In law they are the same thing
It is worth clearing this up first, because people expect a legal distinction and there is not one to speak of.
A dedicated sun protection lotion and a day cream carrying a factor are both cosmetic products in the United Kingdom. Both are governed by the same regulation. Both must have a responsible person, a product information file and a safety assessment. If both carry a protection factor, both must have that figure supported by evidence obtained to a recognised method.
So the difference is not in the classification, not in the test method and not in the standard of evidence required. It is in what happens after the product leaves the shop.
The quantity problem
The protection factor is determined at a fixed quantity per unit area of skin, and the figure describes the product at that quantity. That is set out in the application quantity the number assumes, and it is the whole of the issue here.
A dedicated sun protection product is designed around that quantity. Its texture is formulated to be spreadable in bulk, its pack is sized for repeated generous use, and its directions tell you to apply generously and to reapply.
A moisturiser is designed around a different quantity, because a moisturiser applied at the sun protection test quantity would be an unpleasant product to use. A foundation is designed around coverage and finish. A lip product is designed around a small surface area and is removed continuously by ordinary use.
None of these is a criticism of the products. They are formulated for what they are for. The point is that the tested figure describes them at a quantity that their own design discourages.
The pattern of use
Quantity is the first difference and the pattern of use is the second.
A sun protection product is applied before exposure and reapplied through a period of exposure. That is what the directions say and it is what the product is bought for.
A moisturiser with a factor is applied once, in the morning, indoors, usually before anything else goes on top of it. A foundation is applied once and is then touched, blotted and adjusted. Neither is reapplied in the way a sun protection product is, and reapplying either over the top of the other is not straightforward.
Because the loss of protection from a thinning film is steeper than proportional, a single morning application that is not restored is a different proposition from a generous application that is.
| A dedicated sun protection product | A product with an added factor | |
|---|---|---|
| Legal classification | Cosmetic product | Cosmetic product |
| Test method for the figure | The same recognised method | The same recognised method |
| Formulated for bulk application | Yes | Generally not |
| Directions | Apply generously, reapply | A routine step |
| Circled UVA mark | Normally present | Sometimes absent |
| Pack size relative to the tested quantity | Sized for it | Rarely |
| Reapplied through exposure | Yes, by design | Rarely, and difficult over make up |
Framework of this publication. It describes how published rules and guidance fit together and is not a measurement, a survey or a study.
The UVA question
A further difference sits in what is claimed. A dedicated sun protection product sold in the United Kingdom will normally carry the circled ultraviolet A mark, indicating that ultraviolet A protection meets the recommended relationship to the labelled factor.
Products in other categories carrying a factor may or may not carry that mark. Where it is absent, no claim about the relationship has been made, and a reader has no information about ultraviolet A protection at all.
For a product used daily and year round, that is arguably a more significant gap than the quantity problem, and it is one a reader can check on the pack in a moment.
What the labelling can and cannot do
Nothing in the rules requires a product with a factor to state that it is not a substitute for a sun protection product, and no defined vocabulary distinguishes the two categories.
What the rules do require is that claims are truthful, supported and allow a consumer to make an informed decision, and that advertising is not misleading in the impression it creates. A daily moisturiser presented as delivering the protection its factor implies, without regard to how it will be used, is a presentation question rather than a formulation one.
The function statement helps, because a product must indicate its function where that is not obvious. A pack that describes itself as a moisturiser with an added factor is telling a reader something a pack that leads with the numeral is not.
Reading the two side by side
Four questions distinguish them from the pack alone. What does the function statement say the product is? Does it carry the circled ultraviolet A mark? Do the directions tell you to apply generously and reapply, or do they describe a morning routine? And is the pack sized for the quantity the figure assumes?
A product that answers all four like a sun protection product is one. A product that answers them like a moisturiser is a moisturiser with a factor, which is a real and useful thing and is not the same thing.
Formats, and where the quantity question is sharpest
Between a dedicated lotion and a moisturiser with an added factor sits a range of formats, and the quantity question applies differently to each.
A spray is applied without a clear sense of how much has landed, and some of what leaves the container does not reach skin at all. A stick covers a small area at a time and is typically used for face, ears and lips rather than for a body. A gel or a fluid formulated for a light finish is designed, like a moisturiser, to feel like less product. A mousse or an oil behaves differently again in how it spreads and how much stays put.
None of these formats is inferior as such, and the determination behind each figure was made at the same fixed quantity. What differs is how easily a user can tell whether they have applied that quantity, and formats that feel light or that disperse are the hardest to judge.
Directions on the pack usually address this in general terms, telling a user to apply generously. Where a format makes the quantity difficult to gauge, that instruction is doing more work than the same words on a thick lotion, and it is worth reading as such.
This is not an argument against them
It would be easy to read this as a case against products with an added factor, and that is not the argument.
Adding ultraviolet protection to a product somebody already uses daily is a reasonable formulation decision, and public health guidance in the United Kingdom is consistent that sun protection products form part of a set of measures rather than the whole of it. Where such a product is used, it is used.
What this publication objects to is not the product. It is a label that lets a figure obtained under one set of conditions be read as though the conditions were the same.
Where the categories blur deliberately
Between a clear sun protection product and a clear moisturiser with an added factor sits a band of products designed to occupy both positions at once, and the labelling reflects that ambition rather than resolving it.
Such a product may lead with a large numeral like a sunscreen, carry the circled ultraviolet A mark like a sunscreen, and describe itself in language borrowed from skincare, with a texture and a pack size that belong to the latter. Nothing about that is non-compliant. Each element is supportable and the combination is a commercial position.
What it does is leave the reader to determine which set of expectations applies, using cues that have been deliberately balanced. The function statement is the element that resolves it, which is why it sits first in the reading order set out in how to read a sun protection label in order, and why it is worth looking for before the numeral.
What to take from this
Same classification, same test method, same evidence standard, entirely different use. The figure describes both at a quantity that only one of them is designed for, and the circled ultraviolet A mark is the quickest way to see which is which.