What breaks it
On this page9
Moisturising
The commonest one, because it is true of a superfatted soap and because it is what the customer wants to hear. It is also a claim about what the product does beyond cleaning.
Named conditions
For eczema, for acne, for psoriasis. These are not cosmetic claims at all; they are claims to treat a disease, which is a drug claim and a much bigger step than losing a cosmetic exemption.
Anti-bacterial and sanitising
A claim about killing organisms. It takes the product out of the exemption and into a regime that requires approval rather than labeling.
Deodorising
Addressing body odour is a cosmetic purpose, so a soap claiming it is representing itself as more than soap. The deodorant property covers what follows if the claim moves further.
Where these appear
Rarely on the wrapper. Usually in the online listing, the Instagram caption, the market stall sign and the answer given to a customer who asked what it is good for.
Which means the whole presentation counts
As everywhere in this library, intended use is read from everything a buyer sees. A compliant wrapper attached to a listing full of claims is not a compliant product.
The fix is not silence
A soap can be described richly: the oils, the scent, how it lathers, how it is made, how long it cured. All of that sells and none of it is a claim about what the product does to a person.
And the fallback is simply to comply
Cosmetic labeling for a bar of soap is an ingredient list, a net weight and an address. If the claim matters commercially, the honest route is to make the claim and label as a cosmetic rather than to make it quietly.