Rhodiola is in this formula because it has the largest body of randomised human trials of any botanical used in this category. That sentence needs qualifying, and the rest of this page does the qualifying.

Rhodiola rosea is a small flowering plant of cold, high places — the Arctic, the mountains of Scandinavia, Siberia and Central Asia. The part used is the root and rhizome.

An extract is not the plant. Root material is processed with a solvent to draw out its soluble compounds, then dried and concentrated. Two extracts of the same species can differ enormously depending on the solvent, the ratio of raw material to finished powder, and which compounds the process happens to favour.

This is why standardisation exists, and why section 2 matters more than it looks. Without a stated marker compound and percentage, “300mg of rhodiola” describes a weight of powder and nothing else.

The 3:1 figure is not derived from a clinical trial. It reflects the naturally occurring ratio of rosavins to salidroside in the root. Matching it establishes that the material is plausibly Rhodiola rosea rather than a related species. It does not establish that the extract behaves like the ones that were studied.

A regulator has ruled on precisely this point. In 2012 EFSA assessed a health claim for a rhodiola extract "standardised for rosavins and salidroside content" — materially our specification — and rejected it, on the grounds that the human studies offered had used extracts standardised differently and so were "not conducted with the food constituent under evaluation." A marker-profile mismatch was treated as disqualifying.

Why a stated specification matters. Rhodiola on sale varies widely. A 2018 study of seven commercial extracts found large differences in every marker it measured — one contained no rosavin at all — and a UCL analysis of rhodiola products concluded that adulteration with other species appears to be commonplace. A stated marker profile is how you check a product is what its label says. Ours is specified by our manufacturer at 3% rosavins and 1% salidroside.

Most of the meaningful trials used one of two proprietary extracts: SHR-5, owned by the Swedish Herbal Institute, or WS 1375, owned by Dr. Willmar Schwabe. We use neither.

Shevtsov 2003 — 161 military cadets, randomised, double-blind, placebo-controlled, SHR-5. A single dose, so it says nothing about taking it daily for weeks.

Olsson 2009 — 60 adults, randomised, double-blind, placebo-controlled, SHR-5 at 576mg daily.

Spasov 2000 and Darbinyan 2000 — small trials in students and physicians, both SHR-5. A systematic review grades the second inconclusive on methodological grounds.

Punja 2014 — nursing students, randomised, double-blind, placebo-controlled, at the University of Alberta, using a commodity extract at 2.8% rosavins.

• Our dose. The trialled doses cluster at 100, 170, 340–680 and 576mg. No trial has used 300mg, and the trials do not establish a dose-response relationship that would let anyone place it.
• Our extract. Most trials used SHR-5 or WS 1375. Ours is a commodity extract to the standard specification in section 2.
• Women as a group. There is no randomised trial of rhodiola in a women-only population, and none on any outcome specific to women.

There is no Cochrane review of rhodiola, and no systematic review has applied a formal certainty rating to it. So there is no certainty grade to quote.

What exists is two assessments of how the trials were run. A 2011 review noted "a lack of independent replications" and that "some of the primary studies were less than rigorous." A 2012 review applying the Cochrane risk-of-bias tool found that "none of the included studies are free of plausible bias," and could not perform a meta-analysis because no two trials had measured the same outcome.

And the claim rhodiola is usually sold on has been formally refused. Following the EFSA assessment described above, the claim was refused in law by Commission Regulation (EU) No 1066/2013, which is retained in Great Britain. This is not an unassessed claim awaiting a decision. It is an assessed claim that was rejected.

Most of the trials were funded by, or connected to, the companies that own the extracts being tested. SHR-5 is the Swedish Herbal Institute's extract, and researchers affiliated with the Institute are authors across much of its clinical literature, including the most-cited review of the field.

All five human studies of WS 1375 are on Schwabe's own extract, and four of the five are uncontrolled single-arm trials with no placebo group.

Punja 2014 was an academic trial at the University of Alberta.

• Rhodiola has no authorised health claim in Great Britain, and one claim for this standardisation has been formally refused. We make no claim for it.
• We do not claim our extract is the extract that was trialled. It is not, and we have no evidence it behaves the same way.
• We do not claim 300mg was chosen from a dose-response curve. No such curve exists, and no trial has used 300mg.
• We do not claim the research above describes what this product does.
• We do not claim this product treats, prevents or reduces the risk of anything.

What we claim is the composition: 300mg of Rhodiola rosea extract, standardised to 3% rosavins and 1% salidroside.

Who should not take this

Not suitable during pregnancy or breastfeeding. If you are taking medication or have a medical condition, speak to your GP or pharmacist before taking any supplement.