agent and underwent forced immobilization for 2 hours (as a form of stress) on day 2 and day 8 of the study.
I think that the whole area of ethics in relation to animal research is very interesting. This study adhered to an EEC Directive 75/318 (1994) in relation to laboratory animal care. The authors mention that they drew blood as opposed to looking at the brain as this eliminated the need for killing the rabbits.
That sounds nice until later in the paper, they mention that they took blood directly from the heart cavity. I wonder if some rabbit researchers have an alter ego that brings their kids to see Peter Rabbit in the movies on Saturdays afternoons and throws popcorn at Mr. McGregor?
I have to admit that I got hopelessly lost in the study methodology. Somewhere in the discussion, the authors refer to measuring blood levels in rats. I scrolled up and down but have no idea where the rats came from. I wonder if this was a typo - rat instead of rabbit?
I am not loving this study but let’s look at the results. There was no increase in cortisol levels in the rabbits who received adaptogens. Among the adaptogens, Rhodioloside, extracts of S. chinensis and R. rosea were the best at normalizing cortisol.
Now to humans. Polish investigators studied the effects of either R. rosea extract or placebo 26 healthy male students (14). The students were assessed (mentally and physically) before and after 4 weeks of either the Rhodiola or placebo.
The physical test involved cycling to fatigue in the morning following a 12 h overnight fast, at air temperature between 19°C and 21°C and with 40%–60% relative humidity. The mental test involved reacting to a visual cue and pressing a matching reaction key. Rhodiola ingestion was not found to affect physical performance.
Interestingly, Rhodiola did improve the results of some psychomotor tests (speed and accuracy) in this study. Simultaneous measurement of blood showed that the improvements in mental performance were not to be related to changes in cortisol or antioxidant levels.
The 6-mile time trial exercise study mentioned above showed no effects of Rhodiola on cortisol levels (11).
There is some evidence from a not-so-great rabbit study showing that Rhodiola (and other adaptogens) can prevent cortisol rises in response to stress. However, two human studies show no effects.
Does It Fight Depression and Anxiety?
Researchers from Philadelphia conducted a head-to-head study comparing Rhodiola with sertraline for major depression (15). The study was well-designed and involved 57 subjects over 12 weeks who were randomized to either Rhodiola or sertraline or placebo.
The study showed that Rhodiola was not as effective as sertraline in relieving depression but that Rhodiola was better tolerated than sertraline.
French GPs studied the effects of 6 weeks of supplementation with both Rhodiola and saffron extracts (one tablet, 154 mg of Rhodiola and 15 mg of saffron) (16).
This was an observational study which in some ways makes it less scientifically robust. On the other hand, a GP observational study is very real-world which is a major plus.
The study showed a significant decrease in the severity of depression in 45 patients who had been diagnosed as mildly to moderately ill at inclusion.
The treatment was very well tolerated. It is worth noting that most pharmaceutical antidepressant drugs have their onset of action at about 12 weeks.
This saffron-rhodiola blend had an earlier onset of action which supports the idea that it has a different mode of action that standard pharmaceutical medications for depression.
British researchers studied Rhodiola versus no treatment in 80 mildly anxious study participants (17). The Rhodiola arm of the study was noted to have statistically significant reductions in self-reported anxiety, stress, anger, confusion and depression and significant improvements in total mood.
Again these changes were noted after just 14 days of treatment. Even though these changes happened relatively quickly (ie less than the 12 weeks that a regular antidepressant would take), the benefits were noted gradually over those two weeks. This was interpreted by the authors as evidence that this was not just a placebo effect.
Psychiatrists from UCLA carried out a pilot study of Rhodiola for generalized anxiety (18). The study participants received Rhodiola supplementation daily for 10 weeks and were noted to have statistically significant improvements in their symptoms.
Again, this study is limited by small numbers and the absence of a control arm. However, it does provide us with clinically useful data.
Finally, a 2011 literature review of herbal medicine for psychological conditions found preliminary positive evidence that Rhodiola may help with depression (19).
There is evidence in the scientific literature to suggest that Rhodiola can help with mild to moderate depression and anxiety.
All patients with symptoms suggestive of psychological or psychiatric disorders should be evaluated by a medical professional in order to rule out treatable physical conditions that can mimic depression or anxiety and to ensure that the patient receives the very best of care. Neither depression nor anxiety, are amateur sports for DIY enthusiasts.
Does It Improve Brain Function?
Rhodiola was shown to prevent neurodegeneration, improve locomotion, and increase lifespan in the fruit fly (20).
In the UK study mentioned above in which Rhodiola was noted to relieve anxiety and boost mood, no relevant differences in cognitive performance between the groups were observed (17).
Students in Iraq received either a placebo, Ginkgo, Rhodiola or a combination of Gingko plus Rhodiola in a ten-week study designed to assess effects on a range of cognitive tests including short term memory (21).
The combined effect of Rhodiola plus Gingko Biloba had a more significant effect on cognitive function than either agent when used alone or placebo.
The issue of burnout is really topical in medicine right now. Burnout is way too common in medical professionals these days and is also seen in patients in medical clinics all over the world on a daily basis. German and Austrian investigators studied Rhodiola over 12 weeks in 118 outpatients suffering from burnout (22).
Statistically significant improvements in symptoms of fatigue, harassment, irritability, overload, tension, worry, depersonalization, and emotional exhaustion were noted but not for feelings of involvement and personal accomplishment. Statistically significant improvements were also noted in sexual health.
Specifically, statistically significant improvements in the enjoyment of sex, the ability to become sexually aroused and frequency of sexual activity was noted. It was not all Fifty Shades of Grey - there was no statistically significant change in the ability to have an erection or orgasm.
One study showed that Rhodiola may offer a range of benefits (and fringe benefits, if I may say) in people suffering from burnout.
One Last Thing: Rhodiola & Cocaine
Rhodiola was studied in cocaine-addicted mice but was not found to affect the hyperactivity and rewarding effects of cocaine (23). Sometimes the really interesting part of a medical research project is found in the small print and not in the abstract.
Firstly, the idea of inducing cocaine addiction in mice is bewildering. Secondly, the very fact that cocaine can be bought for medical research is equally amazing to me.
Is Rhodiola Rosea Safe?
There is too little reliable information to allow safe recommendation of Rhodiola in pregnancy or breastfeeding.
In the head-to-head study of sertraline versus Rhodiola, no patients discontinued Rhodiola (15). In the Rhodiola arm, no clinically significant changes were noted in BP, heart rate, weight or laboratory values.
A 2016 study in Europe suggested that a large number of commercially available Rhodiola Rosea products were actually adulterated with other species of Rhodiola (24).
Finally, Rhodiola has the ability to interact with important prescription drugs such as phenytoin and warfarin (coumadin) and should be avoided in patients in these medications (25).
Reading the research on Rhodiola, it sounds like it is drawn from the ingredients of a witches spell.
'Take the testicle of rats, blood drawn from the heart of a rabbit and gently blow-dry a mouse (before trying to drown it)'.
Despite all this and the fact that there is relatively little data, there is at least some evidence that suggests that Rhodiola might just be useful for some of the symptoms of asthenia such as mild anxiety and fatigue.