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.
Also known as: customer reviews, testimonials, evidence, substantiation, subjective opinion
This guidance deals with claims made within testimonials. For the rules on using testimonials in marketing communications, and evidencing that they are genuine, please see “Testimonials and Endorsements”.
Hold evidence for objective claims
Testimonials must relate to the product advertised and claims in a testimonial that are likely to be interpreted as factual must not mislead or be likely to mislead the consumer (rules 3.46 and 3.47). The Code applies to claims made in testimonials in the same way that they apply to claims elsewhere in advertising. Unless they are clearly subjective, marketers must hold evidence for all claims made in testimonials. When making health, or medicinal claims, additional rules will apply.
Hold evidence for objective claims
Any objective claims made in testimonials, such as those about the efficacy of a product, must be supported by sufficient objective evidence to support the claim.
A testimonial which stated “My mum is diabetic […] Frank's is the only ice cream she can have, in fact it's the only dessert at all she can have” was considered problematic. The ASA understood that people with diabetes were able to consume all types of food, including ice-cream, within the context of a healthy and balanced diet, and that specialist foods were not necessary. Because the claim implied that the ice cream was suitable for diabetics because it had special characteristics, and that no similar foods were suitable for diabetics when that was not the case, the ad was considered misleading (Frank’s Ice Cream Ltd, 29 March 2023).
Similarly, a testimonial in an ad for a natural deodorant was considered to allude to the common misconception that traditional deodorants containing ingredients such as aluminium, and which were seen as less “natural”, were linked to breast cancer. On that basis, the ASA expected evidence to show that traditional deodorants had a negative impact on health, including a risk of breast cancer, and that the advertised deodorant was safer. In the absence of such evidence, the ad was deemed to be misleading (Wild Cosmetics Ltd, 24 July 2024). See also Hamilton Direct Ltd, 27 September 2023 and Prime Star Shop Ltd t/a Branshaws, 16 August 2023.
An ad for a law firm specialising in financial claims, which included testimonials, was found to have breached rule 3.47. The testimonials from individuals claiming to have received cheque for a certain sum were not from genuine customers, and so were considered misleading (TMS Legal Ltd, 15 November 2023). See also Simmer Ltd, 17 July 2024 and Water for Health Ltd, 3 July 2013.
Although some testimonials often feature the views of the person who gave it, if those views can also be understood to be efficacy claims, then they should not be included in advertising, unless supported by sufficient evidence. A testimonial stated "... these products really work and if you compare with the price of plastic surgery you'll see that they are not expensive at all ..." While the ASA acknowledged that the testimonial might have been a genuinely held opinion, it was also an objective claim. Because the ASA were not provided with objective evidence to show that body sculpture was an effective alternative to surgery, the testimonial was considered problematic (Rodial Ltd, 11 January 2012).
Similarly, a website selling pellets to add to a vehicle’s fuel tank included customer reviews, one of which described a customer’s positive experience with using the pellets to restore performance. The ASA made clear the claims were objective claims that required robust substantiation based on independent testing (Hamilton Direct Ltd, 27 September 2023).
See Types of claims: Puffery and expressions of opinion for advice on how to effectively present opinions in ads.
Health or medicinal claims
Section 15 of the CAP Code sets out the rules which specifically relate to marketing communications concerning food, food supplements and associated health or nutrition claims. These rules apply to any claims made in in testimonials used in advertising. See ‘Food: health and nutrition general’ for details.
Section 12 of the CAP Code sets out the rules that apply to marketing communications for medicines, medical devices, health related products and beauty products. CAP has written several AdviceOnline library entries on the topic of healthcare. See ‘Healthcare: overview’ for details.
Ads for water filters which made multiple claims to treat acid reflux, including claims in testimonials which promoted the cessation of acid reflux medication, were deemed to have breached the CAP Code. This was because they were not supported by evidence, and because they discouraged the essential treatment of health conditions for which medical supervision should be sought, contrary to rule 12.2 (Phox Water Ltd, 2 November 2022).
Testimonials are not evidence
Testimonials alone do not constitute substantiation so marketers should not rely on testimonials as support for any direct or implied claims made in the marketing communication.
Customer survey responses which made positive comments about saving money on energy bills were not considered adequate substantiation for savings claims (Bright Networks Ltd t/a Bright Heating, 9 January 2013). In July 2023, the ASA made clear that emails from two clients were not adequate evidence to substantiate claims about the efficacy of treatments (Lipstick Gangster Ltd t/a The Lipstick Gangster, 12 July 2023) See also Halcyon Bracelets, 18 February 2015).
See Substantiation for more information on evidential requirements more generally.