''People between the ages of twenty and thirty produce an increased amount of testosterone when they take 400 milligrams of Tongkat Ali daily'' - University of Malaya.
The study
A recent study conducted by scientists at the University of Malaya in Malaysia involved a 14-day period in which 16 men between the ages of 18 and 30 were given 600 milligrams of Tongkat Ali extract daily. This extract, called Physta, is water-based and is produced by Biotropics Malaysia Berhad [biotropicsmalaysia.com].
The daily supplementation resulted in an intake of 8.7 milligrams of eurycomanone, the main active ingredients in Tongkat Ali.
Results
Supplementation with Tongkat Ali increased the concentration of free and total testosterone by 34 and 25 percent respectively. In the supplementation group, estradiol levels increased by 51 percent.
Source: https://onlinelibrary.wiley.com/doi/10.1111/and.14001