In another discussion someone asked whether they should include Panthenol in their shampoo formula. I know this ingredient is used in a number of different hair care brands, but I've always just assumed it was for claims purposes. That's because when I tested formulas with and without the ingredient no one could tell a difference.
This with/without test has always been my gold standard for determining whether an ingredient was effective or just a claims ingredient. Results from lab tests, supplier data, other literature or theoretical notions guide whether to investigate a material. However, if I put something in a formula and consumers don't notice any difference, I conclude that it doesn't provide a benefit.
Am I too skeptical?
What convinces you that an ingredient provides a benefit? For example, what convinces you that Aloe has any significant benefit in a formula beyond making claims?