Scientific Studies on Longjack

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Numerous scientific studies have demonstrated Eurycoma longifolia Jack (Longjack) effectiveness in enhancing sexual vitality and performance in men. Several publications based on scientific studies & medicinal reviews also reveal Eurycoma Longifolia Jack (Longjack) effectiveness in increasing muscle strength and size.

Longjack Review By Dr. Simon Chua, Department of Pharmaceutical Sciences, Wayne State University

In a preliminary study at the Reproductive Research Center in Kuala Lumpur , Malaysia , 30 married men, aged31-52 years old, took Longjack regularly for three consecutive weeks. Interviews indicated that 48% felt healthy, active and energized, and 40%felt increased sexual desire. The subjects showed an increased free testosterone index. Increased testosterone levels help improve libido, energy and muscle mass for bodybuilding. Their levels of DHEA, another critical steroid hormone, gradually increased from 26%after one week to 47% after three weeks. Most subjects demonstrated increased satisfaction in their sexual health and performance.

In addition, animal studies have shown that Longjack may increase testosterone availability as well as libido in mice. (Source: Article from the book Molecular Biology of the Cell, Published on: Sep 1, 2002)

Longjack Review By Dr. James Stoxen, Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago

The production of testosterone (the principal male-determining sex hormone) falls progressively from age 40. Experts call this “partial androgen deficiency of the aging male.” Androgens are steroid hormones with specific effects on tissue growth (muscle, fat, skin, hair and others) and brain function. They play important roles in men and women, but are produced in much larger quantities in men. In men after puberty, the testicles produce most androgens, mainly as testosterone. It has been suggested that Longjack may block negative feedback to the hypo-thalamus and pituitary glands, so the body continues to produce testosterone at elevated levels. (Source: Chapter 39-a from the book Eureka Bioscience Collection , Published on: 3 rd Oct, 2003)

Longjack Review By Ang HH, Ikeda S, Gan EK. School of Pharmaceutical Sciences,
University Science Malaysia, Minden, Penang, Malaysia

The butanol, methanol, water and chloroform extracts of the roots of Eurycoma longifolia Jack were studied using various tests of potency of treated male rats. The results showed that E. longifolia produced a dose-dependent, recurrent and significant increase in the episodes of penile reflexes as evidenced by increases in quick flips, long flips and erections of the treated male rats during the 30 min observation period. These results provide further evidence that E. longifolia increases the aphrodisiac potency activity in treated animals. (Source: Journal index for medicine© 2001 John Wiley & Sons, Ltd, Published on: Dec 2005.)

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