*3.1. Elemental Characterisation of Pristine Materials*

Elemental composition of pristine components (PS9, G30 and ALI) is reported in Table 1. According to the EC 1272/2008, any of the detected elements are not considered as carcinogens.

Major elements in the pristine water (ALI) were Sr, S, Ca, Mg and Na (from higher to lower concentrations). The high presence of S, Ca and Mg are in agreement with the nature of the spring water source [34,35]. Ti, Mn, Mg, Sr, Zn and Al are the major elements present in PS9 and G30. In particular, Zn, Mn, Mg and Al belong to class 4 in the Q3D(R1) guideline [32]. Regarding the cosmetic regulation EC 1223/2009 [33], aluminum is the only one specifically allowed in cosmetics, the rest of them are not mentioned in this regulation. Cu and Ag are elements present in the pristine ingredients that have a "special situation" as far as regulation is concerned, since their presence is allowed in cosmetics (mainly due to their role as colorants) but they are classified as class 3 and 2B by the Q3D(R1).


**Table 1.** Elemental composition of pristine samples (PS9, G30 and ALI) determined by ICP-OES and ICP-MS. "ND" stands for "Not Detected". For a better understanding, comments about each element are included within the table. Levels of elements marked with \* were obtained from [36].
