As there's only the one ingredient in Testojack we're going dive a little bit deeper into the pros and cons of Tongkat Ali than we would normally do for a single ingredient. We do like Tongkat Ali as an ingredient for test boosters and sexual health products, so let's have a look at why it's beneficial and why it is a good ingredient, but not the best option. Now foods do offer most of the other better testosterone boosters as individual products as well, but typically we prefer good combined products to maximise returns as not every ingredient tends to work for every individual so properly dosed blends cover more bases.
Tongkat ali is a natural aphrodisiac that has been used in traditional medicine to treat a wide range of sexual problems. That said we could only find one study that showed significant improvement in sexual performance and libido in men and women, this study also noted that the participants with notably improved desire had previously had 50% lower testosterone levels than the base line of other participants.
Longjack (the other name for tongkat ali) is known to boost testosterone levels by increasing the production of this hormone. In fact, some studies have found that it can increase testosterone levels by as much as 50%. However, this was a one off against particularly low test levels (and in women a fact which is often neglected when people selling the supplement cite this study) [1] with most cases showing increases substantially lower, although still consistent statistically significant increases. But, they're more akin to 10-15% making it a good ingredient to combine with other testosterone boosters, but not a fantastic standalone.
Aside from this Tongkat has been shown to be quite effective as a stress reducer, again, not as good as ashwagandha or as well studied, it is still a notable benefit especially in the context of testosterone production as cortisol (the stress hormone) lowers production significantly.
All of this said however, treating common vitamin deficiencies such as vitamin d and zinc (which combined effect more than half the adult US population) will have a substantially larger effect on testosterone production. With even small zinc deficiencies causing dramatic testosterone decline. We'd suggest testing a combined testosterone booster or even a mens multivitamin before solely using a tongkat ali supplement.
1 - https://pubmed.ncbi.nlm.nih.gov/23754792/
2 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3669033/