Since ancient times, mankind has sought the gift of eternal youth and many have claimed to have discovered the secret. Today, despite a plethora of products promising a more youthful appearance, ways to truly defy the passage of time remain elusive – and difficult to substantiate. Although determining chronological age is straightforward, establishing physiological age has remained subjective. Research by scientists at the Buck Institute for Age Research however, could now lead to biomarkers to test the claims of anti-ageing therapies. The work was carried out in nematode worms and, by looking at changes in gene expression, the group identified a suite of genes that are actively involved in the ageing process. This is the first step towards identifying similar, irrefutable, biomarkers in humans that would provide a way of testing the effectiveness of anti-ageing therapies. The technology would also provide a way of telling whether an individual is ageing more quickly or slowly than would be expected. By extending their studies to mice, the scientists hope to be able to answer questions about the effects of environmental and nutritional factors on ageing. The work is published in the November 20, 2008 online edition of Aging Cell.