The objective for anti-aging skin care products is to increase the presence of collagen, elastin, ceramides and keratin, all of which contribute to skin's firmness and structural integrity.

• Collagen is the main structural protein found in skin and it provides rigidity.
• Elastin is the component of the skin that gives it flexibility and allows it to snap back.
• Ceramides are the fat based (lipid) chemicals that bind skin together on the topmost layer of your skin (the stratum corneum).
• Keratin is tough protein made of amino acids, carbohydrates, and fatty acids that provides flexibility and protection.

If topical application of collagen, elastin, ceramides, and keratin increased the amount of these components in your skin cells, skin care would be a breeze. Unfortunately, for the most part, these molecules are ineffective as a topical ingredient because they are too large to penetrate the outer layers of the skin.

Cosmeceuticals promise to fight aging with brilliant lab discoveries of new ingredients and delivery mechanisms. Unfortunately, most ingredients do not penetrate the skin very well. Fatty lipids, smaller sized molecules (nanoparticles) and ingredients suspended in silica shells have the best chance. It is most likely that the ingredients in many of our products simply sit on top of our skin until we wash them off.

The ingredients discussed below, when presented in the proper form, are able to penetrate the dermis and improve skin condition.

Vitamin A

Topically applied, vitamin A can partially reverse structural changes to the skin caused by sun damage and aging. Vitamin A enhances the production of collagen, smooths skin by communicating with the genes involved in epidermal cell turn over, and acts as an antioxidant.

The active form of vitamin A is called retinoic acid. Prescription vitamin A products contain retinoic acid in the form of either tretinoin or synthetic tretinoin (adapalene and tazarotene). Synthetic tretinoin is not as successful as true tretinoin in reversing wrinkles. With adapalene, for example, the acid only binds to 1 out of 3 potential skin receptors. The advantage to this is that the synthetic products have less side effects such as irritation and redness. The disadvantage is less wrinkle reversal.

There are a variety of vitamin A products that contain retinoic acid.

• Differin Gel (adapalene). This product is now available over the counter. The gel allows for increased absorption and less light sensitivity. This product is an excellent acne treatment.
• Retin A (tretinoin). Retin A has the most research-based support for its acne and wrinkle reducing abilities. It is available only by prescription. Some users find it too irritating.
• Renova (tretinoin). Renova also contains true tretinoin in an emollient cream. It is available only by prescription.
• Tazorac cream (tazarotene). Use this cream to treat psoriasis.

If you don't have a prescription for vitamin A you can buy a product with retinol (rather than with retinoic acid). Retinol is the name for the entire vitamin A molecule. Your skin will incorporate the retinol and convert it into retinoic acid. The conversion process weakens the active ingredients so a retinoid product with .5% active ingredient is comparable with a dose of .05% retinoic acid product.

In cosmetics, the percentage of retinol, the delivery system, packaging and other ingredients present are all important. Retinoids are air and light sensitive. It is best to purchase a product packaged in a tube or a dark pump rather than a clear bottle.

There are several types of retinol found in cosmetic products. These include retinyl acetate, retinyl linoleate, retinyl propionate (a retinol ester), retinyl retinoate (possibly the most effective form of retinol), retinyl palmitate (the least effective form of retinol, useful for sensitive skin).