Claims about a product of service should always contain the evidence, or a link to the evidence, for such claim. This allows the consumer to objectively evaluate the claim and to not include such evidence can constitute misleading or deceptive advertising.

So for example:

UNACCEPTABLE: Freedom Hand Soap provides 99.9% protection against germs  

ACCEPTABLE: Freedom Hand Soap provides 99.9% protection against germs (see evidence for this at https://www.freedomsoap.co.za/evidence)