Summary of Council decision:

Two issues were investigated, both of which were Upheld.

Ad description

A website for Phox Water, a water filter company, seen on 11 June 2022.

On a webpage with the heading “PHOX COMPATIBLE”, there was an image of two Phox Water refill products. Under the second refill product, text stated, “ALKALINE PACK” “[tick] HELPS ACID REFLUX [tick]

Further text stated, “WHY THE ALKALINE PACK?”. Underneath that, text stated, “SOOTHES ACID REFLUX Alkaline water can be an effective remedy for acid reflux. A study by Kaufman and Johnson (2012) found alkaline water inactivated human pepsin due to its acid-buffering capacity”.

Three testimonials were also included on the website. Text in the first testimonial stated, “Have to admit to being a bit cynical. Got the alkaline pack as I suffer from Acid Reflux. I now don’t need the reflux medication, and overall find myself recovering quicker from heavy gym sessions. K Parker”. The second testimonial stated, “Fantastic product! […] I went for the alkaline option and it has really helped with my reflux issues. Melanie”. The final testimonial stated, “I’ve been using Phox water jug and alkaline refills for a couple of years now […] The alkaline filtration is good for my stomach. Sabrina”.


The complainant challenged whether:

1. the claims that the Phox Water Alkaline Filter product could treat acid reflux were misleading and could be substantiated; and

2. the ad discouraged essential treatment for acid reflux which was a symptom of health conditions for which medical supervision should be sought.


1. & 2. Phox Water Ltd emphasised the company was founded because of how effective alkaline water had been in helping the owner overcome his symptoms of acid reflux.

They provided an abstract for one study and a clinical trial in full, which they said supported the claim that alkaline water could treat acid reflux. They said that the clinical trial found that there was no significant difference in reflux symptom index reduction between patients who were treated with alkaline water, a plant-based Mediterranean-style diet and standard reflux precautions compared to those who were treated with proton pump inhibitors and standard reflux precautions. They also submitted reviews from their own TrustPilot webpage.

Finally, they stated that their intention was not to compare their product to medication, nor would they urge anyone to avoid medical advice. As such, they confirmed that reviews from the website that referenced no longer needing medication had been removed.


1. Upheld

The ASA understood that alkaline water (water with a pH greater than 7) was able to temporarily neutralise pepsin, a digestive enzyme, which was thought to contribute to acid reflux. However, we understood that there was little scientific evidence to prove that alkaline water could neutralise acid in the stomach, and therefore, prevent acid reflux.

As such, in order to substantiate the claims, we considered that a substantive body of evidence was needed, consisting of clinical trials conducted on humans. However, when we assessed the evidence provided by Phox Water, we considered that it did not meet the standard of evidence we required for the type of claims being made.

They provided an abstract which summarised an in vitro study that determined whether alkaline water with pH 8.8 inactivated human pepsin. We were not provided with a full copy of the study and did not consider that the abstract on its own was adequate to act as substantiation for the claim. In any case, as it assessed the effects of alkaline water on pepsin under laboratory conditions, and was not a clinical trial conducted on humans, it was not sufficient to support claims about the product’s affect in treating acid reflux.

They also provided a clinical trial in full. The trial assessed the effectiveness of a diet-based approach (alkaline water and a plant-based, Mediterranean-style diet) with standard reflux precautions compared to proton pump inhibitors (medication that reduced the amount of acid produced by the stomach) with standard reflux precautions for six weeks in 184 patients with laryngopharyngeal reflux (LPR). We noted that the individual effects of alkaline water on acid reflux symptoms were not investigated in the study. Notwithstanding that, we had concerns about the methodology used in the study. There was no blinding of the participants involved in the study and they had not been randomly allocated to receive either the diet-based approach or the proton pump inhibitor. The outcomes that were assessed were based on self-reported, subjective measures. Given that the participants were not blinded to the treatment, we considered that this could influence the results. Moreover, those who took part in the study were diagnosed with laryngopharyngeal reflux (LPR), which we understood to be only one type of acid reflux. In addition, the paper concluded that further research, including from randomised clinical trials, was required to determine the clinical significance of the study’s results. For those reasons, we did not consider that it was sufficient to substantiate the claim.

The final submission was a set of reviews originating from Phox Water’s TrustPilot webpage that referred to acid reflux. Whilst there were positive reviews, we did not consider testimonials alone sufficient to substantiate objective efficacy claims.

Because we had not seen sufficient evidence that the Phox Water alkaline filtration system could treat or soothe acid reflux, we concluded that the claims had not been substantiated and were therefore misleading.

On that point, the ad breached CAP (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).

2. Upheld

The ASA understood that chronic acid reflux could be a symptom of serious underlying conditions including stomach ulcers and cancers, which were conditions for which medical supervision should be sought. We acknowledged that acid reflux could also be a symptom of less serious conditions such as heartburn.

The ad stated that the alkaline water filtration system “soothes acid reflux” and that it was an “effective remedy” to acid reflux. In particular, we considered that the term “remedy” would be interpreted as having a curative or corrective function. The ad also included a testimonial which referred to discontinuing acid reflux medication and using the water filtration system in its place. We considered that consumers would interpret these as references to chronic acid reflux and that the water filtration system was effective in treating acid reflux on a long-term basis. That interpretation was also reinforced by the product itself. We considered that given the nature of a water filtration system, it was unlikely that consumers would purchase the product for single or short-term use. This was further highlighted by two further testimonials included in the ad which referenced using the filter on a long-term basis.

We therefore considered that by marketing the product as a treatment for chronic acid reflux and including a testimonial which promoted the cessation of acid reflux medication, the ad discouraged essential treatment for the condition. Because of that implication, we considered consumers who were experiencing persistent acid reflux, and whose symptoms could be the result of a serious condition, would be less likely to seek medical advice promptly, about their symptoms. Furthermore, because the treatment offered by the product did not take place under the supervision of a suitably qualified health professional, we concluded that the claims breached the Code.

On that point, the ad breached CAP Code (Edition 12) rule  12.2 12.2 Marketers must not discourage essential treatment for conditions for which medical supervision should be sought. For example, they must not offer specific advice on, diagnosis of or treatment for such conditions unless that advice, diagnosis or treatment is conducted under the supervision of a suitably qualified health professional. Accurate and responsible general information about such conditions may, however, be offered (see rule 12.11).
Health professionals will be deemed suitably qualified only if they can provide suitable credentials, for example, evidence of: relevant professional expertise or qualifications; systems for regular review of members' skills and competencies and suitable professional indemnity insurance covering all services provided; accreditation by a professional or regulatory body that has systems for dealing with complaints and taking disciplinary action and has registration based on minimum standards for training and qualifications.
 (Medicines, medical devices, health-related products and beauty products).


The ad must not appear again in its current form. We told Phox Water Ltd not to make claims that their alkaline water filtration system could alleviate acid reflux in the absence of adequate substantiation, or to discourage essential treatment for health conditions for which medical supervision should be sought.

CAP Code (Edition 12)

3.1     3.7     12.1     12.2    

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