Rhodiola

While some clinical trials have examined the effects of Rhodiola rosea on cognitive function, the quality of many were suboptimal and none have directly tested whether it can prevent age-related cognitive decline or dementia. Our search identified:

• 1 systematic review analyzing the effects of Rhodiola on physical and mental fatigue
• 5 randomized, controlled trials examining the effects of Rhodiola on cognitive function
• 2 open-label clinical trials: 1 in older adults and 1 in mildly anxious people
• Numerous preclinical studies

Rhodiola is reported to enhance energy levels and control how the body responds to stress, both of which can affect brain health, but the clinical evidence to support these assertions is lacking due to the low quality of many trials. No clinical studies have tested whether Rhodiola can prevent age-related cognitive decline or dementia. In one well-conducted randomized, controlled clinical trial in male students (17–19 years old), researchers found no improvement in cognitive scores after 20 days of supplementation [1]. And a double-blind cross-over study with 18 healthy adults prescribed 3 mg/kg of Rhodiola found no effects on mood or cognitive function [2]. A systematic review examining the role of Rhodiola on mental fatigue reported that it was effective in some studies while not in others, but methodological flaws in the studies precluded accurate assessment of its efficacy [3]. More rigorous randomized controlled trials are needed to determine the effect of Rhodiola on mental fatigue.

While preclinical studies have suggested potential benefits, the research is inconclusive. One study, for example, showed that Rhodiola can act as a powerful antioxidant, but was toxic to isolated neurons [4].

For Dementia Patients

There is no evidence that Rhodiola supplements can treat dementia. While there is some evidence that Rhodiola may help combat symptoms experienced by dementia patients, such as insomnia, fatigue, and anxiety [5-7], none of these trials included patients with dementia.

Rhodiola is considered generally safe for healthy adults [3]. Although rare, reported side effects include headache, mild dizziness, dry mouth, sleepiness, insomnia, hyperactivity, jitteriness, agitation, and diarrhea [8][9]. Safety has not been assessed extensively for treatment exceeding three months.

NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.

Rhodiola supplements are commercially available in both capsule and liquid forms. However, quality and composition of supplements can vary widely by manufacturer. Although there is no official recommended dose, clinical studies have used doses from 50 to 1500 mg/day with no reports of major adverse effects. Most commonly used doses that are proposed to be safe range from 200 to 600 mg/day [8].

Rhodiola Fact Sheet from the National Center for Complementary and Integrative Health

1. Spasov AA, Wikman GK, Mandrikov VB et al. (2000) A double-blind, placebo-controlled pilot study of the stimulating and adaptogenic effect of Rhodiola rosea SHR-5 extract on the fatigue of students caused by stress during an examination period with a repeated low-dose regimen. Phytomedicine : international journal of phytotherapy and phytophqarmacology 7, 85-89.
2. Noreen EE, Buckley JG, Lewis SL et al. (2013) The effects of an acute dose of Rhodiola rosea on endurance exercise performance. Journal of strength and conditioning research / National Strength & Conditioning Association 27, 839-847.
3. Ishaque S, Shamseer L, Bukutu C et al. (2012) Rhodiola rosea for physical and mental fatigue: a systematic review. BMC complementary and alternative medicine 12, 70.
4. Shen B, Truong J, Helliwell R et al. (2013) An in vitro study of neuroprotective properties of traditional Chinese herbal medicines thought to promote healthy ageing and longevity. BMC complementary and alternative medicine 13, 373.
5. Bystritsky A, Kerwin L, Feusner JD (2008) A pilot study of Rhodiola rosea (Rhodax) for generalized anxiety disorder (GAD). Journal of alternative and complementary medicine 14, 175-180.
6. Darbinyan V, Aslanyan G, Amroyan E et al. (2007) Clinical trial of Rhodiola rosea L. extract SHR-5 in the treatment of mild to moderate depression. Nordic journal of psychiatry 61, 343-348.
7. Olsson EM, von Scheele B, Panossian AG (2009) 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 medica 75, 105-112.
8. Nabavi SF, Braidy N, Orhan IE et al. (2016) Rhodiola rosea L. and Alzheimer's Disease: From Farm to Pharmacy. Phytother Res 30, 532-539.
9. Punja S, Shamseer L, Olson K et al. (2014) Rhodiola rosea for mental and physical fatigue in nursing students: a randomized controlled trial. PloS one 9, e108416.