There haven’t been many studies investigating the ergogenic effects of tongkat ali. A pilot study (presented as a conference abstract) in men who supplemented with 100 mg of tongkat ali during a 5-week circuit training intervention (60% 1-repetition max for 2 sets of 10 reps, 10 stations total, 1-minute rest intervals) noted that they experienced greater improvements in strength and lean body mass compared to a control group who trained without tongkat ali.[1]
Five weeks of tongkat ali supplementation (400 mg/day of extract) improved handgrip strength in older men and women between the ages of 57 and 72.[2] However, another study, which combined tongkat ali (200 mg/day) with a resistance training program, found no advantage compared to resistance training alone for muscular strength and power, although peak power output during a cycling test increased only in the combined group.[3] In the same study, tongkat ali supplementation alone did not affect performance outcomes.
In men with androgen deficiency of aging male (ADAM), 200 mg of tongkat ali with or without concurrent training for 6 months didn’t seem to provide an additional benefit above concurrent training alone for muscle strength, cardiorespiratory fitness, or symptoms of androgen deficiency in men;[4] or erectile function, sexual satisfaction, and testosterone levels.[5]
Tongkat ali doesn’t seem to improve endurance performance in the heat in recreational runners. Taking 150 mg of Eurycoma daily for 7 days and 1 hour before a time trial had no effect on running economy and performance or body temperature, heart rate, blood glucose, or lipid responses to exercise.[6]