The average dose of R. rosea is between 200 mg and 400 mg per day of an extract that is standardized to contain rosavins and salidrosides in a 3:1 ratio. This mimics the ratio of these compounds that naturally occur in R. rosea root.
Purchasing only R. rosea is important, as it is this species of rhodiola that has been the predominant subject of phytochemical, animal, and human studies. While salidrosides are found in all species of rhodiola, only R. rosea contains rosavins (rosavin, rosin, and rosarin). “Approximately 51% of all animal studies and 94% of all human studies conducted on plants in the genus rhodiola are on the species R. rosea,” notes health journalist Carl Germano, RD, CNS, LDN. He adds, “Only R. rosea has passed extensive toxicological studies and has been certified safe for both animals and humans.”
Rhodiola is generally considered safe and well tolerated, although high doses (1.5-2.0 g/day) have been associated with irritability. Rhodiola rosea may have a mild energizing effect, so it should be taken first thing in the morning or during midday. The herb is best taken without food. Rhodiola’s effects in pregnant and nursing women have not yet been studied, so these women should not use the herb until more information is available.