What do studies say about Hautalterung Basis?

The provided context documents do not contain any specific studies or information on the topic 'Hautalterung Basis' (skin aging basics). The included sources cover nutrition tests, DNA tests (e.g., MC4R, MTHFR), and microbiome tests, but not skin aging. Without direct evidence from the context, I cannot provide a substantiated statement about studies on skin aging. It is generally known that skin aging is influenced by intrinsic (genetic) and extrinsic (UV radiation, nutrition, lifestyle) factors, but the data here do not support specific claims. The evidence level is therefore 'weak' or 'insufficient'.