Longjack, also known as Tongkat ali and pasak bumi, is a shrub hailing from Southeast Asia purporting to improve libido. It’s gaining traction in the scientific community for potentially increasing testosterone levels, and researchers at South Africa’s University of the Western Cape found that longjack improved testosterone levels and muscular strength in physically active seniors (a population with typically low testosterone).
However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
Bhatia et al (2006) studied 70 male patients with type2 diabetes mellitus (age range 24–78 years). Thirty-seven subjects were found to have hypogonadism based on a calculated free testosterone level of less than 6.5 μg/dl. The hypogonadal group had a statistically significant lower hematocrit. Anemia was observed in 23% of the patients (16 out of 70). In 14 of 15 anemic patients calculated free testosterone was low.