Panax ginseng is a plant used in traditional Chinese medicine (also known as Korean or Asian ginseng). Its root contains compounds called ginsenosides, which have antioxidative and anti-inflammatory effects. Panax ginseng is purported to enhance longevity, promote cognitive functions, and alleviate fatigue. Some clinical trials have reported that Panax ginseng treatment improves cognitive functions in healthy people and in dementia patients, but the evidence is mixed, and many others have shown a lack of benefit. Panax ginseng is generally safe when taken alone at recommended doses, but high doses or combining with other products may cause insomnia, rapid heartbeat, high blood pressure, and nervousness. Panax ginseng also interacts with many medications.
Panax ginseng has been tested in numerous randomized controlled trials, though the evidence remains inconclusive due to the inconsistencies in results and the lack of large, long-term, clinical trials. Our search identified:
There have been numerous clinical trials and observational studies on Panax ginseng supplementation. While some studies have reported benefit for cognitive functions [1; 2; 3; 4], many others have shown a lack of benefit [5; 6; 7; 8; 9; 10; 11], and overall there is a lack of high-level evidence that the benefits of Panax ginseng outweigh the risks. A meta-analysis of five double-blind randomized controlled trials in healthy subjects reported that Panax ginseng treatment for 8-12 weeks showed improvement in some aspects of cognitive function, behavior, and quality of life, though the evidence was not convincing or consistent across studies [12].
One of the included trials showed that ginseng treatment (200 mg/day) significantly improved working memory and mental arithmetic, but not attention or concentration [1], while a different study reported that ginseng treatment (400 mg/day) significantly improved attention but not memory [2]. In yet another study, ginseng treatment (400 mg/day) for 8-9 weeks improved selective reminding but not attention, concentration, or motor performance [3].
Most recently, a double-blind randomized controlled trial of 52 healthy individuals reported that Panax ginseng treatment (1 g/day) for eight weeks significantly increased the volume of a brain region important for memory and improved scores on executive function, attention, and memory, effects that were not seen in the placebo group [4].
In an observational study of 6,422 elderly people in South Korea, those who had higher lifetime cumulative ginseng intake (over five years) showed higher cognitive scores compared to those who never consumed ginseng, after controlling for factors such as age, sex, education, socioeconomic status, smoking, alcohol intake, cardiovascular disease, and APOE genotype [13]. But changes in cognitive function over four years of follow-up did not differ based on ginseng intake. As this study was an observational study, it was not designed to prove that ginseng intake is responsible for the higher cognitive functions.
Several randomized controlled trials have tested Panax ginseng in Alzheimer’s patients. In one systematic review that included two randomized controlled trials for ginseng, both trials showed that ginseng supplementation resulted in significant improvements in cognitive outcomes; however, due to the limitations in the methodological quality of the trials, results have not been conclusive [14]. In one study, patients with moderate-to-severe Alzheimer’s disease treated with 4.5 g/day of ginseng showed significant improvement in cognitive functions after 12 and 24 weeks of supplementation [15]. Similar results were reported in another study with the use of 4.5 and 9.0 g/day of Korean white ginseng in patients with mild-to-moderate Alzheimer’s disease [16]. However, improvements in cognitive functions disappeared 12 weeks after discontinuation of treatment.
The longest placebo-controlled clinical trial included 61 Alzheimer’s patients and lasted two years [17]. In the low-dose Panax ginseng group (4.5 g/day), cognitive scores (as measured by the Mini-Mental State Examination) improved after 48 weeks, then slightly decreased at 96 weeks. In the high-dose group (9.0 g/day), cognitive scores showed slight improvement at 48 and 96 weeks. In this study, maximum cognitive improvement was observed around 24 weeks, then sustained for two years.
Although some positive findings have been reported, further studies with more optimal methodological quality are necessary to evaluate the safety and efficacy of ginseng supplementation in individuals with Alzheimer’s disease and other dementias.
Multiple meta-analyses that included data from numerous randomized controlled clinical trials have reported that Panax ginseng is generally safe when taken alone, is not associated with serious adverse events, and incidences of adverse events are comparable to those of placebo groups [12; 18; 19; 20]. However, high doses of ginseng or taking ginseng with caffeine or other products may lead to insomnia, rapid heartbeat, high blood pressure, headaches, nervousness, and gastrointestinal issues. Panax ginseng interacts with many medications, including warfarin, aspirin, medications for depression, immunosuppressants, alcohol, and others [20; 21]. Ginseng affects blood sugar levels, and therefore may interact with anti-diabetics.
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.
Panax ginseng (Asian or Korean ginseng) is native to Korea, China, and Russia, and is the most commonly used and studied species of ginseng in herbal medicine. Other species of ginseng are also widely available, including Panax quinquefolius (American ginseng), Panax japonicus (Japanese ginseng), and Panax notoginseng (pseudoginseng).
Panax ginseng is available over the counter as whole root, liquid extract, capsule, and powder forms. Ginseng is often taken in doses of 200-400 mg/day, though doses vary based on the preparation. Clinical trials have often tested higher doses [11]. Panax ginseng often comes in either white or red ginseng forms. White ginseng is fresh ginseng that has been air-dried without being heated and is often used for long periods. Red ginseng is first steamed, then dried, and has a reddish color; due to its stimulating effects, it is typically used short-term [22]. Ginseng can also be consumed as soup (e.g., Samgye-tang, which is ginseng chicken soup), tea (Insam-cha, or ginseng tea), liquor (Insam-ju, or ginseng liquor), or in energy drinks.
More information on the safety and drug interactions for ginseng on Drugs.com
Full scientific report (PDF) on Cognitive Vitality Reports