Ad description

A regional press ad for a horse supplement stated "ProKalm SCIENTIFICALLY PROVEN To reduce anxiety and nervousness Rapid acting / Aids concentration Does not effect [sic] gait for performance Dose can be varied for required effect The natural choice for trainers contains no banned substances".


The complainant challenged whether the claims "Scientifically proven to reduce anxiety and nervousness" and "aids concentration" were misleading and could be substantiated.


Horse Requisites Newmarket Ltd (Horse Requisites) provided a dissertation which included a double blinded placebo controlled study which examined the effect of ProKalm on 16 horses, which they believed substantiated the claims in the ad.



While evidence was not presented to demonstrate that the study had been published in a peer-reviewed journal, the ASA examined the dissertation which contained the study. We took expert advice in relation to the submitted evidence. The expert advised that although the study had the potential to support claims that the product could aid concentration, it was not sufficiently robust to support claims in the ad which related to the effect on equine behaviour.

The study was based on 16 horses that underwent a novel object test and temperament assessment prior to and following seven days of receiving the active product or a placebo. With regard to the design of the study, our expert was concerned that it did not detail the formulation of the active product or placebo and that bias had not been ruled out with regard to the selection of the horses included in the study and that it was entirely possible that the selected horses were of a non-nervous disposition (and therefore not the horses which were likely to be the subject of the ad). The expert stated that the small number of subjects and the study's design severely limited the power to demonstrate the true effect of the product and that it went some way to explain the inconsistencies in the results. With regard to the desirable traits it was noted there was no difference in overall scores for the active product or placebo but that for undesirable traits there was a significant reduction in scores for horses on the placebo only, which suggested that the placebo had worked better than the active substance at reducing undesirable behaviours. It was also noted 'nervousness', 'skittishness' and 'timidity' scores had significantly reduced in the placebo group between days 0 and 7 which again suggested that the placebo was more effective.

Whilst the expert noted concentration scores had increased with the active product, we considered that because previous concerns had been raised about the design of the trial and the number of test subjects (and how those subjects were chosen) any results were unlikely to have been obtained under conditions which were sufficiently robust for the purpose of substantiating the advertising claims. Furthermore, the dissertation in which the study was contained stated that the results were inconclusive with regard to the efficacy of the calming product on equine behaviour.

We considered that the evidence was not sufficiently robust to support the claims that ProKalm was "Scientifically proven to reduce anxiety and nervousness" or "aid concentration" in horses and therefore concluded that the ad was misleading.

The ad breached CAP Code (Edition 12) rules  3.1 3.1 Marketing communications must not materially mislead or be likely to do so.  (Misleading advertising),  3.7 3.7 Before distributing or submitting a marketing communication for publication, marketers must hold documentary evidence to prove claims that consumers are likely to regard as objective and that are capable of objective substantiation. The ASA may regard claims as misleading in the absence of adequate substantiation.  (Substantiation) and  12.1 12.1 Objective claims must be backed by evidence, if relevant consisting of trials conducted on people. 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, VMD or under the auspices of the EMA, 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 defined 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.
 (Medicines, medical devices, health-related products and beauty products).


The ad must not appear again in its current form. We told Horse Requisites to ensure it held robust evidence before making future efficacy claims for the product.

CAP Code (Edition 12)

12.1     3.1     3.7    

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