Rhodiola

Sold as an “adaptogen” for tiredness and stress, alone or in “energy” and “stress” blends. Its trials contradict each other and every one has design flaws, so we cannot tell you whether it works.

At a glance

Our verdict	Contradictory trials, all at high or unclear risk of bias.
Sold for	Stress and fatigue (claimed)
How sure the evidence is	Very low
Cost a month	About $20 to $40

Written for adults in Canada. It explains the evidence; it is not advice for you personally. Last reviewed 20 October 2026.

Supplement Check

Is it right for you?

Rhodiola is often sold inside “stress” B-complex products that carry far more vitamin B6 than our safe line. Your check adds up everything you take and tells you what to keep and what to stop. Our Supplement Check looks at:

Bipolar disorder.
Pregnancy and breastfeeding: no safety data
Anyone taking an antidepressant, another serotonin medicine or a stimulant
Anyone already taking a B-complex
Under 18: outside the Supplement Check, which is for adults
Every medicine you take

Coming soon. The Supplement Check and the Online Health Assessment open once our safety testing is complete.

$59 when it opens, paid once. Adults 18 and over, anywhere in Canada. While the service is new, Dr. French reads every report himself, and your report arrives within 3 working days. More about the Supplement Check

Tell me when it opens

What it is

Rhodiola rosea is a plant whose root extract is standardised to two marker compounds, rosavins and salidroside. It is sold on its own and in “adaptogen”, “energy” and “stress” blends, including some B-complex products. Commercial products often lack the marker compounds they claim.

Structure of Rhodiola — Structure: PubChem (public domain).

How it acts

It is proposed to act on the body's stress-hormone system (the hypothalamic–pituitary–adrenal axis), and in the test tube it blocks monoamine oxidase, an enzyme that breaks down mood chemicals such as serotonin. This is mechanism only. It has not been shown in people, and it is not proof that rhodiola works.

Outline of a person showing where Rhodiola acts in the body

What it is used for, and what the evidence says

Use	What the trials found	How sure we are
Physical and mental fatigue	A systematic review found 11 trials. About half were positive and half were not, and every trial had design flaws that put it at high or unclear risk of bias. [1] Results that contradict each other, from flawed trials, do not allow any firm conclusion.	Very low
Stress	The same contradictory trials at high or unclear risk of bias. [1] Our review rates it “not proven”.	Very low

How sure we are: High means further research is very unlikely to change the answer; Moderate, it might; Low, it may well change; Very low, we are very unsure. These follow the GRADE method that guideline panels use.

Benefits

Uncertain. No benefit for tiredness or stress has been shown reliably. [1]

Risks and side effects

Side effects: dizziness, dry mouth, poor sleep, irritability.
Vitamin B6 in blends. Canadian B-complex products named “with Rhodiola” give 200 mg of vitamin B6 a day. [2] Our line keeps total B6 from all products under 10 mg a day, because high-dose B6 can damage the nerves in the hands and feet (numbness, tingling); Health Canada has reviewed this risk. [3]
Unreliable products. Many lack the marker compounds on the label.

Interactions with medicines

It may change how the liver clears medicines. In the test tube, rhodiola blocks two liver enzymes, CYP3A4 and CYP2C9, that clear many medicines; whether this happens in people has not been measured. It also blocks monoamine oxidase in the test tube, which is a reason for caution with serotonin medicines.

Medicine	What can happen	What to do
Antidepressants and other serotonin medicines	Possible added effect (test-tube finding; not shown in people)	Do not take together without your doctor
Stimulants, including ADHD stimulants and caffeine products	Added stimulant effect	Do not take together
Medicines cleared by the liver enzymes CYP3A4 and CYP2C9	Levels could rise (test-tube finding; not measured in people)	Ask your pharmacist or doctor first
Any B-complex or other product containing vitamin B6	B6 adds up across products	Count the total; keep it under 10 mg a day

Who should not take it

Bipolar disorder.
Pregnancy and breastfeeding: no safety data.
Anyone taking an antidepressant, another serotonin medicine or a stimulant.
Anyone already taking a B-complex: count the vitamin B6 first.
Under 18: outside the Supplement Check, which is for adults.

Dose and timing

We do not recommend a dose. For reference, the usual range is 200 to 600 mg of extract a day.

No test tells you whether it is working. If you take a rhodiola blend, read the label for vitamin B6 and add it to any other product you take.

What we know about Canadians

No Canadian data on how many people take rhodiola in our review. What we do know is what the products contain: in a scan of every active Canadian natural health product licence (October 2026), B-complex products named “with Rhodiola” (Nestlé group brands) provide 200 mg of vitamin B6 a day, and 580 of 731 B-complex licences (79%) give 10 mg of B6 a day or more. [2] A Canadian label cannot be relied on to warn about it.

How sure are we: moderate. Health Canada licence database scan, 20 Oct 2026: licensed amounts, not what people actually take; no data on rhodiola use itself.

An honest comparison: tiredness and low energy

Same outcome (feelings of energy or fatigue), cost a month in Canadian dollars. Exercise trials cannot be blinded; supplement trials can.

Option	Effect	How sure we are	Cost a month (CAD)
Iron, only when iron studies show low iron stores	Less self-rated fatigue (standardised effect 0.38); fitness did not change [5]	Moderate	About $5
Rhodiola, or “energy” blends	Contradictory trials, all at high or unclear risk of bias [1]	Very low	$20 to $40
Find the cause first: sleep, sleep apnoea, mood, iron, vitamin B12, thyroid, alcohol, medicines	Treats the reason, where there is one	Not graded	Blood tests through the clinic
Regular exercise	More energy and less fatigue against no exercise (effect size 0.37), but no effect against a placebo control [4]	Low	$0 to $21
No medicine is used for unexplained fatigue	—	Not graded	—

Read honestly: for stress the picture is the same. An 8-week mindfulness-based stress reduction course lowered stress measurably (effect size 0.53, low to moderate certainty), [6] exercise lowered distress, [7] and no medicine is appropriate for stress without an anxiety or depressive disorder. Rhodiola is the only option on either list with no reliable effect.

Why we don't recommend it

We do not sell rhodiola and our check never recommends it. Its trials contradict each other and all have serious flaws, so we cannot tell you whether it works, and some blends carry a large dose of vitamin B6.

Already taking it? Stop it and tell your doctor if you have bipolar disorder, are pregnant or breastfeeding, or take an antidepressant or a stimulant. If you take a blend, check its vitamin B6. If tiredness is the reason you take it, the cause is worth finding first: sleep, mood, iron, vitamin B12 and thyroid.

Rhodiola has no reliable effect on tiredness or stress: about half of 11 trials were positive, and every trial was at high or unclear risk of bias. Exercise, sleep and finding the cause of tiredness have better evidence and cost little or nothing; for stress, a mindfulness course does measurably better. In the test tube it blocks liver enzymes and an enzyme that breaks down mood chemicals, a reason for caution with common medicines. A product we cannot show works, at $20 to $40 a month, is not one we sell. Dr. French approved this verdict with the 20 October 2026 evidence review.