Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.


One of the main tenets of the Codes is that the burden of proof for claims lies with advertisers. Before submitting an advertisement for publication, advertisers must hold documentary evidence to prove claims that consumers are likely to regard as objective and that are capable of objective substantiation (Rule 3.7).

Advertisers of health, beauty and slimming products should pay particular attention to the requirements of the Codes' specific rules on health and beauty products and therapies, particularly rule 12.1 which states "Objective claims must be backed by evidence, if relevant consisting of trials conducted on people. If relevant, the rules in this section apply to claims for products for animals.  Substantiation will be assessed on the basis of the available scientific knowledge.  Medicinal or medical claims and indications may be made for a medicinal product that is licensed by the MHRA or EMEA, or for a CE-marked medical device. A medicinal claim is a claim that a product or its constituent(s) can be used with a view to making a medical diagnosis or can treat or prevent disease, including an injury, ailment or adverse condition, whether of body or mind, in human beings.  Secondary medicinal claims made for cosmetic products as defi ned in the appropriate European legislation must be backed by evidence. These are limited to any preventative action of the product and may not include claims to treat disease".  Please also note rules 13.1/13.5/13.6 which detail evidence requirements for slimming claims.

In July 1998, with input from the Health and Beauty Working Group, CAP produced a Help Note on Substantiation which provides detailed guidance on the type and volume of data that the ASA and CAP expects advertisers to hold to back up a variety of different categories of claims.

The Help Note identifies three types of health, beauty and slimming claims that are made for products (or services):

sensory/impressionistic subjective claims - these are claims that cannot be proved objectively and which might be understood to be opinion e.g. "no other shower gel leaves you feeling fresher". In some circumstances, satisfactory consumer research may be required to back them up (see Section 1 of the Help Note);

uncontroversial/established objective claims - a less significant amount of evidence is usually needed in support of these types of claims. The Help Note gives examples of what might constitute satisfactory proof (see Section 2);

"New" or "breakthrough" objective claims - the ASA and CAP have more stringent evidence requirements for these types of claims. Sound data, relevant to the claim made, should be collated to form a body of evidence. This should normally include: at least one experimental human study (ideally double-blind and placebo-controlled) and often observational human studies. The Help Note details other categories of evidence that might form part of a body of evidence and gives specific guidance on the quality of data, including the importance of the studies being subjected to peer-review either through publication in reputable, peer-reviewed journals or assessment by an independent expert (see Section 3)

The CAP Copy Advice team is happy to consider whether an advertisers'' substantiation is likely to be sufficient and will, where the necessary, seek advice from an expert consultant. The team urges advertisers to follow the guidance in the Help Note when compiling substantiation for health, beauty and slimming claims.

See also entries on: "References to Ailments", "Substantiation", "Matters of Opinion", "Testimonials and Endorsements"


More on