I first heard of telomeres over a year ago. Some scientists speculated that telomeres held the secret to aging (or staying young and cancer free), detractors said it was nothing more than speculation, an unproven theory. Now, however, a cosmetic ingredient called trepenone and marketed as Renovage is cropping up more and more - Jan Marini and features in her Regeneration Booster product, we saw it in YBF's new Boost and it in the latest eye cream from Osmotics called Renovage Cellular Eye Repair. So what are telomeres anyway.

Telomeres allow cells to distinguish chromosome ends from broken DNA. If DNA is broken there are two options after the cell cycle is stopped: Repair or death. If cells divided without telomeres, they would lose the end of their chromosomes, and the necessary information it contains. They are often described as being like the tips on the ends of shoelaces that stop them unraveling (the pink bits in the image above).

Telomeres shorten every time a cell divides. When they become very short, they trigger cell crisis and cell death. As we know, cells can only replicate a limited number of times - a phenomena called the Hayflick Limit. Cells removed from a newborn infant and placed in culture will go on to divide almost 100 times. Well before the end, however, their rate of mitosis declines (to less than once every two weeks). Were my cells to be cultured when I am in my late 70s, they would manage only a couple of dozen mitoses before they ceased dividing and died out.

An important aside: when I learned about the Hayflick Limit, it confirmed my view that too many treatments - such as laser, or thermage - that promote more rapid cell turnover are a bad idea. This is because they hasten the arrival of the inevitable HayFlick Limit.

Advocates of human life extension promote the idea of lengthening the telomeres in certain cells through temporary activation of telomerase (by drugs), or possibly permanently by gene therapy. They reason that this would extend human life. So far these ideas have not been proven in humans. Plus there are fears that lengthened telomeres would be more susceptible to cancer. Anyhow, not all scientists believe that cell death is the cause of aging (but just a symptom) so they say that lengthening the telomeres would not correspondingly lengthen life.

In cosmetics, the objective is slightly less ambitious - rather than try to lengthen the teleomeres, products such as Renovage promise to stabilize them so that at least they won't shorten. Maintaining telomere length extends, we are told, the Hayflick Limit by one third. Should we believe this? Well, Renovage is made by a French company called Sederma, the lovely people that gave us the power peptide Matrixyl 3000. Although the supporting data comes from studies conducted by Sederma itself, its track record with effective ingredients such as Matrixyl, speaks for itself.