A summary of published research, not medical advice. See the Disclaimer.
Studies: every indexed trial and review on this topic, scored
Rhodiola rosea (rose root, golden root) is a flowering plant from cold, mountainous regions. Its root extract is sold as a herbal supplement.
Best-supported effect: Less mental fatigue in adults under work stress or with stress-related fatigue. Unclear: trials disagree (weak evidence).
Most-cited weak claim: Better endurance exercise performance. Unclear: trials disagree (weak evidence).
How we grade evidence · Last reviewed: October 2026
What you need to know
No effect of rhodiola has more than weak evidence. Trials of mental fatigue under stress were small and pointed in opposite directions, and a review rated every included trial at high or unclear risk of bias. Trials of endurance performance and of depression disagree with each other. No serious adverse events were reported in trials of 2 to 12 weeks. In 13 healthy volunteers, 14 days of rhodiola slowed the CYP2C9 breakdown of losartan, and one case report describes suspected serotonin syndrome after rhodiola was added to paroxetine. Trials enrolled adults only, and the EU herbal monograph states that safety in pregnancy and breastfeeding has not been established. Fatigue and mood trials used standardized root extracts for 2 to 6 weeks, at doses such as 400 mg or 576 mg a day.
No effect reaches "Probably helps" yet.
| Claim | Verdict | What was measured | Studied in |
|---|---|---|---|
| Less mental fatigue under stress | Unclear: trials disagree (weak evidence) 3 of 5 trials in one review found less fatigue, a later trial found fatigue got worse |
Self-reported | Adults with stress-related fatigue; physicians on night duty; nursing students on shift work |
| Endurance and exercise performance | Unclear: trials disagree (weak evidence) Mostly small trials in healthy adults, some better, others no effect |
Measured | Healthy adults, mostly men, trained and untrained |
| Depression symptoms | Unclear: trials disagree (weak evidence) 6-week trial in 89 adults found a benefit, 12-week trial in 57 found none |
Self-reported | Adults with mild to moderate depression |
| Anxiety and stress symptoms | Unknown (very weak evidence) One small 2-week trial, participants knew what they got and rated it themselves, no placebo group |
Self-reported | People with mild anxiety |
| Recovery after ischemic stroke | Unknown (very weak evidence) Rests on 15 animal studies, not tested in humans |
Measured | Animal models only |
Mental fatigue: a 4-week trial in 60 adults with stress-related fatigue found less fatigue and better attention scores than placebo [1]. A double-blind crossover trial in 56 physicians on night duty, with 2-week treatment periods, found better scores on a combined mental-fatigue index [2]. A 6-week trial in 48 nursing students on shift work found fatigue got worse on rhodiola than on placebo [3]. A systematic review of 11 trials found that 3 of 5 mental-fatigue trials reported a benefit, and rated every included trial at high or unclear risk of bias [4]. Unknown (very weak evidence). Samples were small, risk of bias high or unclear, and results inconsistent.
Exercise performance: two reviews of human trials describe some studies with better endurance or lower perceived effort and others with no effect [5][6]. One review found that single doses before exercise helped endurance, while daily dosing helped anaerobic performance but not endurance [5]. Most trials were small, and many tested a single dose before exercise. Unclear: trials disagree (weak evidence). Risk of bias was high or unclear.
Depression: a 6-week trial in 89 adults with mild to moderate depression reported significant symptom improvement on rhodiola but not on placebo [7]. A 12-week trial in 57 adults with mild to moderate major depression found no statistically significant difference from placebo or from sertraline [8]. Unclear: trials disagree (weak evidence). The two trials point in opposite directions, and the positive one ran under 8 weeks.
Anxiety: one 2-week trial in 80 mildly anxious participants reported less self-rated anxiety and stress [9]. The comparison group received no treatment, not a placebo, so participants knew their group. Unknown (very weak evidence). One small unblinded trial with a self-rated outcome.
Stroke: the claim rests on a meta-analysis of 15 animal studies reporting smaller brain injury and better neurological scores [10]. None of the studies cited here tested it in humans. Unknown (very weak evidence): animal data only.
The "adaptogen" claim, that rhodiola raises general resistance to stress, has not been tested as a single measurable outcome in human trials.
Shown in humans
Shown only in animals or cells
Theory only
| Side effect | Verdict | How often vs placebo | Source | Studied in |
|---|---|---|---|---|
| Serious adverse events over 2 to 12 weeks | May not increase it (weak evidence) None reported in small, short trials not built for rare harms |
None reported in any group | [1][2][7][8] | Subjects with stress-related fatigue; 89 adults with mild to moderate depression |
| Any adverse event | Unclear: trials disagree (weak evidence) Higher rate than placebo in one trial, no difference in another |
30.0% vs 16.7% in one trial; no difference in another | [3][8] | 57 adults with mild to moderate major depression |
| Headache | Unknown (very weak evidence) EU herbal medicine summary lists headache, no frequency or placebo comparison |
Not reported | [24] | |
| Nausea, abdominal pain, diarrhoea | Unknown (very weak evidence) EU herbal medicine summary lists gut symptoms, no frequency or placebo comparison |
Not reported | [24] | |
| Skin rash, itching | Unknown (very weak evidence) EU herbal medicine summary lists skin reactions, no frequency or placebo comparison |
Not reported | [24] |
The trials were small and short and were not designed to detect rare harms. In the depression trial, 30.0% on rhodiola reported adverse events, compared with 63.2% on sertraline [8]. The EU herbal monograph lists headache, gut symptoms and skin reactions with frequency not known [24].
This lists what studies and labels report. A pharmacist or prescriber can say whether it applies to a specific person.
This lists what studies and labels report. A pharmacist or prescriber can say whether it applies to a specific person.
| Combined with | What happened | Verdict | Source | Studied in |
|---|---|---|---|---|
| Losartan (CYP2C9 substrate) | After 14 days of rhodiola, the metabolite-to-losartan ratio fell 21% in 13 healthy volunteers, showing slower CYP2C9 metabolism | May happen (weak evidence) Slower breakdown after 14 days in 13 healthy volunteers, one study |
[11] | 13 healthy volunteers |
| Warfarin, phenytoin (narrow-margin CYP2C9 substrates) | Flagged by the human study authors as possibly relevant; in rats, rhodiola did not change warfarin levels or clotting effect | Unknown (very weak evidence) Flagged by authors only, rats showed no warfarin change |
[11][14] | Rats |
| Caffeine, omeprazole, dextromethorphan, midazolam | No significant change in CYP1A2, CYP2C19, CYP2D6 or CYP3A4 activity in the same 13-person study | May not increase it (weak evidence) No enzyme activity change in one 13-person human study |
[11] | |
| Theophylline | No change in theophylline levels in rats | Unknown (very weak evidence) Rat data only, no change in levels |
[14] | Rats |
| Digoxin and other P-glycoprotein substrates | Extracts blocked CYP3A4 and P-glycoprotein in lab assays; losartan exposure nearly doubled in 6 rabbits | Unknown (very weak evidence) Lab tests plus a losartan study in 6 rabbits |
[12][13] | |
| Paroxetine and other antidepressants | One case of restlessness, trembling and suspected serotonin syndrome after adding rhodiola to paroxetine; extracts block MAO-A and MAO-B in lab assays | Unknown (very weak evidence) Report of a single patient plus lab enzyme findings |
[15][16] | 68-year-old woman |
The EU herbal monograph states that no clinically relevant interactions have been observed [24]. Salidroside alone showed no enzyme or transporter inhibition in lab tests at expected blood levels [22].
These are the amounts used in the studies. They are not recommendations.
Most fatigue and mood trials used standardized root extracts. Daily doses included one low-dose tablet for 2 weeks [2], 400 mg for 2 weeks [9], 576 mg for 4 weeks [1], 364 mg once or twice a day for 6 weeks [3], and 340–680 mg for 6 weeks [7]. Exercise trials used either a single dose of about 200 mg before testing or daily dosing for days to weeks [5][6].