An objective review of the mechanisms by which E. Longifolia acts to raise testosterone
Natural Therapies: Herbology & Detoxification: NUTR06102
Robert T. Davidson, PhD
August 6, 2017
For years Malaysian Ginseng (Eurycoma Longifolia) has been prescribed as an alternative medicine to raise testosterone levels and aid in erectile dysfunction naturally; however, the scientific research is a bit contradictory. Although there are some enhancements to testosterone, the direct impact of Eurycoma Longifolia on T levels is not entirely understood. My observation of various studies and the literature on Eurycoma Longifolia suggest that increases in testosterone and libido are an indirect result that comes from a lowering of anxiety and stress. Lower stress levels result in lower cortisol; and lower cortisol results in a lift in testosterone production. In turn, this would also cause better blood flow for erections. There is also research that shows Eurycoma Longifolia has natural estrogenic blocking properties. Therefore, when you combine Eurycoma Longifolia stress relieving and estrogenic blocking properties we have a recipe elevated testosterone levels; but only on a relative scale. Research is divided on Malaysian ginseng’s impact on testosterone; however, there are many secondary mechanisms by Malaysian Ginseng can undoubtedly affect libido and testosterone levels; as we know libido, hormone levels and stress are closely related. We will explore the research and alternative mechanisms in the pages below.
The reason Malaysian Ginseng (Eurycoma Longifolia) is considered a testosterone enhancer is, the CYP17 enzyme found in the male testes causes the activation of the CYP17 enzyme to increase the conversion of pregnenolone precursors into dehydroepiandrosterone (DHT). It is believed that Malaysian Ginseng acts on the CPY17 enzyme to upregulate the pregnenolone to DHT conversion process. In the results of a study by Wahab NA, et al. they study the effects of Eurycoma Longifolia Jack on Spermatogenesis in estrogen-treated rats, suggests that Eurycoma Longifolia can increase sperm count and initiate spermatogenesis via estrogen suppression . To further support this notion another study by Chan KL, et al. on The effect of Eurycoma Longifolia on sperm quality of male rats shows accumulation of Eurycomanone in the testes of rats who have been given chronic administration of Eurycoma Longifolia; suggesting that Eurycoma Longifolia does make its way into the testes
The evidence suggests Eurycoma Longifolia increases testosterone levels in hypogonadal rats. However, there are is no research supporting this same effect in otherwise healthy rats who showed no sign of hypogonadism. In a four year study by Tambi MI et al in 2012 which followed 320 men with serum testosterone levels below 6umol/L, they discovered that 200mg of Eurycoma Longifolia was quite effective at increasing patient’s libido and elevating serum testosterone levels. Patient’s saw an increase in testosterone levels from 5.66 +/-1.51 umol/L to 8.31+/-2.41 umol/L which was a 46% increase in one year.  This could be because the rats have a high estrogen problem and the estrogen blocking capabilities of the Malaysian Ginseng are significant enough to show an increase in the testosterone. But on a relative scale in non-hypogonadal male rats, the increase is insignificant, perhaps because androgen receptors are utilized fully. The question is whether or not serum testosterone is rising or estrogen is blocked therefore increasing testosterone on a relative scale. On the contrary, in an alternative study on humans, researchers examined the effects of Eurycoma Longifolia Jack extract in human males. Testing in humans over rats is important because we are investigating the efficacy of EL in humans, not rats. Although rats are thought of as a great parallel, it is not exact. The results of the test showed Prolonged ElJ supplementation i.e. Physta® at 400 mg/day for six weeks did not affect urinary Testosterone: Epitestosterone ratio. More significant to the research article is the fact that unlike normal testosterone enhancing drugs Eurycoma Longifolia has no impact on urine levels of testosterone. Future studies with a higher dosage and longer supplementation period are still warranted to ensure that ElJ does not affect urinary testosterone levels; this would also provide more clarity on if a certain amount and time are necessary for results. 
Abdul Shukor Tajul Ariff et al studied the Effects of Eurycoma longifolia on Testosterone Level and Bone Structure in an Aged Orchidectomised Rat Model. The results showed that 15mg/kg (equivalent 100mg oral dose in humans) of concentrated Eurycoma did not raise testosterone over a period of 6 weeks in otherwise normal rats. However, it appears that the effective dosage in humans lies between 200-800mg/kg according to a study that analyzed Eurycoma longifolia jack on leavator ani muscle. After studying castrated and un-castrated rats over the course of 12 weeks, the results showed a significant increase in the leavator ani muscle indicating the pro androgenic effects of Eurycoma Longifolia; however, they failed to measure serum testosterone levels. Therefore, it’s unclear as to whether the effect was primary or secondary.
Some of the secondary documented benefits are used as an aphrodisiac, an erection enhancer and anxiety and stress reliever. As an aphrodisiac, the data support an improvement in desire and libido. An animal study called, Influence of Eurycoma Longifolia on the copulatory activity of sexually sluggish and impotent male rats, which used sexually sluggish male rats, administered a 500 mg/kg dose over 6-12 days with some positive results. There was some modest improvement in the delay of ejaculation and a 25% lift in sexual frequency.  Another study tested a 300mg dose in human males and showed 8.4-10.8% increase in libido  Along with the aphrodisiac properties of Eurycoma Longifolia is a rise in the frequency or intensity of erections. Most notable was a study performed with rats showed an increase in the size of the levator ani muscle of the pelvis from a 13.2-23.4%, indicating some androgenic effect. Lastly, in a study on the anxiolytic activity of Eurycoma Longifolia in rats, extracts were injected into subjects at varying doses while measuring anxiety level. The results of the study showed that Eurycoma Longifolia is only slightly less efficient than the pharmaceutical drug Diazepam. Eurycoma Longifolia reduced anxiety by 31.2-36.3% compared to 25.9% reduction in the control group who was given 1mg/kg of Diazepam. The same study went on to further their finding by testing Eurycoma Longifolia ability to reduce fighting among inbred rats, and the results were once again congruent with the previous findings. Eurycoma Longifolia cut fighting by 5.3-6.2 episodes; which was just slightly weaker than diazepam group.  In an alternative study in humans the stress hormones and mood state in 63 subjects (32 men and 31 women) were screened for moderate stress and supplemented with a standardized hot-water extract of Tongkat Ali root (TA), another name for Malaysian Ginseng, for four weeks. Analysis of variance (ANOVA) with significance set at p < 0.05 was used to determine differences between groups. The results showed tension reduced by 11%, anger reduced by 12%, and confusion reduced 15%. Also stress hormone profile (salivary cortisol and testosterone) significantly improved by Malaysian Ginseng supplementation, which showed a reduction in cortisol exposure by 16% and increased testosterone status 37% 
In conclusion, the effects of Eurycoma Longifolia on serum testosterone levels appear to be inconclusive; it is apparent that there is some impact on testosterone; however, it is unclear whether this is a direct increase in serum testosterone or acting on the secondary mechanism to induce such results. It appears that Eurycoma Longifolia is best used as an anti-anxiety and stress reliever; as the studies are evident. Eurycoma Longifolia reduces anxiety and stress, and the results of less stress are more energy and an increase in libido; which is most likely why Malaysian Ginseng is prescribed as a natural testosterone enhancer. In reality, libido is not entirely linked to testosterone levels and more closely related to stress levels, fatigue, body fat and sleep. Therefore Malaysian Ginseng is excellent at decreasing the body’s stress levels and in turn increases libido; in turn potentially increasing testosterone production.
1 . Wahab NA, et al. (2010) The effect of eurycoma longifolia Jack on spermatogenesis in estrogen-treated rats. Retrieved From: http://www.ncbi.nlm.nih.gov/pubmed/20126351
In this study adult male rats weighing 200-250 g were divided into four groups of six rats each. Group A (control) was given solvent in the same manner as the treated groups were given EL. Group B was treated with EL (8 mg/kg body weight) orally. Group C was treated with estradiol (E(2)) (intramuscular dose of 500 microg/kg body weight), and group D received a combined treatment of oral EL and intramuscular E(2). After fourteen consecutive days of treatment, rats from all groups were sacrificed and subjected to spermatogenic and epididymal sperm cell counts.This study is significant because it shows how Eurycoma Longifolia extract acts as a potential agent for reversing the effects of estrogen by increasing spermatogenesis and sperm counts in rats after fourteen consecutive days of treatment. This study is important because it is trying to determine a mechanism by which EL raises serum testosterone rather than the result.
2. Chan KL, et al. (2009) The effect of Eurycoma longifolia on sperm quality of male rats. Nat Prod Commun. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/19911566
This study was significant for two reasons, Testosterone level was significantly higher in the testes (p after 30 days of oral treatment with the standardized MeOH extract. Secondly eurycomanone was detected in the rat testis homogenates by HPLC-UV and confirmed by LC/MS, and may have contributed towards the improvement of sperm quality. Thus, the plant may potentially be suitable for the management of male infertility.
3. Tambi MI et all (2011) Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/21671978
This study was important for review because showed some positive benefits for overcoming the symptoms of late onset hypogonadism. As well it is one of the few that measured serum testosterone and showed positive increase. This study was positive for the imact of E. Longifolia on serum testosterone.
4. Abdul Shukor Tajul Ariff et al (2012) Effects of Eurycoma longifolia on Testosterone Level and Bone Structure in an Aged Orchidectomised Rat Model. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433727/
This study compared the effects of Eurycoma Longiflia on testosterone in neutered rats versus normal rats in order to exam the lift in testosterone and bone density. EL failed to emulate the testosterone replacement ability to raise the testosterone level and restore the bone structure of orchidectomized rats. It also failed to produce any effect when supplemented to normal male rats. The results of this study were potentially detrimental EL’s prescription for low testosterone. However, the study does leave some room for further studies on androgen-deficient rats who still have their testes intact. In the review of E. Longifolia it is important because it negates the impact on testosterone.
5. Ang HH et all (2001) Effects of Eurycoma longifolia jack on levator ani muscle in both uncastrated and testosterone-stimulated castrated intact male rats Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/11693547
This study is important because it clarifies the dosage necessary in order to drive optimal results. The study analyzes dosgaes of 200, 400 and 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack and its impact on laevator ani muscle in both uncastrated and testosterone-stimulated castrated intact male rats after dosing them for 12 consecutive weeks. The results showed showed that 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack significantly increased (p<0.05) the leavator ani muscle to 58.56+/-1.22, 58.23+/-0.31, 60.21 +/-0.86 and 62.35 +/-0.98 mg/100 g body weight, respectively, when compared with the control (untreated) in the uncastrated intact male rats and 49.23+/-0.82, 52.23+/-0.36, 50.21+/-0.66 and 52.35+/-0.58 mg/100 ence, the pro-androgenic effect as shown by this study further supported the traditional use of this plant as an aphrodisiac.
6.Zanoli P, et al. (2009) Influence of Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/19703544
This study evaluated the influence of Eurycoma longifolia Jack on sexual behavior (including both motivation and copulatory performance) of sexually sluggish and impotent male rats. Groups of 8 animals each were submitted to three different types of treatment: (1) acute at 3 dose levels (250, 500 and 1000 mg/kg); (2) subacute (daily for 6 days) at the dose of 500 mg/kg and (3) subchronic (daily for 12 days) at the same dose (500 mg/kg). The results showed Eurycoma longifolia root improved sexual performance but not motivation in sluggish rats after acute or subacute administration. The effect could be mainly ascribed to increased testosterone levels. The results of this study show a positive boost to testosterone and to mood which could be a byproduct of reduced anxiety or a relative lift in testosterone.
7. Ismail SB, et al. (2012) Randomized Clinical Trial on the Use of PHYSTA Freeze-Dried Water Extract of Eurycoma longifolia for the Improvement of Quality of Life and Sexual Well-Being in Men. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/23243445
In this study the researchers explore Eurycoma longifolia as an aphrodisiac and remedy for decreased male libido. Sperm motility is associated with libido and therefore used as a reference point when examining the benefits of a supplement to boost libido. The 12-week study of 109 men between 30 and 55 years of age consisted of either treatment of 300 mg of water extract of E. longifolia (Physta) or placebo. The EL group showed higher scores in the overall Erectile Function domain in IIEF (P < 0.001), sexual libido (14% by week 12), SFA- with sperm motility at 44.4%, and semen volume at 18.2% at the end of treatment. Compared to the placebo group
8. Ang HH et al. (1999). Studies on the anxiolytic activity of Eurycoma longifolia Jack roots in mice. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/10361892
This study examined the anti-anxiety effects of Eurycoma Longifolia Jack roots. E. longifolia Jack extract produced a significant increase in the number of squares crossed (controls= 118.2 +/- 10.2 squares), but significantly decreased both the immobility (controls = 39.4+/- 4.0 sec) and fecal pellets (controls= 12.3 +/-2.1 fecal pellets) when compared with control mice in the open-field test; they significantly increased the number of entries (controls=6.7+/-0.5 entries) and time spent (controls=42.9+/-0.1 sec) in the open arms, but decreased both the number of entries (controls= 13.2+/-0.7 entries) and time spent (controls= 193.4+/-0.7 sec) when compared with the control mice in the closed arms of the elevated plus-maze test. Furthermore, fractions of E. longifolia Jack extract decreased the fighting episodes significantly (controls= 18.0+/-0.4 fighting episodes) when compared with control mice. In addition, these results were found to be consistent with anxiolytic effect produced by diazepam. Hence, this study supports the medicinal use of this plant for anxiety therapy.
9. Chee Keong Chen et al (2014) Supplementation of Eurycoma longifolia Jack Extract for 6 Weeks Does Not Affect Urinary Testosterone: Epitestosterone Ratio, Liver and Renal Functions in Male Recreational Athletes
Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4085925/
In this study the researchers examine the effects of Eurycoma longifolia Jack Extract in humans (males). Testing in humans over rats is important because we are examining the efficacy of EL in humans not rats. Although rats are commonly thought of as a great parallel it is not exact. The results of the test showed Prolonged ElJ supplementation i.e. Physta® at 400 mg/day for 6 weeks did not affect urinary Testosterone :Epitestosterone ratio and hence will not breach doping policies of the International Olympic Committee for exogenous testosterone or precursor administration. More significant to the research article is the fact that unlike normal testosterone enhancing drugs EL has no impact on urine levels of T:E. Future studies with a higher dosage and longer supplementation period are still warranted to ensure that ElJ does not pose any doping issue or compromise the safety of the individuals consuming them; this would also provide more clarity on if a certain amount and time is necessary for results.
10. Shawn M Talbott et al ( 2013)Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3669033/
This study examines Eurycoma longifolia, a medicinal plant commonly called tongkat ali (TA) and “Malaysian ginseng.” TA roots are a traditional “anti-aging” remedy and modern supplements are intended to improve libido, energy, sports performance and weight loss. Previous studies have shown properly-standardized TA to stimulate release of free testosterone, improve sex drive, reduce fatigue, and improve well-being. This study was significant because it eludes to the fact that there are several studies showing EL to raise Testosterone levels; none of which I have found. Significant improvements were found in the TA group for Tension (−11%), Anger (−12%), and Confusion (−15%). Stress hormone profile (salivary cortisol and testosterone) was significantly improved by TA supplementation, with reduced cortisol exposure (−16%) and increased testosterone status (+37%). Libido and hormone levels are greatly impact by stress, sleep and cortisol. Therefore, the missing link to ELs benefit could be in cortisol control. In conclusion, tongkat ali, used for centuries in traditional medicine systems of Southeast Asia for treating lethargy, low libido, depression, and fatigue, appears to have significant potential for restoring hormone balance (cortisol/testosterone) and improving psychological mood state in humans exposed to various modern stressors, including aging, dieting, and exercise stress.