Advanced glycation endproducts, also known as AGEs, are caused by the body's major fuel source, namely glucose. This simple sugar is essential for energy, yet it also can bind strongly to proteins (the body's fundamental building blocks) and form abnormal structures (AGEs) that progressively damage tissue elasticity. The glucose itself isn’t damaging, it’s what happens when glucose transforms into AGEs that’s the problem. Refined sugar from our diets is a major source of AGEs, and more research is revealing a diet high in sugar causes the body to age faster (Source: Cosmetics & Toiletries, June 2011, pages 438–444).
Once AGEs are generated, they begin a process that prevents many systems from behaving normally by literally causing tissue to cross-link and become hardened (Source: Proceedings of the National Academy of Sciences, USA, March 14, 2000, pages 2809–2813). In skin this damage occurs to collagen and elastin, the chief ingredients responsible for skin’s firmness and ability to bounce back when stretched. AGEs also cause inflammation within the body, which is believed to play a widespread role in how we age and become more prone to disease.
The theory is that by breaking these AGE bonds you can undo or stop the damage they cause. There are studies showing aminoguanidine and carnosine to be AGE inhibitors that can prevent glucose cross-linking of proteins and the loss of elasticity associated with aging and diabetes, but many other substances are potential candidates as AGE inhibitors as well.
One study examined over 92 substances and 29 of them showed some degree of inhibitory activity, with 9 compounds proving to be 30 to 40 times stronger than aminoguanidine (Source: Molecular Cell Biology Research Communications, June 2000, pages 360–366). Carnosine, in particular, is considered a very good inhibitor of AGEs.
AGEs and free-radical damage may be inextricably linked (Sources: European Journal of Neuroscience, December 2001, page 1,961; and Neuroscience Letters, October 2001, pages 29–32), but none of this has been shown to have relevance when it comes to topical application of these substances when they are included in cosmetics.
It is possible in the future that skin-care products will be formulated with ingredients proven to effect the formation of AGEs when applied topically. For now, eating a low sugar diet rich in antioxidants and anti-inflammatory ingredients is the best approach.