Eurycoma longifolia, commonly known as Tongkat Ali is best known for its sexual enhancement features. It is cultivated exclusively in Southeast Asia.

Tongkat ali has been used in Malaysia for many years by men who want to increase their sexual desire, libido, sexual performance or to treat erectile dysfunction.

 
Tongkat Ali appears to work by increasing the levels of testosterone, which is responsible for the growth and development of human reproductive organs.

It is also used to increase muscle mass and allow better recovery from physical exertion.