Belotero is a cross-linked hyaluronic acid. Hyaluronic acid occurs naturally in the skin, and it attracts water, increasing the fullness or plumpness of the skin. As we age, we lose hyaluronic acid from the skin, resulting in loss of fullness and deflation. Injecting Belotero can increase the fullness and inflate the skin. An advantage of Belotero to all other hyaluronic acid fillers is that is specially formulated to avoid appearing blue under the skin. Many hyaluronic acid fillers that are placed too superficially can appear blue like how our veins appear blue. The fact that hyaluronic acid occurs naturally in the skin accounts for the low incidence of allergic reaction to Belotero.