Strengths: Some antioxidant-rich products in stable packaging; almost all sunscreens offer sufficient UVA protection; mostly fragrance-free products.
Weaknesses: Cleanser; toning mist; some moisturizers and a serum with irritating ingredients; the Clear Skin product; unknowns about topical application of kinetin and zeatin.
Valeant Pharmaceuticals owns and distributes this medically positioned line that's built around the ingredient kinetin, a plant-growth hormone whose technical name is N6-furfuryladenine. What makes kinetin interesting are the in vitro and animal studies demonstrating its effect as a growth factor. Most of these studies were conducted by Dr. Suresh I. S. Rattan, Ph.D., D.Sc., Associate Professor of Biogerontology at the University of Aarhus, Denmark, who happens to hold the patent for use of N6-furfuryladenine on aging skin.
Dr. Rattan told me in an interview, "Normal cells, as they divide and age, go through a progressive accumulation of changes that are irreversible until they reach a stage where they finally die. The in vitro form of creating cellular aging is called the Hayflick Phenomenon, named after the researcher who discovered this method of studying cellular aging in a laboratory setting." He went on to state that "a young cell is plump, round, smooth. As the cells age, they become irregular, flattened, and large, full of debris.… When you grow normal cells in the lab they have a limited number of times they multiply and divide—termed a cell's replicative life span. But when I added N6-furfuryladenine to these cultures the cells did not age as fast, the process slowed down dramatically…" On the flip side, Dr. Rattan mentioned, "We are curious about negative effects.... In cell cultures when a concentration of, say, 250 micromolars of N6-furfuryladenine was used, we got good results, but when we used 500 micromolars of N6-furfuryladenine the cells started dying." The quotes above are from my original phone interview with Dr. Rattan prior to my first reviews of products containing kinetin. He has since told me we can no longer have discussions about this ingredient, not a shock given that "loose lips often sink ships."
You may be wondering if, years later, there is any new research that finally shows kinetin to be a worthwhile ingredient to add to your "anti-aging" skin-care regimen. One published study examined the effect of applying a low dose of kinetin to the skin of hairless dogs. The applications lasted 100 days, and gradual skin texture, wrinkle, and depigmentation (skin lightening) improvement was observed in all subjects. However, the study was not done double-blind, it wasn't compared to a placebo, and dogs don't wrinkle or age the way we do. So it's really a stretch to suggest that the results on dog skin somehow translate to results on human skin (Source: Rejuvenation Research, Spring 2004, pages 32–39). Further and more recent research on kinetin hasn't proven it to be an antiwrinkle luminary or even a dim light (Source: Annals of the New York Academy of Sciences, May 2006, pages 332–342).
Using kinetin on skin remains as much of an unknown as it was when we first wrote about it. There are also conflicting results from studies trying to answer such questions as: How much kinetin is needed to have an effect? Can you use too much? How do you control the amount of skin cell differentiation? Can it exert antioxidant activity? The bottom line is that even if kinetin could be used by skin cells, there probably isn't enough kinetin in any product to have a negative or positive impact. However, that is only a guess; no one knows for sure, and so using products with kinetin remains potentially effective but still questionable. Besides, you have to ask yourself: If kinetin is such a miraculous ingredient, why aren't other companies using it in their products? Thus far, the licensing rights to kinetin haven't been setting the industry afire, and it's doubtful much more than a spark will be generated because everyone is always looking for the next buzz ingredient.
(Sources for the above: Biochemical and Biophysical Research Communications, June 1994, pages 665–672, November 1999, pages 499–502, and October 2000, pages 1265–1270; Bioorganic and Medicinal Chemistry, May 2002, pages 1581–1586; and Dermatologic Clinics, October 2000, pages 609–615.)
For more information about Kinerase, call 1-800-321-4576 or visit www.kinerase.com.