4-hydroxyisoleucine is a non-protein amino acid which exists in fenugreek plants, mainly in fenugreek seeds, with the effect of promoting the insulin secretion. In addition, 4-hydroxy-isoleucine could enhance the creatine entering into the muscle cells. It could improve the muscle strength and lean muscle mass, and increase the strength and size of muscle cells. 4-hydroxyisoleucine, a natural phytochemical extracted from the Fenugreek herb, has been scientifically shown to increase carbohydrate storage in muscle cells while decreasing carbohydrate fat storage through the sensitizing of insulin receptors in muscle tissue. 4-hydroxyisoleucine has also been shown to interfere with the process by which the body converts muscle protein to sugar for energy. This encourages fat loss (instead of muscle break down) and aids in the retention of calorie-burning lean muscle as you lose fat.