AbstractThe present work applies the law of mass conservation toward an analytical model describing the long-term degradation of Mg-0.3Ca implant material in defined physiological electrolyte environments. The model takes into account surface conversion and degradation product deposition related changes of degradation rates by introducing an effective layer thickness. The analytical nature of the approach does not consider detailed chemical and electrochemical process. Thus, it simply declares an effective damping term. In this way it can be applied easily for the prediction of materials failure in the named environments. Restrictions of the approach will be discussed as well since validity relates to a number of aspects.