Eurycoma longifolia is a flowering plant native to Indonesia and Malaysia. As a testosterone booster, it is better known as Tongkat ali or Longifolia Jack.
In South East Asia, Tongkat ali has long been used in traditional healing practices. Nowadays, Tongkat ali is a common additive in foods, beverages, and supplements.
What do the studies say about Tongkat ali and testosterone?
a) A Malaysian study from 2012 revealed that, during a 6-month trial, Tongkat ali increased sperm mobility by 44% and volume by 12% when compared to a control group. Moreover, libido and erectile function were reported to have improved in the group of men taking Tongkat ali. 1
b) In another promising study concerning male hormones, 63 study subjects suffering from stress were given Tongkat ali for 4 weeks. Following the supplementation period, the sense of stress was reduced by 16%, while levels of the stress hormone cortisol were reduced by 16% and testosterone levels rose by 37%. 2
c) Once again in a Malaysian study, 200 mg of Tongkat ali was administered daily for a month to men who had developed hypogonadism in their adult years. Over 80% of the men in this trial who suffered from low testosterone had their T-levels increased to normal healthy levels. This study did not have a control group and it does not give an indication of how Tongkat ali would have performed in men whose testosterone levels are normal to begin with. 3
d) In addition to these studies, one in vitro experiment showed Tongkat ali to be very anti-estrogenic. As this is a test tube study, it does not necessarily correspond well to mechanisms taking place in human bodies. 4
The usage and safety of Tongkat ali
The usage of any supplement should be considered carefully. It can be assumed that many commonly used and studied supplements, such as vitamin D, zinc or magnesium are fairly safe. More criticism and deliberation should be exercised when dealing with more rare and exotic supplements like Tongkat ali.
Some years ago, I experimented with a supplement regimen whereby I cycled different testosterone boosting herbs every day of the week. Tongkat ali felt like the most powerful supplement at the time for me. At wrestling practices, I was irritated when the training hours ended, and wanted to continue. I had a lot of energy all the time and my girlfriend claimed that I smelled of testosterone – whatever that means.
After a month of this herbal cycling, I noticed that my skin had started to turn frighteningly yellowish, from the hands most notably. After that, I stopped taking most of the testosterone boosters, including Tongkat ali. I’m not certain if the yellowish skin was caused by Tongkat ali, but I haven’t taken this herb since. The yellow hue cleared off from the skin in a few days and hasn’t returned since.
The typically dosage for Tongkat ali is: 100 – 200mg, with 100:1 extract. In a rat study, a dosage which would be equivalent to 1200mg for humans, caused liver diseases in rodents. 5
1. Ismail S, Wan M, George A, Nik H, Musthapa K, Liske E. 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. Evid Based Complement Alternat Med. 2012;2012:429268. [PubMed]
2. Talbott S, Talbott J, George A, Pugh M. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013;10(1):28. [PubMed]
3. Tambi M, Imran M, Henkel R. Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia. 2012;44 Suppl 1:226-230. [PubMed]
4. Teh C, Abdulghani M, Morita H, Shiro M, Hussin A, Chan K. Comparative X-ray and conformational analysis of a new crystal of 13α,21-dihydroeurycomanone with eurycomanone from Eurycoma longifolia and their anti-estrogenic activity using the uterotrophic assay. Planta Med. 2011;77(2):128-132. [PubMed]
5. Shuid AN, Siang LK, Chin TG, Muhammad N, Mohamed N, Soelaiman IN. Acute and Subacute Toxicity Studies of Eurycoma longifolia in Male Rats. International J of Pharmacology. 2011;7(5):641-646. doi: 10.3923/ijp.2011.641.646