From Ergo Log
Tongkat Ali is an interesting supplement for athletes over the age of 55. Ralf Henkel of the University of the Western Cape in South African and Ruxiang Wang of the Shenyang Center for Disease Control and Prevention in China drew this conclusion after performing an experiment with 25 older cyclists. Tongkat Ali supplementation gave the cyclists more muscle power and boosted their testosterone levels.
Tongkat Ali, an extract of the roots of the Eurycoma longifolia bush, contains the compounds eurycomanone and 13-alpha (21)-expoxy-eurycomanone. These boost testosterone production in a way that seems to indicate that there's an anti-oestrogenic mechanism at work.
In Asian countries Tongkat Ali has been a popular remedy for complaints associated with aging especially among elderly men. Sponsored studies confirm its effectiveness. Tongkat Ali boosts the testosterone level of men in their fifties who have low testosterone production – by a small amount.
These men did not all have the same level of fitness, however. The researchers wanted to know whether Tongkat Ali would also have a positive effect on older athletes – so they performed an experiment with 13 male and 12 female amateur cyclists aged between 57 and 72. All were members of a cycling club in Shenyang, China.
The researchers gave their subjects two capsules containing 200 mg Tongkat Ali extract daily for a period of five weeks. They used Physta extract, manufactured by Biotropics Malaysia Berhad – and yes, this company happened to also sponsor the study.
The researchers measured the concentrations of DHEA, cortisol and IGF-1 in the subjects' blood, but observed no noticeable effects. Not much happened to the SHBG either. But Tongkat Ali did have an effect on the subjects' testosterone levels.
The first figure below shows that Tongkat Ali boosted both the total testosterone level and the level of free testosterone in the men. The second figure shows the same but for the women.
If androgen levels rise, you'd expect muscle strength to increase too. This was indeed the case, as the researchers discovered when they measured the force with which the subjects were able to operate a handgrip.
The subjects were enthusiastic about the effects of the supplement. When the researchers asked them whether they thought that Tongkat Ali was good for their health and whether they would want to continue using the supplement, they all gave an affirmative response.
The majority also responded positively to the question whether Tongkat Ali had increased the subjects' desire to exercise or their physical endurance capacity.
"This observational study on the effect of a standardized water-soluble extract of Tongkat Ali has shown that the herbal supplement had no adverse effects and is acceptable to the senior recreational athlete as a form of health supplement for general well-being", the researchers conclude. "The study has affirmed the ergogenic benefit of Tongkat Ali for physically active seniors and has the potential to assist the elderly to exercise, thereby enhancing health and wellness, through enhanced muscle strength."
Phytother Res. 2013 Jun 11. doi: 10.1002/ptr.5017. [Epub ahead of print].