Rhodiola vs Iron

for energy / fatigue

Stronger evidence: Iron

Stronger effect: Iron

Safety: Rhodiola carries a uncertain interaction; Iron has none recorded.

For energy / fatigue, Iron has the stronger evidence grade.

Rhodiola

grade C low certainty

small reductions in fatigue in stressed adults; studies are short and small

Iron

grade A high certainty

reliably reduces fatigue when iron deficiency / IDA is present; no benefit when iron-replete

18–65 mg/day, iron-deficient adults (esp. menstruating women)
sources: PMID:00000031 · PMID:10000007