The term hypoallergenic, which you can find on the label of a cosmetic product, suggests that that certain product has little to no risk of allergic reactions. The term is not legally defined and therefore free for use. The term does not provide any guarantee for people with allergies. A so-called "list of ingredients" is a much more reliable guarantee. Consumers who are aware of their allergic reactions to certain ingredients can, based on the legal compulsory listing of ingredients on the product, decide for the products that are most suitable to them.
Dermatologically tested means that the manufacturer had the product tested on volunteers by dermatologists. The term does not indicate the result of the test. Nothing is legally defined concerning the size of the group of volunteers or the quality of the research. Meaning that the term dermatologically tested has no legal content and can be used freely.
With the term PH neutral it is indicated that the product possesses an acidity, which is close to the acidity of the skin. The term is seen a lot on soap, bath and shower products. For the tolerability of these products other factors play a more important role than the PH value. It is for example important what soap or fragrance is used; PH neutral does not reveal anything about these factors.
Although most of the products, which are claimed to have a natural basis, are not even produced on "natural basis", there are some exceptions of products which are in fact based on a natural basis. However, this term has no valuable meaning. What is the benefit for example to make a product with a natural main ingredient, in order to fill it with synthetic substances afterwards? The term 100% natural is certainly a valuable reference.
Rare products methods
There are for example soaps, which are produced from Extra Virgin olive oil (first cold pressing). During the process, the oil is cooked from eight to 40 hours. It is very well likely that many significant features of the high quality oil get lost during this process. The only question that remains is ... was it Extra Virgin in the first place?