I recently did a little online research into some popular cosmetic ingredients to see what the claims are.  The biochemist in me wanted to know if they really work and how do they work?  This is a summary of what I found.

Alpha-hydroxy acids are also listed on the label as glycolic acid, lactic acid, and fruit acids.  These acids dissolve the glue that holds together epidermal cells and allows them to sloiugh off.  These may stimulate collagen production.  But they also increase sun sensitivity.

Retinol is a deriviative of vitamin A.  It stimulates cell growth in the skin and increases collagen production.  It is used in both acne and anti-aging products.  It can be irritating.

Pentapeptides look like small pieces of collagen and tell the cells to make more collagen.  They also help to deliver copper to the skin and can diminish roughness.  They are less irritating than retinol.

Vitamin C is an anti-oxidant.  It stimulates collagen production and brightens skin by inhibiting melanin production.

Vitamin E is another anti-oxidant.  It protects from UV irradiation and is used to treat scars by softening the collagen in them.

Tea tree oil is a natural antiseptic.  When used to treat acne, it is as effective as benzoyl peroxide.

Is there anything in your cosmetics that you would like me to research?  Let me know and I'll see what I can find out.