Evidence explainerRhodiola rosea

Rhodiola Side Effects: Dizziness, Insomnia and a Drug-Enzyme Interaction

NCCIH calls rhodiola possibly safe for up to 12 weeks. The bigger caution is an enzyme effect that matters for some prescription drugs.

By Kymata Health editorial teamPublished October 9, 2026Last reviewed October 9, 2026

Medical review pending. Written by our editorial team from the studies cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • NCCIH says rhodiola is possibly safe for up to 12 weeks [1].
  • Reported side effects include dizziness, headache, insomnia and either dry mouth or excess saliva [1].
  • 14 days of a commercial rhodiola product lowered CYP2C9 enzyme activity by 21% in 13 healthy volunteers [2].
  • NCCIH notes reported interactions with losartan, a blood-pressure drug [1].
  • Little is known about rhodiola during pregnancy or breastfeeding [1].

The evidence, graded

Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.

  • Grade DImprovedFatigue and attention scoresRhodiola rosea · RCT · n=60 · 2009 · PMID 19016404Both groups improved (placebo effect), but SHR-5 beat placebo on a burnout scale and several attention measures and changed the cortisol response to waking. No serious side effects attributed to the extract were reported.
  • Grade CNo effectMuscle damage, soreness and inflammation after a marathonRhodiola rosea · RCT · n=48 · 2014 · PMID 24055627No difference from placebo in race time, loss of jump height, muscle soreness, muscle-damage markers, cytokines or heat shock protein 72.

Common side effects

NCCIH lists dizziness, headache, insomnia, and either dry mouth or excessive saliva production as possible side effects, and calls rhodiola possibly safe for up to 12 weeks [1].

In a 28-day trial of an extract at 576 mg/day, no serious side effects attributed to the extract were reported [3].

The enzyme interaction

In a crossover study, 13 healthy volunteers took a commercial rhodiola product for 14 days before a cocktail of test drugs [2]. Rhodiola reduced CYP2C9 activity by 21%, measured with losartan, and had no significant effect on four other drug-processing enzymes [2].

The authors describe the effect as modest [2]. NCCIH also notes that interactions between rhodiola and losartan have been reported [1]. Anyone taking prescription medicines should ask a pharmacist before using rhodiola [1].

Who should be careful

Little is known about whether rhodiola is safe in pregnancy or while breastfeeding [1]. NCCIH also notes that depression can be a serious illness and that anyone who may have it should consult a health care provider [1].

For what the trials found on benefits, read rhodiola rosea benefits.

Quick answers

Can rhodiola cause insomnia?

NCCIH lists insomnia among possible side effects [1].

How long can rhodiola be taken?

NCCIH describes it as possibly safe for up to 12 weeks [1].

Does rhodiola interact with blood-pressure medicine?

Interactions with losartan have been reported, and rhodiola lowered the activity of the enzyme that processes it by 21% in a 14-day study [1][2].

Keep reading

Full monographs

Related articles

Browse the full Supplement & Nutrient Encyclopedia or all supplement articles.

References

  1. [1]Rhodiola (last updated April 2025). National Center for Complementary and Integrative Health, 2025.
  2. [2]Effect of commercial Rhodiola rosea on CYP enzyme activity in humans. Eur J Clin Pharmacol, 2016. PMID 26613955
  3. [3]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 Med, 2009. PMID 19016404

Rhodiola rosea and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.