Eurycoma Longifolia
Eurycoma longifolia also known as tongkat ali and long jack, is commonly seen in testosterone boosters and is heavily pushed as being one of the few clinically proven ingredients that can boost testosterone effectively in healthy males. Independent research, however, suggests that may be stretching the truth a bit, although despite that the ingredient is not useless and does offer users some significant benefits.
What it does
Eurycoma Longifolia has been shown to help significantly reduce the stress hormone cortisol providing a 16% reduction in users, while simultaneously lowering levels of tension, anger, and confusion by 11-15%. In the same study, researchers showed that while this herb does increase testosterone, it was only by 37%; not enough to impact muscle growth[1].
One anecdotal benefit of eurycoma longifolia that has been repeated in clinical trials is the increase of libido/occurrence of erections[2], making it a very popular male enhancement ingredient. This same study also noted that overweight users (those with a BMI over 25) experienced minor weight loss while using this ingredient. Both of those benefits were proven in a study that was funded by the producers of the supplement.
How it works
The purported mechanism of action for eurycoma longifolia resides in its quassinoid compounds such as eurycolactones and glycosaponins. Unfortunately, due to the lack of in depth investigation into active ingredients, little is available to properly speculate how these specific compounds interact with the body to provide supposed testosterone, erectile/libido, or muscle growth actions.
Dosing
Standard dosing protocol is to use 300-600mg each day, taken in two doses. For best results, take 150-300mg upon waking, and an additional 150-300mg 8-12 hours later.