Advertising claims and the ASA
How advertising rules apply to aesthetic claims, the substantiation requirement, and why a claim that cannot be evidenced should not be made.
UK advertising is governed by codes administered through the Advertising Standards Authority and written by the Committees of Advertising Practice. The central requirement is substantiation: an advertiser must hold documentary evidence for objective claims before making them, and must be able to produce it.
This matters in a field where most claims are mechanistic and most evidence is laboratory work. A mechanism observed in cell culture is not substantiation for a claim about what will happen to a person's skin, and advertising rules do not treat it as such. There are also specific restrictions on advertising prescription-only medicines to the public.
The substantiation rule
The advertising codes require that objective claims be capable of substantiation, and that the advertiser hold the evidence before the claim is made. The burden sits with the advertiser, not with the complainant, and the standard of evidence expected rises with the strength of the claim and with the potential for harm.
Two consequences follow that are frequently missed in this sector.
First, a claim is not made acceptable by being widely repeated. Every advertiser is responsible for their own claims and must hold their own evidence. Copying a supplier's marketing does not transfer the supplier's evidence, if any exists.
Second, a mechanism is not an outcome. Evidence that a preparation changes gene expression in cultured fibroblasts does not substantiate a claim that it will improve a person's skin. Those are different propositions with different evidence requirements, a distinction developed throughout our evidence section.
Health claims and the higher bar
Claims relating to health carry a higher evidential expectation than claims about appearance, and the codes contain specific rules for advertising relating to medicines, medical devices and health-related products and treatments. Where a claim implies treatment of a condition, it is no longer a cosmetic claim, which connects directly to the presentation limb discussed in borderline products and the MHRA.
There is also a separate statutory prohibition on advertising prescription-only medicines to the public. That is a matter of medicines law rather than of the advertising codes, and it is one of the areas where aesthetic advertising most often goes wrong, because named prescription treatments appear in promotional material as a matter of routine.
A clinic may advertise a treatment using the manufacturer's claims about the product.
- Proposed mechanism
- The manufacturer has substantiated the claims, so the clinic may repeat them.
- What has been shown
- Advertising rules place the substantiation burden on the advertiser making the claim. Repeating a third party's claim does not transfer that party's evidence, and a clinic must hold evidence capable of supporting the claim it makes. Where a claim relates to health or implies treatment of a condition, the expected standard is higher.
- Highest level reached
- Not shown
- Main confounders
- Suppliers frequently provide marketing material designed for repetition. Copying is easy and the burden is invisible until a complaint is made.
GradeNOT SUPPORTED
What would change thisNothing about the rule. A clinic wishing to make a claim should obtain and read the evidence for it, and decide whether it supports the specific claim in the specific wording proposed.
Before and after images
Photographic evidence is treated as a claim, and the codes address the conditions under which images may be used, including that they should not mislead. Consistency of lighting, positioning, expression, makeup and post-processing all bear on whether a pair of images misleads. In a field where the endpoint is appearance and the assessment is visual, this is not a peripheral issue.
Our position as a publication is simpler: we do not publish before and after imagery at all, because we cannot verify the conditions under which any such image was produced, and an unverifiable image is not evidence. That is a policy choice rather than a legal requirement, and it is set out in our editorial standards.
| Claim | What must be held | Common failure |
|---|---|---|
| Improves skin hydration | Evidence for the specific product and effect | Evidence for a different product or ingredient |
| Stimulates collagen production | Evidence in human skin, not only in culture | Cell culture evidence offered for a tissue claim |
| Treats acne scarring | Clinical evidence, plus a claim that engages the medicines presentation limb | No clinical evidence at all |
| Approved and clinically proven | A specific approval and specific trials, both identifiable | Neither exists in identifiable form |
Why we care about advertising rules on a science site
Because advertising is where scientific claims meet the public, and because the substantiation requirement is, in effect, a legal instantiation of the standard we apply editorially. Hold the evidence before you make the claim. State claims no stronger than the evidence supports. Be able to produce the source.
Our evidence panels do the same work in a different register. The line naming what would change our assessment is our version of holding the evidence, made visible: it states in advance what we would accept as sufficient, so that a later change of position is accountable rather than convenient.
Complaints and what follows
Anyone can complain about an advertisement, and rulings are published. That publication is the main mechanism by which sector norms shift, because a ruling against one advertiser puts every other advertiser using similar wording on notice.
For a reader, published rulings are also a useful source. They show what evidence was offered for a claim and whether it was accepted, which is a rare public window into what substantiation actually exists behind marketing language in this sector.
Questions readers ask
Who regulates advertising claims for aesthetic treatments in the UK?
Advertising is governed by codes written by the Committees of Advertising Practice and administered through the Advertising Standards Authority. Separately, medicines law restricts the advertising of prescription-only medicines to the public.
What does substantiation mean?
That the advertiser holds documentary evidence supporting an objective claim before making it, and can produce it. The burden sits on the advertiser and the expected standard rises with the strength of the claim.
Can a clinic use the manufacturer's claims?
Repeating a third party's claim does not transfer their evidence. The clinic making the claim must hold evidence capable of supporting it in the wording used.
Is cell culture evidence enough for a skin claim?
No. A mechanism observed in cultured cells is not evidence about what happens in a person's skin. They are different propositions with different evidence requirements.
Why do you not publish before and after photographs?
Because we cannot verify the conditions under which any such image was produced, and an unverifiable image is not evidence. That is our editorial policy rather than a legal requirement.