Both the glycolic and the lactic have anti-aging effects, but in different ways. The Glycolic works mainly underneath the skin, while the lactic works on the surface of the skin. Glycolic acid is the smallest Alpha Hydroxy Acid (AHA), Lactic acid is slightly larger. Glycolic, because of its small size is able to penetrate deeper into the dermis. It has received the most attention from the medical community, and is generally considered the best AHA to treat fine lines and wrinkles. Lactic acid because of its slightly larger molecule is slightly less harsh on the skin. It acts naturally as a humectant to pull moisture into the skin, and is part of mammalian skin physiology, meaning it occurs naturally in the body. It is generally considered best for treating pigmentation and skin spots. TCA is also a good peel for anti-aging as it is a more powerful exfoliator than the other acids and has the ability to penetrate slightly deeper into the surface levels.