"All soaps have been tested by me" but how?
It's quite easy to get by, at least initially, by trialling on yourself. I know I've done it in work, but as we're fulfilling orders of the product in 100,000's, it
does get microbial limits tested/challenge tested as well as accelerated shelf-life tested and period after opening (PAO) tested if required. All ingredients have to be cosmetics grade minimum and I have to raise an MSDS for the product, COSHH forms for each ingredient used, product information file etc. The initial testing on myself is for new product development for specific military tenders. If I have no adverse reactions, nor do 5 of my colleagues (who are warned about the potential for unfavourable reactions and have their names logged and signed) then it's submitted to the tender on that basis. If said tender likes what they receive, then away to go with further testing.
If the testing at the moment is simply that he's tried it on himself, or that he has scope to do some shelf-life testing at home (with the correct equipment) then that's up to user discretion whether or not they buy/use it. If it becomes more domesticated, such that people who (a) don't know what's in it and/or (b) don't know what it's used for end up buying it, then there could be issues down the line.
Fortunately, cosmetics testing isn't expensive if you look around. Shelf-life testing only needs to be done for a 30-month period for domestic sales (anything more is overkill and you'd need a PAO test thereafter). Companies who do both of these may even submit the seller to the cosmetics suppliers database though I'm not sure of the intricacies of that, personally.
I'd
assume that James will have done his research prior to making any of the products he does, especially as they're highly regarded on here from what I can see! Soap making is a well-documented skill so being short of literature isn't an option. I'd imagine it's one particular component of one particular ingredient that has a greater chance of triggering an allergic reaction in the Shogun variant. I'd like to try it myself and see whether I exhibit a rash/burning/stinging of any sort - I'm fortunate to have quite resilient skin!
Hope this helps! Sorry again for the ramblings, I enjoy chemistry and all that's with it...except chemical warfare, obviously.