(This post was last modified: 08-27-2018, 04:26 AM by yohannrjm.)
(08-27-2018, 04:02 AM)Marko Wrote: I suppose someone could get scientific about it if they're having problems with certain soaps that contain lanolin - you could list all of the ingredients of every soap you have including the ones that cause a reaction or irritation and then cross reference the ingredients to see if there is a common ingredient in the irritating soaps that isn't in the non-irritating soaps. It might be a problem if some ingredients are referred to generically such as "fragrance oil" or "essential oil" because not all fragrance/essential oils will be chemically the same and some could cause a reaction and others not. You'd need to know which oils were used for this experiment to work.
Not only that, but the way these items are combined would also affect the way they would affect someone's skin. It's a very complex system and the answer can sometimes be as simple as a common ingredient and sometimes it can be a very complex combination of factors. It's certainly possible to work out what exactly in a product is causing an issue, but the process can be long and involved and not always worth the effort.
And these being artisan soaps, there's no guarantee that your conclusion (however well correlated) will hold true for the next batch of soap.
EDIT: One of the issues that may be caused by the addition of a common ingredient like lanolin is incomplete conversion of lye + oil into soap, leaving some leftover lye (which people are sensitive to) or oil.
One easy way to see if it is lanolin that the OP is sensitive to is to get lanolin itself (it is available in lip balms and by itself as a skin care product) and apply it and see what happens.
- Yohann