The following medical research studies document the benefits of Tongkat ali in helping erectile dysfunction and impotence problems. These health studies are published on the website http://www.ncbi.nlm.nih.gov of the National Library of Medicine, National Institutes of Health, U.S. Public Health Service.  

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Tongkat Ali Review by Dr. Simon Chua,

Department of Pharmaceutical Sciences,
Wayne State University, USA

In a preliminary study at the Reproductive Research Center in Kuala Lumpur, Malaysia, 30 married men, aged 31-52 years old, took Tongkat Ali regularly for three consecutive weeks. Interviews indicated that 48% felt healthy, active and energized, and 40% felt increased sexual desire. The subjects showed an increased free testosterone index. Increased testosterone levels help improve libido, energy and muscle mass for body building. Their levels of DHEA, another critical steroid hormone, gradually increased from 26% after one week to 47% after three weeks. Most subjects demonstrated increased satisfaction in their sexual health and performance. In addition, animal studies have shown that Tongkat Ali may increase testosterone availability as well as libido in mice (Source: Article from the book Molecular Biology of the Cell,  published on Sept. 1, 2002)

Effects of Eurycoma longifolia Jack (Tongkat Ali) on the initiation of sexual performance of inexperienced castrated male rats.

Ang HH, Cheang HS, Yusof AP.

School of Pharmaceutical Sciences, University Science Malaysia, Penang, Malaysia, as reported in Exp Anim. 2000 Jan;49(1):35-8.

We studied the effects of Eurycoma longifolia Jack, commonly known as Tongkat Ali in Malaysia, on the initiation of sexual performance and the weights of sexual accessories in inexperienced castrated male rats. The doses of 200, 400 and 800 mg/kg body weight, which were extracted from E. longifolia Jack, were orally administered to the rats twice daily for 10 days prior to the tests and continued throughout the test period. Testosterone was used as a positive control after injecting 15 mg/kg daily subcutaneously for 32 days. Results showed that E. longifolia Jack produced a dose-dependent increase in sexual performance of the treated animals, but the E. longifolia Jack groups showed lower sexual performance in mounting, intromission and ejaculation than the testosterone group. Further results also showed that E. longifolia Jack promoted the growth of both ventral prostate and seminal vesicles as compared with the control, but the growth of sexual accessories at 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack was less than that of testosterone treated group. The present study therefore gives further evidence of the folkuse of E. longifolia as an aphrodisiac.

PMID: 10803359 [PubMed - indexed for MEDLINE]

Evaluation of the potency activity of aphrodisiac in Eurycoma longifolia Jack.

·        Ang HH,

·        Ikeda S,

·        Gan EK.

School of Pharmaceutical Sciences, University Science Malaysia, Minden, 11800, Penang, Malaysia. hhang@usm.my, as reported in Phytother Res. 2001 Aug;15(5):435-6.

The butanol, methanol, water and chloroform extracts of the roots of Eurycoma longifolia Jack were studied using various tests of potency of treated male rats. The results showed that E. longifolia produced a dose-dependent, recurrent and significant increase in the episodes of penile reflexes as evidenced by increases in quick flips, long flips and erections of the treated male rats during the 30 min observation period. These results provide further evidence that E. longifolia increases the aphrodisiac potency activity in treated animals. Copyright 2001 John Wiley & Sons, Ltd.

PMID: 11507738 [PubMed - indexed for MEDLINE]

Eurycoma longifolia Jack enhances libido in sexually experienced male rats.

·        Ang HH,

·        Sim MK.

School of Pharmaceutical Sciences, University of Science Malaysia, Penang, Malaysia, as reported
in Exp Anim. 1997 Oct;46(4):287-90.

The effects of Eurycoma longifolia Jack were studied on the libido of sexually experienced male rats after dosing them with 200, 400 and 800 mg/kg body weight twice daily of different fractions of E. longifolia Jack for 10 days. Results showed that E. longifolia Jack produced a dose-dependent increase in mounting frequency of the treated animals with 400 mg/kg of chloroform, methanol, water and butanol fractions resulting in mounting frequencies of 5.3 +/- 1.2, 4.9 +/- 0.7, 4.8 +/- 0.7 and 5.2 +/- 0.1, and 800 mg/kg further increased them to 5.4 +/- 0.8, 5.4 +/- 0.8, 5.2 +/- 0.6 and 5.3 +/- 0.2 respectively but there were no erections, intromissions, ejaculations or seminal emissions during the 20-min observation period which allowed for the measurement of sexual arousal reflected by mounting frequency uninfluenced by other behavioural components. This study provides evidence that E. longifolia Jack is a potent stimulator of sexual arousal in sexually vigorous male rats in the absence of feedback from genital sensation.

PMID: 9353636 [PubMed - indexed for MEDLINE]

Effects of Eurycoma longifolia Jack on sexual qualities in middle aged male rats.

·        Ang HH,

·        Ngai TH,

·        Tan TH.

School of Pharmaceutical Sciences, University Science Malaysia, Minden, Penang, Malaysia. hhang@usm.my, as reported in Phytomedicine. 2003;10(6-7):590-3.

The effects of Eurycoma longifolia Jack were studied on the sexual qualities of middle aged male rats after dosing them with 0.5 g/kg of various fractions of E. longifolia whilst the control group received 3 ml/kg of normal saline daily for 12 weeks. Results showed than E. longifolia Jack enhanced the sexual qualities of the middle aged male rats by decreasing their hesitation time as compared to controls with various fractions of E. longifolia Jack produced 865-916 (91-96), 860-914 (92-98), 850-904 (93-99), 854-890 (95-99), 844-880 (94-98), 840-875 (94-98), 830-870 (94-98), 825-860 (94-98), 820-850 (96-99), 800-840 (93-98), 750-795 (94-99) and 650-754 sec (82-95%) in contrast to controls which produced 950 (100), 934 (100), 910 (100), 900 (100), 895 (100), 890 (100), 885 (100), 880 (100), 855 (100), 860 (100), 800 (100) and 790 sec (100%) throughout the investigation period. Besides these, there was a transient increase in the % of the male rats responding to the right choice after chronic administration of 0.5 g/kg E. longifolia Jack, with more than 50% of the male rats scored right choice after 2 weeks post-treatment and the effect was more prominent at the dose of the observation period. However, there was no sexual enhancement of the middle aged male rats which consumed normal saline since only 45-55% of the male rats responded to right choice throughout the investigation period. Hence, this study shows that E. longifolia Jack enhanced the sexual qualities of the middle aged male rats, further supports the folkuse of E. longifolia Jack as an aphrodisiac.

PMID: 13678248 [PubMed - indexed for MEDLINE]

Aphrodisiac evaluation in non-copulator male rats after chronic administration of Eurycoma longifolia Jack.

·        Ang HH,

·        Ngai TH.

School of Pharmaceutical Sciences, University of Science Malaysia, Minden, 11800, Penang, Malaysia,
as reported in Fundam Clin Pharmacol. 2001 Aug;15(4):265-8.

The aphrodisiac effect of Eurycoma longifolia Jack (0.5 g/kg) was evaluated in noncopulator male rats using an electrical cage. Fractions of E. longifolia Jack decreased the hesitation time of noncopulator male rats, throughout the investigation period. Furthermore, it possessed a transient increase in the percentage of the male rats responding to the right choice, more than 50% of the male rats scored "right choice" after 3 weeks post-treatment and the effect became more prominent after 8 weeks post-treatment (only 40-50% of the control male rats responded to the right choice) using the electrical copulation cage. Hence, this study lends further support to the use of the plant by indigenous populations as a traditional medicine for its aphrodisiac property.

PMID: 11564133 [PubMed - indexed for MEDLINE]

Effects of Eurycoma longifolia jack on laevator ani muscle in both uncastrated and testosterone-stimulated castrated intact male rats.

·        Ang HH,

·        Cheang HS.

School of Pharmaceutical Sciences, University Science Malaysia, Minden, 11800, Penang, Malaysia. hhang@usm.my, as reported in Arch Pharm Res. 2001 Oct;24(5):437-40

It has been reported that Eurycoma longifolia Jack commonly known as Tongkat Ali has gained notoreity as a symbol of man's ego and strength by the Malaysian men because it increases male virility and sexual prowess during sexual activities. As such, the effects of 200, 400 and 800 mg/kg of butanol, methanol, water and chloroform fractions of E. longifolia Jack were studied on the laevator ani muscle in both uncastrated and testosterone-stimulated castrated intact male rats after dosing them for 12 consecutive weeks. Results 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 g body weight, respectively, when compared to control (untreated) in the testosterone-stimulated castrated intact male rats. Hence, the pro-androgenic effect as shown by this study further supported the traditional use of this plant as an aphrodisiac.

PMID: 11693547 [PubMed - indexed for MEDLINE]

Sexual arousal in sexually sluggish old male rats after oral administration of Eurycoma longifolia Jack.

·        Ang HH,

·        Lee KL,

·        Kiyoshi M.

School of Pharmaceutical Sciences, University Science Malaysia, Minden, Penang, Malaysia. hhang@usm.my, as reported in Basic Clin Physiol Pharmacol. 2004;15(3-4):303-9.

Eurycoma longifolia Jack commonly known as Tongkat Ali in Malaysia, has been used in Malaysia to increase male virility and sexual prowess. The objective of this study is to evaluate sexual arousal in sexually sluggish old male rats, 24 months old and retired breeders, receiving 200, 400, or 800 mg/kg of various fractions of E. longifolia Jack, twice daily, for 10 days. Control rats received 3 ml/kg of normal saline. The aphrodisiac effect was monitored by the act of yawning and stretching because yawning, either alone or associated with stretching, is considered an ancestral vestige surviving throughout evolution that promotes sexual arousal. The results showed that 800 mg/kg of E. longifolia Jack increased yawning by 50% and stretching by 16.7% in sexually sluggish old male rats, by 676-719% and 31-336%, respectively, in sexually active male rats, and by 22-44% and 75-100%, respectively, in middle aged, 9 months old and retired breeders. We conclude that the results of this study support the folk use of this plant as an aphrodisiac.

PMID: 15803965 [PubMed - indexed for MEDLINE]

Tongkat ali is also effective against germs
 

Antibacterial activity of Eurycoma longifolia Jack. A Malaysian medicinal plant.
Saudi Med J. 2007 Sep;28(9):1422-1424. Farouk AE, Benafri A. Biomolecular Engineering Research Unit, Department of Biotechnology Engineering, Kulliyyah of Engineering, International Islamic University Malaysia, Jalan Gombak, 53100, Kuala Lumpur, Malaysia.
       To evaluate methanolic, ethanolic, acetone and aqueous extracts from different parts of tongkat ali (leave, stem, and root) for antibacterial activity against Gram-positive and Gram-negative bacteria and to utilize the leaves and stem parts rather than the root, which is already used for male sexual enhancement in Malaysia. The alcoholic and acetone extracts from leaves and stems of tongkat alli contain potent antibacterial agent(s). This plant can serve as a potential source of antibacterial compounds.