Athletic success is dependent primarily upon genetic endowment with specific biomechanical, psychologic, and physiologic traits intrinsic to performance in a given competition, coupled with optimal training to maximize these trait potentials. Athletes who believe they have maximized the effects of training may resort to ergogenic aids to enhance performance. There is a growing inclination among athletes to use herbs to improve endurance performance or increase recovery after exercise. Ergogenic aids are believed to increase performance by some of the following mechanisms: renewing or increasing energy stores in the body, facilitating the biochemical reactions that yield energy, reducing or neutralizing performance-inhibiting metabolic byproducts, and facilitating recovery. The extent of validation for most herbs used for physical performance by athletes is based on tradition, identity of ingredients, advertisements, personal endorsements, use by other athletes, and the desire to succeed. In the United States, the Dietary Supplement Health Education Act of 1994 (DSHEA) defines dietary supplements as certain foods intended to supplement the diet that are not represented as conventional foods. Herbs or other botanicals and their extracts or concentrates are specifically mentioned as dietary supplements. The DSHEA allows claims of structure or function to be made for dietary supplement products but not foods. Claims are based on the manufacturer's interpretation of the incomplete scientific literature and are limited to effects of ingredients on the body's structure and function or on a person's health and well being . This poses a difficult decision for athletes and those involved in their training due to the extent of different supplements available. Even when choosing a specific supplement, the choices are numerous. This is especially true with ginseng.
There are various preparations and forms of ginseng, with different dosages and treatment lengths. Along with the multitude of products available containing ginseng, there are numerous studies addressing different forms, doses, and types of ginseng with varying results. Despite being one of the most widely used supplements and the most studied herb, ginseng still only has alleged ergogenicity. Athletes use and will continue to use ginseng as an ergogenic aid due to claims it increases fat utilization, decreases muscle glycogen utilization, and enhances endurance performance, despite lack of scientific verification. Also, many athletes take ginseng with the belief that these agents will attenuate immune and endocrine perturbation and thereby decrease the incidence of colds and infections and improve recovery . There are potential problems when taking ginseng supplements because of demonstrated differences in concentration of active ingredients found in ginseng preparations [3–5], and certain products do not even contain the ingredients indicated on the label . Although some types of ginseng have been shown to be possibly effective as treatments for diabetes, erectile dysfunction, and premature ejaculation [7••], a discussion of literature pertaining to theses effects is beyond the scope of this article. This article addresses the differences in available types of ginseng and reviews recent clinical findings, particularly regarding ginseng use in athletes.
The ginseng root is an ancient drug, having been used for several thousands of years as a tonic, prophylactic agent, and a “restorative.” It is one of the most often used nutritional supplements, ranging in price from $1 to nearly $200 dollars in an online price investigation. It has been used to treat a plethora of disorders ranging from anemia and chronic fatigue, to diabetes, heart disease, kidney disease, nervous disorders, wakefulness, shortness of breath and perspiration, forgetfulness, continuous thirst, lack of sexual desire, chronic and over-fatigue, dyspepsia, and nausea . Also, it has been suggested that ginseng has the ability to improve oxygen utilization, indicating an increase in fat utilization and subsequent sparing of carbohydrate stores . However, its efficacy has been established primarily through clinical experiences as opposed to scientific verification of pharmacologic effects. Nutritional analysis shows that 100 g of ginseng root contains 338 kcal, 12.2 g of protein, 70 g of carbohydrates, and measurable amounts of vitamins A, B1 (thiamine), B2 (riboflavin), B12, C, E, and niacin , as well as calcium, iron, and phosphorous . Ginseng preparations are extracted from the roots of various genera of the plant family Araliaceae and contain a wide variety of chemical substances, particularly glycosides, which are theorized to be ergogenic. Panax ginseng (PG), the root of the araliaceous plant, contains greater than 13 positively identified glycosylated steroidal saponins (ginsenosides) as the likely active agents. Standardized extracts used as supplements contain approximately 4% ginsenosides . Ginsenosides consist of a monosaccharide and one or more chemical moieties, and although their mechanism of action as a putative ergogenic aid is uncertain, they are believed to influence neurotransmitter concentrations in higher centers of the central nervous system, particularly the hypothalamus, so as to enhance both physical and mental capacity . Ginseng is thought to have a multitude of effects in the body, including effects on the production of corticotrophin and cortisol, immunomodulation, antioxidants and neuroendocrine activity, carbohydrate and lipid metabolism, and nitric oxidation production in the cardiovascular system . However, it is difficult to state the exact mechanism of action due to its large number of possible active ingredients. These theoretical effects are the likely rationale behind the use of ginseng by athletes.
Types of Ginseng
There are several known species of ginseng, including American, Chinese, Korean, and Japanese . Ginseng is available in many forms: whole root, root powder (white ginseng), steamed root powder (red ginseng), teas, tinctures, and standardized root extracts containing known and reproducible amounts of ginsenosides in every batch . It is also available as the ginseng substitute discovered in the late 1950s by a Russian research group. This new medical plant is known as Eleutherococcus senticosus (ES), but also goes by Siberian ginseng, ciwujia, eleuthero, eleuthero ginseng, Acanthopanax senticosus, touch-me-not, and devil's bush. Manufacturers claim it has the same effects as “true” types of ginseng [13,14]. “Ginseng” is the generic term given to all species of Panax (the plant genus) derived from the Araliaceous plant , a plant that is completely different from ES. The three most popular species of Panax currently recognized are Panax quinquefolius (American ginseng) (AG), Panax ginseng (PG) (Chinese/Korean ginseng), and Panax japonicus (Japanese ginseng) [16•]. ES and Panax species are derived from different plants but both are from the same plant family (Araliaceae). Eleutherosides (from the root) and cixujianosides (from the leaf) are thought to be responsible for the effects of ES, similar to the ginsenosides in Panax species . In a study by Baranov , the reported difference in ES from true ginseng was demonstrated by showing ES had fewer side effects than PG, did not produce excitation in patients, had a more universal effect on general immunity of an organism, and less variation in efficacy with seasonal harvests.
Eleutherococcus senticosus (Siberian ginseng)
There have been a multitude of studies done addressing the efficacy of Siberian ginseng (ES) as an ergogenic aid. Original studies of ES revealed contradictory results when evaluating its effects on athletic performance. Initially ES was reported to lower recovery rates, improve exercise performance, and increase fat utilization. In contrast, several recent studies reported no effect of ES supplementation on endurance training [18–20]. One of the first studies that generated a great deal of interest in Siberian ginseng use in athletes in 1996 was done by Wu et al. . It was a placebo-controlled protocol with progressive resistance training every 3 minutes for 18 minutes with ES supplementation of 800 mg in 16 healthy males from 25 to 35 years of age. The data showed a significant decrease in recovery rate, more rapid recovery of HR, and a dramatic 43% increase in fat utilization. However, subjects served as their own controls in pre-post comparison, which could have given rise to a training bias, and the study was based on an extremely small sample size. A follow-up study done by Campbell et al.  found similar results in incremental cycling to exhaustion of 10 healthy 25- to 35-year-olds. However, this study also had a number of design flaws, including a training bias, no control for variables, and a limited sample size. The initial study in 1986 by Asano et al.  had similar results and design flaws. It included six male baseball players in a single-blind placebo-controlled study of supplementation for 8 days of ES, 300 mg. They were exercised to exhaustion in three consecutive cycling tests over 3 days with an increase in cycling time to exhaustion and total work capacity noted. This study design allowed for a training bias and had no crossover design. A final proponent for the use of ES supplementation was done by Szolomicki et al.  in Poland. The study tested 31 subjects to exhaustion after a 30-day period of 25 drops of ES three times a day. Again, a significant improvement in VO2max and maximal minute ventilation was noted. However, interpretation of these results is difficult due to lack of placebo control and no standardization of dosing . The above-mentioned studies are the foundation for the ergogenic potential of ES, but each study has significant flaws. These earlier positive results led to more recent, stringent investigations of the use of ES as an ergogenic aid.
Investigations of supplementation with ES published in peer-reviewed exercise and nutrition oriented journals followed more robust protocols. The results of these studies were contradictory to the early studies of Siberian ginseng. In a randomized double-blind placebo-controlled crossover study, Eshbach et al.  supplemented 10 male athletes with 1200 mg/d of ES versus placebo. Each subject completed two experimental trials of a 2-hour ride followed by a 10-km time trial before and after supplementation. The results showed no improvement in recovery rate or time trial with ES. Although improved in design, the study was still done with a small number of participants. McNaughton et al.  also evaluated the effect of ES and PG on endurance training and strength. Thirty trained runners were randomly assigned to either ES, 1000 mg, PG, or placebo for 6 weeks and tested. The results showed ES did not improve VO2max or heart rate recovery. Also, PG showed no change in VO2max, but a significant increase in pectoral and quadriceps strength was noted . In a study by Dowling et al. , 20 trained distance runners were evaluated in a randomized double-blind placebo-controlled study to determine the efficacy of ES. Subjects were supplemented for a 6-week period and tested in a 10-minute run at their 10-km pace. The research team found no difference between the groups for any of the variables studied in the trained runners. Cheuvront et al.  used a double-blind crossover study to determine the ergogenic effects of ES supplementation on recreational cyclists. Ten healthy men were randomly assigned to either ES, 800 mg or placebo for 7 days then performed 30- and 10-minute cycling tests. None of the results differed between treatments indicating that during exercise conducted at low intensity, ES does not improve recovery or endurance in recreational athletes. The results produced by more controlled studies do not seem to indicate the use of ES is advantageous in endurance athletes. However, the lack of uniformity across testing protocols, supplementation, and duration make it difficult to arrive at concrete conclusions.
Panax ginseng (Chinese ginseng)
PG has also been studied in a variety of roles, including its use in endurance athletes. As noted previously, in the study by McNaughton et al. , PG showed no improvement in recovery, but had a significant impact on pectoral and quadriceps strength. In another evaluation of PG, Williams  conducted a double-blind placebo-controlled crossover study to investigate the effect of a PG preparation during a Bruce treadmill protocol. It was noted to significantly increase VO2max and total workload, and decrease heart rate during the workouts. The findings were attributed to the total preparation, not ginseng alone, but the authors concluded ginseng was most likely to have been the key ingredient. However, recommendations can not be made based on these conclusions and further studies would be necessary to confirm these results.
A supplement called Panax notoginseng (PNG), which is similar but not identical to PG, was recently evaluated in a randomized double-blind placebo-controlled trial as an endurance aid during exercise. Liang et al.  set out to investigate whether a single dose of 1350 mg/d PNG supplement for a duration of 30 days would have an effect on aerobic capacity, endurance, blood pressure, and skin blood flow in adults 20 to 35 years old. The authors conclude that PNG was effective for enhancing aerobic capacity and endurance, and lowering mean arterial and diastolic blood pressure. The results are intriguing because larger doses and longer supplementation were performed in this investigation. However, the study does not account for two subjects from 8 minutes of exercise until exhaustion in the experimental group and the VO2max in the experimental group was significantly higher pretrial possibly allowing for larger post-test improvement. Also, the decrease in mean arterial blood pressure was only significant at exhaustion. This study, like many others, raises questions that need to be addressed in further clinical trials of each type of ginseng. Currently, the use of PNG for improved endurance in athletes cannot be endorsed.
It has been reported that ginseng influences the nervous system. This has led to studies proposing improved psychomotor performance during physical exercise with PG. Ziemba et al.  reported a significant decrease in reaction time in response to auditory and visual stimuli, accompanied by an increase in subjective feelings of vitality, improved concentration, work output, and mood after ginseng treatment in men and women of different ages. Furthermore, in a double-blind placebo-controlled study of 15 male soccer players, participants were treated with 350 mg/d for 6 weeks, followed by an incremental graded exercise test to volitional exhaustion and reaction time measurements. According to the authors, PG showed a beneficial effect on mental alertness and coordination of movements. PG was used again in a double-blind placebo-controlled balanced crossover study of 30 healthy young adults to assess its effect on mental acuity. Subjects performed a 10-minute battery test, then were given 200 mg or 400 mg of PG or placebo and retested 60 minutes later. Participants improved serial sevens and significantly reduced subjective mental fatigue throughout the battery, most notably those receiving 200 mg every day. From their investigation, Reay et al.  suggested an improved performance and subjective feelings of mental fatigue during sustained mental activity occurred possibly due to the glucoregulatory properties of PG. The results of these studies are interesting as possible areas for future investigations but it is still not known if these effects translate into on field benefits or improved athletic performance.
Panax quinquefolius (American ginseng)
AG has been thought to have the same benefits as other ginseng preparations. A randomized double-blind placebo-controlled crossover study of 13 male athletes was designed to investigate whether AG improved endurance exercise performance. Thirteen physically active male college students were given 400 mg of ginseng or placebo for 4 weeks. They were then tested by a Bruce protocol treadmill study . This study did not demonstrate any improvement in performance or endurance training. A recent randomized double-blind placebo-controlled study of AG addressed the potential to modulate the immune response as an alternative use of the supplement. The study set out to examine the efficacy of AG in preventing colds. In Edmonton, Canada, 323 participants, 18 to 65 years of age, were given ginseng or placebo at the onset of flu season and followed. The mean number of colds per person was significantly lower in the ginseng group. Also, the severity of symptoms and the number of days symptoms were experienced decreased significantly [27••]. This effect of AG is not in itself ergogenic, but if it prevents or decreases cold or flu symptoms in athletes, it may allow for improved performance.
Adverse Effects and Safety
In much of the literature, ginseng has been reported to be medically safe; however, there are possible side effects from its ingestion. These effects include stomach irritation, diarrhea, and insomnia [16,17]. There has been no teratogenicity or mutagenicity reported , but caution should be taken with ginseng use in pregnant or nursing women along with individuals with uncontrolled high blood pressure or those taking hormonal drugs due to inadequate data. Siegel  used a questionnaire based system to identify side effects secondary to long-term (2 years) PG or ES use of unspecified doses. The side effects included diarrhea (35%), skin eruptions (25%), sleeplessness (20%), nervousness (19%), and hypertension (17%). It was noted that with only 12 weeks of supplementation, the side effects were similar, but predominantly in subjects who also used psychomotor stimulants such as caffeine. The use of ginseng is not banned by the International Olympic Committee (IOC) . However, it is important to note that the IOC reported in a recent press release that a sanctioned laboratory tested 634 random sport supplements and found that 94 (14.8%) contained substances that have been banned or restricted by the IOC and the World Anti-Doping Agency . The presence of banned substances in these products is a potential route for the generation of a positive urinalysis test. In addition, a urinalysis test may be positive if ingestion of nutritional supplements results in the production of banned substances in the body. To disprove this theory with a specific ginseng preparation, forty recreational athletes participated in a double-blind placebo-controlled phase II clinical trial for 28 days ingesting 400 mg of AG every day equivalent to the content of the product Cold-FX (CV Technologies, Edmonton, Alberta, Canada). The intended use of Cold-FX is to prevent symptoms of cold and flu from disturbing an athlete's training program. Using IOC drug testing protocol, none of the subjects had a positive test result for any banned substances . Ginseng likely interacts with multiple medications including monoamine oxidase inhibitor medications, coumadin, furosemide, immunosuppressants, and cytochrome P450 substrates [1,7••]. Also, ginseng may lower blood glucose, theoretically, causing hypoglycemia with concomitant use with antidiabetic medications [7••]. As with any supplement, athletes should be cautious and educated about including ginseng in their training regimen.
For multiple reasons, it is difficult to arrive at positive conclusions regarding ergogenic effects of ginseng supplementation. First, there are multiple different types of ginseng containing many different active compounds. Second, products contain varying amounts of these active compounds, and there seems to be no standardization of dosing. Furthermore, most studies have not been reproducible and yielded varying results. Although ginseng is one of the most often studied ergogenic aids, there are still a multitude of considerations to guide future research. Areas of interest for future research appear to be in the prevention of viral upper respiratory illnesses with AG, augmentation of cognitive function and concentration, and strength improvement with PG, and endurance training with PNG. Although relatively safe, the use of ginsengs cannot be encouraged for their direct effects on endurance training or athletic performance until more information is obtained.
References and Recommended Reading
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
1. Bucci LR: Selected herbals and human exercise performance.Am J Clin Nutr
2. Gaffney BT, Hugel H, Rich P: The effects of Eleutherococcus senticosus and Panax ginseng on steroidal hormone indices of stress and lymphocyte subset numbers in endurance athletes.Life Sci
3. Cheuvront SN, Moffatt RJ, Biggerstaff KD, et al.
: Effect of ENDUROX on metabolic responses to submaximal exercise.Int J Sport Nutr
5. Harkey MR, Henderson GL, Gershwin ME, et al.
: Variability in commercial ginseng products: an analysis of 25 preparations.Am J Clin Nutr
6. Walker AF: What is in ginseng?Lancet
7.•• Natural Databases Comprehensive Databases.
Available at: http://www.naturaldatabase.com
. Accessed June 9, 2006.
A comprehensive database that provides objective, evidence-based, clinical information about many ingredients and brand name products in natural medicine.
8. Bahrke MS, Morgan WP: Evaluation of the ergogenic properties of ginseng.Sports Med
9. Barna P: Food or drug? The case of ginseng.Lancet
10. Ziemba AW, Chmura J, Kaciuba-Uscilko H, et al.
: Ginseng treatment improves psychomotor performance at rest and during graded exercise in young athletes.Int J Sport Nutr
11. Williams MH: Nutritional ergogenics in athletics.J Sports Sci
12. Hsu CC, Ho MC, Lin LC, et al.
: American ginseng supplementation attenuates creatine kinase level induced by submaximal exercise in human beings.World J Gastroenterol
13. Baranov AI: Medicinal uses of ginseng and related plants of the Soviet Union: recent trends in the Soviet literature.J Ethnopharmacol
14. Eleutherococcus senticosus- a new medicinal herb of the araliaceae family. In Pharmacology of Oriental Plants. Edited by Che KK, Mukerji B, Volicer L. New York: Macmillan; 1965:97–103.
15. Bahrke MS, Morgan WP: Evaluation of the ergogenic properties of ginseng.Sports Med
16.• Goulet EDB, Dionne IJ: Assessment of the effects of Eleutherococcus senticosus on endurance performance.Int J Sports Nutr Exerc Metab
Recent review article that takes an evidence-based approach to the ergogenic potential of ginseng. This is a valuable reference for any provider looking for additional information about Siberian ginseng as an ergogenic aid for endurance athletes.
17. Tang W, Eisenbrand G: Chinese Drugs of Plant Origin: Chemistry, Pharmacology, and Use in Traditional and Modern Medicine. New York: Springer-Verlag; 1992.
18. Asano K, Takahashi T, Miyashita M, et al.
: Effect of Eleutherococcus senticosus extract on human physical working capacity.Planta Med
19. Campbell TC, et al.
: Effects of Radix Acanthopanax senticosus (ciwujia) on exercise.J Strength Cond Res
20. Wu YN, Wang XQ, Zhao YF, et al.
: Effect of Ciwujia (Radix acanthopanacis senticosus) preparation on human stamina.J Hyg Res
21. Szolomicki J, Samochowiec L, Wojcicki J, Drozdzik M: The influence of active components of Eleutherococcus senticosus on cellular defense and physical fitness in man.Phytother Res
22. Eschbach LC, Webster MJ, Boyd JC, et al.
: The effect of Siberian ginseng (Eleutherococcus senticosus) on substrate utilization and performance during prolonged cycling.Int J Sports Nutr Exerc Metab
23. McNaughton L, Egan G, Caelli G: A comparison of Chinese and Russian ginseng as ergogenic aids to improve various facets of physical fitness.Int Clin Nutr Rev
24. Dowling EA, Redondo DR, Branch JD, et al.
: Effect of Eleutherococcus senticosus on submaximal and maximal exercise performance.Med Sci Sports Exerc
25. Liang MT, Podolka TD, Chuang WJ: Panax Notoginseng enhances physical performance during endurance exercise.J Strength Cond Res
26. Reay JL, Kennedy DO, Scholey AB: Single doses of Panax ginseng reduce blood glucose levels and improve cognitive performance during sustained mental activity.J Psychopharmacol
27.•• Predy GN, Goel V, Lovlin R, et al.
: Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial.Can Med Assoc J
Study that used a stringent protocol to evaluate the use of American ginseng to minimize infections during cold and flu season. The authors found significant improvements with supplementation versus placebo.
28. Siegel RK: Ginseng abuse syndrome: problems with the panacea.JAMA
29. Goel DP, Geiger JD, Shan JJ, et al.
: Doping control urinalysis of a ginseng extract, cold-FX, in athletes.Int J Sport Nutr Exerc Metab