"Monophasic" describes the structure of the gel rather than a marketing claim: a single homogeneous mass instead of particles suspended in a carrier fluid. That structural difference is what shows up in how the result feels and flows under the skin.
Cross-linking and result longevity
The degree of cross-linking determines how the gel resists natural enzymatic breakdown. More cross-linking means longer persistence and greater resistance to migration; less means the higher flow that delicate areas need. The range of densities is not commercial variety — it matches the intended depth of injection.
Purity of the material
The raw material is produced by biofermentation and passes through multiple purification stages to reduce residual cross-linker as far as possible. Purity here is a question of tissue tolerance before it is a number on a leaflet.