combination mimics the natural components of the skin and is an ideal composition for augmenting soft tissue in mammals the ha and collagen gel of the present invention has improved rheological properties and volume stability or persistence compared to a single component formulation of ha such as captique u2122 or a single component formulation of collagen such as cosmoplast u00ae the process of the present invention involves obtaining ha either in solid or liquid form and cross linking ha as a concentrated solution followed by the addition of collagen and finally more ha the collagen of the present invention primarily derives from mammalian source materials such as bovine or porcine corium or tendon or human placental tissue collagen produced from human fibroblast cell culture or recombinantly produced collagen expressed from a cell line may also be used base e g naoh is first added to ha to adjust the ph to 9 12 a cross linker is added to the ha and the reaction is allowed to proceed collagen ph 2 3 is then added the collagen reacts with the cross linker to covalently bind to ha the cross linker is consumed lightly in cross linking the collagen a ha solution is added as a lubricant and cross linker scavenger the final formulation has a core of cross linked ha with collagen lightly cross linked and surrounding the ha core the additional soluble ha consumes the residual cross linker and adds a lubrication benefit generally any cross linker that induces covalent bonds linking ha and collagen molecules may be used examples of such cross linkers include but are not limited to vs bdde.