Evidence Level
Moderate
Tongkat ali has a growing body of clinical evidence, particularly from Malaysian research groups. Talbott et al. (2013) published one of the most cited studies, demonstrating significant testosterone increases and cortisol reductions in moderately stressed adults. Ismail et al. (2012) showed benefits for late-onset hypogonadism. Tambi et al. (2012) provided the largest fertility dataset (n=350) with notable pregnancy rate improvements. However, many studies have been industry-funded and used the patented Physta extract. Independent replication with diverse populations is needed. A 2022 systematic review (Thu et al.) concluded there is "promising but not conclusive" evidence for testosterone and male fertility benefits.