Or… “tanning”… not to be confused with skin darkening from ultaviolet exposure, I mean tanning in the sense of converting a raw skin into leather… appears that this process is part of why skin gets old and … leathery…
OK… got my hands on a commercial bath water additive based on a chelation agent, EDTA, which has a powerful binding affinity for heavy metals and ferro metals… and it also seems that the gradual exposure of the skin to these metal ions allow them to bind with the skin’s collagen structure and cause cross linkage… cross lining toughens a hide and that’s basically what makes leather different from a raw animal skin… the more cross linked the skin collagen, the better it’s wearing properties, and the tougher it feels…
Sooooo… I thought… maybe there’s some truth to this assertion that we are gradually tanning ourselves by the free metal ions in our bath and shower water…
Last night… took a large scoop, 1/4 cup of CaNa2EDTA and poured it into the bath… dissolved immediately before it touched bottom, swished it around.. the water did feel noticably wetter, i.e. the surface tension was reduced, and lower surface tension will also mean soaps will clean more deeply…
Took long bath… rinsed off with tap water… and… begorrah !.. my skin did have a slightly silkier, more elastic feel and it had a nice tingly clean quality upon going to bed… nothing drastic… maybe after two or three baths the effect is more pronounced…
For now, my very tentative conclusion is that bathwater (and the tap water you drink unless well filetered) IS bearing some degree of dissolved metal ion which do migrate into the skin’s collagen and alter it…