Alpha hydroxy acids (glycolic and lactic are the most commonly used) are derived from certain plants, many of them fruits, giving AHAs their familiar nickname of "fruit acids." AHA creams are said to help with stretch marks because they moisturize the outer layer of skin, making it more pliable. These products increase cell regeneration by "burning off" the outer layer of skin cells. By removing the top layer of cells, healthier cells come to the surface, improving skin texture and color, and allowing moisturizers to be absorbed so the skin remains supple. While penetrating the skin's surface, the water-binding properties of alpha hydroxy acids increase the skin's flexibility and assist in stretch mark reduction. Though your skin may feel dry and flaky at first from the dead cells being sloughed away, after a few weeks, AHAs will almost certainly make your skin feel and appear smoother -- and visibly reduce stretch marks. If you stop using alpha hydroxys, the skin will return to its normal state since cell regeneration is no longer taking place.