They act to mosturize and desquamate dead skin. AHA's work best on the surface of the skin to remove dry skin or for thickened skin to remove outer layers. BHA's work better on opening up pores and are more effective in clearing up pimples. More is not necessarily better because these products can cause irritation. Some short-lived stinging upon application of products containing AHA is not uncommon.
Mechanical scrubs designed to remove dead skin are available in numerous formats.
They can cause irritation by abrading the skin. Retinoids Synthetic retinoids are used under a doctor's care to treat a number of skin conditions. Epidermal cell turnover is increased and the activity of UV stimulated enzymes that degrade collagen is decreased. It produces milder, more subtle effects on skin than tretinoin. Carotene, a water soluable precursor to vitamin A, is produced by many plants and animals.