Ingredients · Botanicals
Rhodiola
Rhodiola rosea — adaptogen mechanism, the SHR-5 fatigue data, and why eleven trials still don’t settle the question.
In one paragraph: the standardised Rhodiola rosea extract SHR-5, at 576 mg/day for 28 days, outperformed placebo on burnout scores and attention indices and blunted the cortisol awakening response in people with stress-related fatigue. Across the wider literature of eleven trials, however, results are contradictory and risk of bias is high or unclear throughout. It is a defensible ingredient for a fatigue-positioning product only if you match the extract specification and dose to the trial that worked.
Mechanism
Rhodiola is classified as an adaptogen: the proposed mode of action is modulation of the hypothalamic–pituitary–adrenal axis rather than a direct stimulant effect. The strongest human signal for that mechanism is the blunted cortisol awakening response reported in the SHR-5 trial, which is consistent with an effect on stress-response regulation rather than on arousal.
Salidroside and rosavin are the constituents most often standardised against. Note that “Rhodiola extract” on a specification sheet tells you very little — the trial evidence attaches to specific standardised extracts, not to the species.
Human endpoint data
The Phase III trial by Olsson and colleagues randomised subjects with stress-related fatigue to SHR-5 576 mg/day or placebo for 28 days. The extract beat placebo on burnout scoring and on attention indices, alongside the cortisol finding.
The systematic review by Ishaque and colleagues assembled eleven trials of Rhodiola for physical and mental fatigue. Its conclusion is the one that matters for a formulator: the results are contradictory, and every included trial carried high or unclear risk of bias. A single positive Phase III result inside a body of eleven inconsistent trials does not make a strong claim.
What this means for formulation
- Match the extract, not the plant. If you are relying on the SHR-5 data, your specification needs to correspond to that extract and that daily dose. Substituting an unrelated Rhodiola extract discards the evidence you were citing.
- Position on stress-related fatigue, not on energy. The trial population had stress-related fatigue. Extrapolating to general energy or athletic performance is not supported by the cited work.
- Expect the risk-of-bias question. Any competent regulatory reviewer will find the Ishaque review. Address it in your dossier rather than citing only the positive trial.
- Check interactions in your market. Combination products should be screened for CYP interaction data before launch.
Where the evidence is thin
There is no adequately powered independent replication of the SHR-5 fatigue result that resolves the inconsistency across the eleven trials. Until one exists, Rhodiola stays at Moderate claim readiness on our scale: real trial evidence, real limitations, not a settled question.
References
- Ishaque S, Shamseer L, Bukutu C, Vohra S. Rhodiola rosea for physical and mental fatigue: a systematic review. BMC Complementary and Alternative Medicine. 2012. Systematic review. PMID 22643043 · 10.1186/1472-6882-12-70
- Olsson EM, von Schéele B, Panossian AG. A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract SHR-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue. Planta Medica. 2009. Phase III randomised controlled trial. PMID 19016404 · 10.1055/s-0028-1088346
Educational content for industry professionals. Not medical advice and not an approved health claim. See our evidence methodology.
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