Overview
This study is the first peer-reviewed investigation of heavy metal contamination levels in Rhodiola rosea dietary supplements sold on the U.S. market, alongside analysis of biomarker compound content (rosavins and salidroside) and pesticide residues. Ten products (seven capsular, three tinctures) were purchased from Amazon in 2024 and analyzed at Eurofins Scientific laboratories using ICP-MS for heavy metals (As, Cd, Co, Pb, Hg) and GC-MS or LC-MS for pesticides. All seven capsular products contained detectable arsenic, cobalt, and lead; pesticide residues were below detection limits in all ten products; tinctures showed no detectable metals.
Key numbers
Heavy metal concentrations in capsular products (ppb; LOQs: Cd, Hg, Pb = 5 ppb; As, Co = 10 ppb):
| Sample | As [ppb] | Cd [ppb] | Co [ppb] | Pb [ppb] | Hg [ppb] |
|---|---|---|---|---|---|
| Capsule 1 | 22.8 | 34.7 | 46.4 | 75.1 | <5 |
| Capsule 2 | 54.4 | <5 | 50.8 | 11.6 | <5 |
| Capsule 3 | 21 | <5 | 18 | 9 | <5 |
| Capsule 4 | 159 | 22 | 164 | 88 | <5 |
| Capsule 5 | 393 | 11 | 733 | 85 | <5 |
| Capsule 6 | 65.8 | <5 | 40.8 | 43.8 | <5 |
| Capsule 7 | 59.7 | <5 | 106 | 55.2 | 10.9 |
| Tincture 1 | <10 | <5 | <10 | <5 | <5 |
| Tincture 2 | <10 | <5 | <10 | <5 | <5 |
| Tincture 3 | <10 | <5 | <10 | <5 | <5 |
Arsenic ranged from 21 to 393 ppb across capsules; Capsule 5 at 393 ppb and Capsule 4 at 159 ppb were the highest. Cobalt ranged from 18 to 733 ppb; Capsule 5 at 733 ppb and Capsule 4 at 164 ppb were notably elevated at more than 6.5-fold and 14-fold above median, respectively. Lead ranged from 9 to 88 ppb. Cadmium detected in three of seven capsules at 11, 22, and 34.7 ppb. Mercury detected only in Capsule 7 at 10.9 ppb.
Per-serving estimates from the authors: Capsule 5 (500 mg serving) contributed approximately 200 ng arsenic and 360 ng cobalt per serving; Capsule 4 (250 mg serving) contributed approximately 40 ng arsenic and cobalt per serving.
Methods
ICP-MS (Agilent 7900) following AOAC methods 2015.01, 2011.19, and 993.14 with microwave acid digestion using HNO3. LOQs: 5 ppb for Cd, Hg, and Pb; 10 ppb for As and Co. Pesticide analysis via QuEChERS extraction followed by GC-MS and LC-MS (70 USP chapter <561> analytes). Arsenic speciation was not performed; the reported values are total arsenic (tAs), not inorganic arsenic (iAs). The authors note that speciation would be required to assess whether products 4 and 5 exceed HHS minimal risk levels for inorganic arsenic.
Implications
Certification: Rhodiola rosea as a botanical supplement ingredient is a high-metal-risk ingredient based on this data. The tAs values in capsule products (up to 393 ppb in the supplement matrix as-sold) are substantially elevated; iAs speciation would be needed to assess inorganic fraction. Capsule products warrant higher scrutiny than tinctures when assessing supplements containing this ingredient. Cobalt at 733 ppb in a single commercial product is a notable finding outside the HMT&C 10-analyte panel.
Courses: Illustrates supplement adulteration risk and the gap between regulatory oversight of botanicals and that of pharmaceuticals; useful case study for supplement quality control modules.
App: Rhodiola rosea as an ingredient maps to the botanical supplement category with elevated tAs, Pb, and Co signals for capsule-form products; tincture form shows significantly lower risk.
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Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |