There are many other non-prescription topicals for sale in stores or on the Net that claim to improve the health of the skin. Most are simply expensive cosmetics that may temporarily improve the appearance of the epidermis without affecting skin biology. Unless you can confirm that these products are supported by medical studies published in a peer-reviewed medical journal, you shouldn't waste any money on them. You will probably be able to get the same effects with low-cost products such as moisturizers.

There is a gray area of products on the market that have been examined in a small number of medical studies and that may improve skin biology in some way. There are lots of these products including special vitamin formulations, alpha-lipoic acid, green tea, palmitoyl pentapeptide, epidermal growth factor, and furfuryladenine (Kinerase and Kinetin).

Generally, the claims made for these products include delivery of anti-oxidants into the dermis, smoothing of the epidermis, or improvement of collagen and elastin. These products are more expensive than retinol, copper peptide, or AHAs, and many are even more expensive than prescription tretinoin. You may see them advertised in fashion magazines. Some are sold at upscale department stores for very high prices.

Obviously, you don't want to spend a lot of money trying all of these products. Because they are expensive, you should have some assurance that they actually work. Many people have the mistaken belief that laws restrict the advertising of skincare products.

In fact, companies can make all sorts of vague claims about skin improvement so long as they don't claim the product affects the "structure or function" of the skin. To determine if these products really work, you need to do your own research and rely on the scientific studies.

Cod Liver Oil and Zinc Oxide

Currently, there are only a small number of published medical studies on these gray area products. Most of the studies are not double-blind, or only use a small number of subjects, so the results are not considered scientifically convincing or statistically significant.

In fact, positive results in small-sample studies can be due to the placebo effect, where some qualitative improvement is reported even with skin creams that have no active ingredients. So unlike retinoids and cosmetic acids, dermatologists do not yet agree on the effectiveness, biochemical action, or safety of these products.

Net reviews from users of these products are all over the map, with some people reporting improvement and others reporting no effect at all. Some of these products may work, but unless you are wealthy and have money to spend experimenting, it is better to wait until there is more scientific proof of their effectiveness.

If you want to see if more medical studies have been done on a particular skin product, try searching on the the chemical name of the active ingredient in the Internet medical index Medline (available free on many websites such as the National Library of Medicine, www.ncbi.nlm.nih.gov with short study abstracts).

There are a couple of other effective, proven topical treatments that should be mentioned, if only because they are so inexpensive. There are a variety of chemicals that have been found to improve epidermal growth after skin abrasions. Two of these cost only a few dollars and are available at drug stores.

Both cod liver oil (which is rich in vitamin A) and zinc oxide have been found in animal studies to significantly improve epidermal healing when compared to unmedicated products like plain petroleum jelly. One study also found them to be synergistic when applied together. See for example "Improvement and Retardation of Wound Healing: Effects of Pharmacological Agents in Laboratory Animal Studies," Veterinary Dermatology, 10(2), 83-88, 1999; "Topical Application of Cod Liver Oil Ointment Accelerates Wound Healing," Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery, 34(1), 15-20, 2000 Mar; and "Enhancement of Re-Epithelialization with Topical Zinc Oxide in PorcinePartial-Thickness Wounds," Journal of Surgical Research, 50(2), 101-105, 1991 Feb (abstracts available on Medline).

Cod liver oil and zinc oxide won't do anything for lines and wrinkles in the dermis, but they may help smooth the epidermis if used regularly. There are some skincare products available in drug stores that contain both cod liver oil and zinc oxide. These are usually in the first-aid or baby-care sections. However, some of these products may have too much fragrance for use on the face because they are marketed for diaper-rash. Try to find one without fragrance listed in the ingredients; some generic drug store-brands have no fragrance.

Also try to find a cream or lotion, rather than an ointment (which contains mineral oil or petroleum jelly); the latter are too greasy for most people. Cod liver oil (in capsules or bottles) and plain zinc oxide ointment can also be purchased separately, but unless you have very dry skin, they leave an oily film on the face.

Undiluted cod liver oil also has a slight fish odor. All of these products are only appropriate for use at home or while sleeping, because the zinc oxide leaves a noticeable faint white color on the face until it is washed off. They may also stain fabrics, so if you apply them before sleeping, use old sheets and pillowcases.