Rhodiola: Species Checks, Corrected Trials, and Mixed Results

What is rhodiola?

Rhodiola (Rhodiola rosea), also called golden root or arctic root, is a plant from cold mountain and Arctic regions whose root is used for tiredness and stress. Its marker compounds, the ones used to identify it and measure strength, are rosavins, found in Rhodiola rosea, and salidroside, which related species also contain.

People take rhodiola for fatigue, stress, mood, and exercise. In small trials of SHR-5, people reported less fatigue or burnout than on placebo, but reviews call the evidence contradictory, and a US depression trial did not find a significant benefit over placebo. The US National Center for Complementary and Integrative Health (NCCIH) says there is not enough evidence for any health use.

What the documented traditional use supports

The European Medicines Agency's 2024 assessment^[1] documents European medicinal use of specified rhodiola dry extracts since 1987, alongside a longer traditional context. It accepts traditional use for temporary stress symptoms such as fatigue and exhaustion, while finding the clinical trials too limited for well-established use.

NCCIH describes traditional use^[2] in Russia, Scandinavia and other parts of Europe for work performance, endurance, fatigue, depression and altitude sickness. Those uses help explain the modern marketing, but they do not establish that today’s capsule treats those conditions.

There is also a documented Soviet research history. A historical study of Tomsk^[3], drawing on published studies and interviews, describes intensive research from the 1960s through the 1980s. Animal experiments were followed by studies in medical-institute students and staff, then wider clinical programs. The historians also describe ethical and procedural problems. This history explains interest in the plant; it does not validate a modern product’s dose or turn the older trials into independent confirmation.

Modern studies use named extracts, fixed daily amounts and measured outcomes. That differs from an unspecified root preparation or a story about longevity. The useful comparison is whether a particular extract improves a particular symptom beyond placebo.

What people take rhodiola for

How rhodiola acts in the body is not well mapped; in small trials, people rated their fatigue or burnout lower. The EU accepts it as a traditional remedy for stress-related tiredness based on long use.

Some studies enrolled only men, including cadets and resistance-trained volunteers. They tested mental work or exercise, not testosterone, fertility or sexual function. The studies reviewed here do not settle whether rhodiola is better than ashwagandha for stress.

Results apply to the preparation and population studied.

When to ask a doctor before taking rhodiola

• You take losartan, warfarin or phenytoin. A small human study found a change in a drug-processing enzyme; the clinical consequences were not established. Have the prescriber or pharmacist review the combination.
• You take antidepressants or stimulants. Have the combination reviewed before adding rhodiola. An adjunct depression trial exists, but that does not make self-directed combinations safe or make rhodiola an antidepressant replacement.

Traditional-use directions and timing

The EU traditional-use monograph lists 144–400 mg of dry extract a day and calls for medical review if symptoms last more than two weeks. These directions are based on long use; they are separate from the SHR-5 trial regimens above, some of which exceed that range. The study amounts are not general dose advice. There is no official US daily amount.

Insomnia is a reported side effect, which is why labels often place rhodiola earlier in the day; trials have not established a best time. NCCIH's safety evidence extends to 12 weeks, while the EU advises medical review for symptoms lasting more than two weeks.

All extracts at a glance

An honestly labeled R. crenulata product is a different species; it becomes a substitution problem when sold as R. rosea.

What to pay attention to on the label

Which number on the label is the amount?

Look for Rhodiola rosea root extract in milligrams and a guaranteed percentage of rosavins, the group of markers used to identify the species. A salidroside percentage is useful additional information, but salidroside alone cannot identify Rhodiola rosea. One product lists 400 mg per two capsules standardized to 3 percent rosavins; its label names the species and rosavin amount even though it does not state salidroside. Those are label declarations, not independent confirmation of what is in the bottle.

Misleading labels

Products that are not Rhodiola rosea

A 2016 chemical survey^[4] tested about 40 commercial products aimed at European buyers. About a fifth of those claiming to be Rhodiola rosea contained no rosavin. Many others had lower rosavin levels than registered products and appeared adulterated with other species.

Salidroside-only labels

One product lists 200 mg of “Rhodiola root extract” standardized to 3 percent salidroside, without naming a species. Salidroside is found in several Rhodiola species, so it does not show the product is Rhodiola rosea. Another product is openly Rhodiola crenulata, a different species that was not tested in the trials described on this page.

Confusing servings and items per serving

Some manufacturers put 180 capsules on the front, and the back says 3 capsules per serving and 60 servings. The amount on the Supplement Facts panel is for the whole 3-capsule serving.

Does 3% rosavins and 1% salidroside guarantee a trial match?

No. That common specification describes two marker percentages. It does not establish the same extraction process, dose or effects as SHR-5, WS 1375 or another studied product. The 2015 SHR-5 depression trial reported a different marker profile. Even the two 2025 exercise papers used different profiles: one reported 3% rosavins and 1% salidroside; the other reported the reverse, without an independent composition assay. A marker percentage or certification logo does not show that a product will reproduce a trial’s clinical result.

CITES and sourcing

The entire Rhodiola genus has been listed in CITES Appendix II since 23 February 2023. This regulates international trade; it is not a blanket ban on buying rhodiola. The listing’s annotation excludes seeds, pollen and finished products packaged ready for retail. Raw roots and bulk ingredients are a different trade category. The current French CITES record^[5] and Canadian regulations^[6] document that distinction. The listing alone does not establish that every species or population is near extinction.

The retail exemption does not verify a product’s species or the origin of its ingredients. These are separate from its legal trade category.

Manufacturer claims and the studies they may be based on

A “reduces fatigue” or “supports stress resilience” line may point to small SHR-5 trials, often in special groups such as night-shift doctors. A “mood support” line may point to the 2007 depression trial, whose corrected results table remains unverified here; the 2015 US trial did not demonstrate a benefit over placebo.

Common Myths about Rhodiola

Is rhodiola a proven natural antidepressant?

No. A 2015 US trial of 57 adults did not find a significant benefit over placebo after 12 weeks, though it caused fewer side effects than sertraline, an antidepressant.

Does rhodiola cause weight gain or mess with hormones?

The 2015 depression trial measured weight and found no clinically meaningful change. A 2009 stress-fatigue trial reported a smaller rise in the hormone cortisol after waking with SHR-5, but that single finding does not establish a general hormone effect or a weight-loss benefit.

Drawbacks and side effects

There is no official upper limit. Side effects listed by NCCIH and the European Medicines Agency include headache, dizziness, insomnia, dry mouth, stomach upset, and skin rash. NCCIH says it is possibly safe for up to 12 weeks. That statement does not establish safety for indefinite use.

Rhodiola is not recommended for anyone under 18.

Mania and mood medicines

A 2022 case report^[7] described a 58-year-old man hospitalized with manic behavior after taking three times the product’s recommended amount. He also used other supplements; the report did not establish the exact rhodiola dose or test the product. His symptoms resolved during hospital care. This is a reason for caution, especially with a history of mania or bipolar disorder, but one case cannot tell us how often rhodiola causes mania or establish that usual doses easily trigger it. Discuss use with the clinician managing the condition.

What the medicine-interaction study actually measured

In a 13-person crossover study^[8], healthy volunteers took Arctic Root for 14 days before receiving medicines used to measure enzyme activity. The ratio of a losartan metabolite to losartan fell by 21%, suggesting reduced activity of CYP2C9, an enzyme that processes several medicines. The other four tested enzymes, including CYP3A4, did not change significantly.

The authors warned that even this modest change could matter for drugs such as warfarin or phenytoin, where small changes in exposure can matter. They did not demonstrate bleeding, loss of seizure control or dangerous drug accumulation. A laboratory prediction about drug transport also cannot be treated as a measured interaction in patients. Bring the exact supplement and medicine list to the prescriber or pharmacist.

Pregnancy

Little is known about rhodiola in pregnancy or breastfeeding, and the European Medicines Agency does not recommend it. Do not take it if you are pregnant or breastfeeding.

The science behind rhodiola

Rhodiola has been studied in several preparations and populations. Some comparisons favor an extract, others do not, and uncontrolled improvement is common in the burnout literature. The differences matter more than the umbrella term “adaptogen.”

Fatigue and stress: positive and negative trials

In a 2009 trial, 60 adults with stress-related fatigue took 576 mg of SHR-5 or a placebo for 28 days. Both groups improved, while SHR-5 did better on a burnout scale and some attention measures.

In a 2000 crossover trial of 56 doctors on night duty, the abstract reported a fatigue-index advantage for SHR-5 in the first two-week period. That narrower result should not become a claim of lasting relief from everyday tiredness.

A 2012 review of 11 trials called the results contradictory and judged every included trial open to design flaws that could skew the result.

A 2011 review noted that individual studies lacked independent replication at that time.

A later placebo-controlled trial in nursing students^[9] went the other way. Forty of 48 randomized students were analyzed after six weeks on an Alberta-grown extract or placebo. They took two 182-mg capsules daily, with an optional third; this was not SHR-5. Vitality and fatigue scores favored placebo. The small sample limits generalization, but it is a direct counterexample to the idea that any rhodiola extract reliably reduces fatigue.

WS 1375 has a different evidence base. Three open-label studies enrolled 101 people with stress symptoms^[10], 100 with prolonged fatigue^[11] and 118 with burnout symptoms^[12]. Participants took 200 mg twice daily for four, eight or twelve weeks. Scores improved, sometimes within the first week, but none of these studies had a placebo group. They cannot separate an extract effect from expectations, natural recovery or other changes during the study.

Depression: no clear benefit in the later trial

In a 2007 trial, 89 adults with mild to moderate depression took 340 or 680 mg of SHR-5 or a placebo for 6 weeks. A published correction changed the names of the depression scales and replaced the Beck Depression Inventory results table. Because the replacement numbers have not been verified here, this page treats the study’s depression result as unresolved. In a 2015 US trial, 57 adults took rhodiola, sertraline, or a placebo for 12 weeks; none of the three differed significantly.

A 2020 trial^[13] also tested Rhodiola capsules added to sertraline in 100 people. The abstract does not identify the species or extract composition well enough to apply its findings to the R. rosea products described here. It is not evidence that taking an arbitrary supplement with an antidepressant is safe.

Anxiety and everyday mood

In a study of 80 mildly anxious adults^[14], Vitano at 200 mg twice daily for 14 days was associated with better self-rated anxiety, stress and mood than no treatment. Cognitive outcomes did not show a relevant difference. Without a placebo, participants knew whether they were taking something, so expectations could influence their answers.

For diagnosed generalized anxiety disorder, a 10-person pilot^[15] reported improved anxiety scores over ten weeks at 340 mg daily. It had no comparison group. Together, these findings justify further testing; they do not establish rhodiola as an effective anxiety treatment.

Exercise: results depend on the test

Exercise findings depend on the test. In a 2021 crossover study of ten resistance-trained men^[16], three days at 1,500 mg daily plus a 500-mg pre-exercise dose increased bench-press movement speed, but participants completed fewer total repetitions than with placebo. Faster movement was not better endurance.

A 2025 study with 27 completers^[17] tested 200 or 1,500 mg daily for seven days. The lower dose improved bench-press repetitions and lifting volume compared with placebo, and both doses improved the total score on a color-and-word task called the Stroop test. A cycling sprint test, perceived effort and heart-rate/blood-pressure measures did not show consistent benefits. The paper also contains inconsistencies between its tables and prose about maximum strength and dose ordering, which make its broad strength and dose-response conclusions uncertain.

Another 2025 crossover study^[18] tested RhodioZen at 1,200 mg daily for four days in 18 trained adults. There was no overall supplement effect on strength measures and no clear improvement on the cognitive tests. A few individual exercise sets favored rhodiola after a control video, rather than after a mentally fatiguing task. Several authors advised the product or supplement companies. These selected findings do not show a general ability to overcome mental fatigue.

Claims about improved muscle energy also have a direct human countercheck: a four-day study in twelve trained men^[19] found no significant improvement in muscle-energy recovery or time to exhaustion at 1,500 mg daily. A separate 15-person simulated-altitude study^[20] found no significant improvement in blood oxygenation. These are specific tests, not proof that every exercise use fails, but they limit broad energy and altitude claims.

Mechanisms and what remains uncertain

“Adaptogen” does not identify a single clinical effect. Proposed effects on the body’s response to stress, brain chemicals and energy production are explanations to investigate. They do not establish that capsules prevent energy depletion, normalize hormones or protect the human brain. The seven-day 2025 exercise study measured performance, but did not test these proposed explanations for its results.

The practical uncertainty is which verified preparation helps which symptom, by how much, and for how long. Small positive trials, negative comparisons and uncontrolled studies answer different parts of that question.

What you may have heard on podcasts

Andy Galpin (Huberman Lab, 22 February 2023), an exercise scientist, said rhodiola gives “somewhere between a small benefit to little benefit” and is rarely harmful, and that it may help manage cortisol, though lowering cortisol when it is already low could worsen tiredness. He recalled two studies suggesting it might reduce muscular endurance. Andrew Huberman said he takes it before hard training. Neither gave an amount.

Galpin's assessment is more definite than the reviews, which found contradictory evidence rather than an established small benefit. His broad “rarely harmful” reassurance is not established by these short trials. The exercise studies above also show why movement speed, repetitions and cognitive scores need separate treatment.

The bottom line

Rhodiola has some positive stress-fatigue findings, but the studies are small and contradictory. The depression evidence is not strong enough to turn a traditional fatigue remedy into a reliable antidepressant.

Most trials described here concern Rhodiola rosea extracts; an unspecified “rhodiola” or isolated salidroside product may have a different composition. Persistent fatigue also warrants assessment of its cause.

Source notes

• National Center for Complementary and Integrative Health: rhodiola^[2]
• ^[21]
• ^[1]
• ^[22]
• ^[23]
• ^[24]; ^[25]
• ^[26]
• ^[27]
• ^[28]
• ^[29]
• ^[30]
• ^[31]
• ^[32]
• ^[33]

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