How Deep Does a Light AHA Peel Penetrate?

My answer is to the directed question of the effect upon ONLY the "top" of the skin. YES! But there is minimal deeper penetration. From MIAMI Dr. Darryl J. Blinski

Alpha-hydroxy acids (AHA) are known for their use as a superficial chemical peeling agents in skin therapy. They are used to reduce superficial keratosis (extra keratin produced by skin due to sun damage), mild epidermal dyschromia (color alteration) and comedome (blackhead and whitehead) formation. Repeated applications may create some change in the upper dermis with a subtle smoothing of the mildest wrinkles. However, for more advanced characteristics of aging and sun damage the... more

The low strength glycolic peels really don't penetrate the dermis to any significant degree.  That's why their results are so minimal and are just surface refinements, not the development of all new skin.