This review focusses on the application of physiological conditions for the mechanistic understanding of magnesium degradation. Despite the undisputed relevance of simplified laboratory setups for alloy screening purposes, realistic and predictive in vitro setups are needed. Due to the complexity of these systems, the review gives an overview about technical measures, defines some caveats and can be used as a guideline for the establishment of harmonized laboratory approaches.

Although certified magnesium‐based implants are launched some years ago, the not well‐defined Mg degradation mechanism under physiological conditions makes it difficult to standardize its use as a degradable biomaterial for a wide range of implant applications. Among other variables influencing the Mg degradation mechanism, monitoring the pH in the corrosive solution and, especially, at the corroding interface is important due to its direct relation with the formation and stability of the degradation products layer. The interface pH (pH at the Mg/solution interface) developed on Mg‐2Ag and E11 alloys are studied in situ during immersion under dynamic conditions (1.5 mL min^‐1) in HBSS with and without the physiological amount of Ca²⁺ cations (2.5 × 10^‐3 m). The results show that the precipitation/dissolution of amorphous phosphate‐containing phases, that can be associated with apatitic calcium‐phosphates Ca_10‐x(PO₄)_6‐x(HPO₄ or CO₃)_x(OH or ½ CO₃)_2‐x with 0 ≤ x ≤ 2 (Ap‐CaP), promoted in the presence of Ca²⁺ generates an effective local pH buffering system at the surface. Thus, high alkalinization is prevented, and the interface pH is stabilized in the range of 7.6 to 8.5.