Can you call your oil non-comedogenic on a UK label?

Can you call your oil non-comedogenic on a UK label?

You have the chart open on your phone. Somebody's comedogenic ratings list, the one that gets reposted every few weeks, and next to your oil there is a 0. Which is exactly what you were hoping for, because the labels are being printed this week and "non-comedogenic" would look very good on the front of that face oil.

The short answer is no — not from that chart, and not for a finished product you have not tested. The longer answer is more useful, because it tells you what you can write, and it turns out to be quite a lot.

The chart is not a fabrication. Those numbers were measured. They were measured on the inside of rabbits' ears, at a fixed 10% dilution, on raw materials rather than on anybody's face cream — and that gap between what was measured and what people think it says is the whole subject here.

The oils themselves are sorted by chemistry in plant oils by fatty-acid group; this piece is about the sentences that end up on the carton.

Below: the five claims that stick most stubbornly to plant oils — "non-comedogenic", "like your skin's own sebum", "dry oil", "nourishing" and "penetrates deeply" — and for each one, where the claim meets a measurement someone actually made, and what a UK brand can defensibly print. Nothing here is legal advice. And because this is an article about wording, problematic phrases appear in quotation marks as examples of wording, never as assertions about a material.

Where the comedogenic ratings come from

Comedogenic means able to promote comedones — the plugged follicles that surface as blackheads and whiteheads. Most published ingredient ratings trace back to rabbit-ear assays, including James Fulton's 1989 survey in the Journal of the Society of Cosmetic Chemists (40(6), 321–333). Here is the entire apparatus behind a number people quote as though it were an intrinsic property of an oil:

• test materials mixed in propylene glycol at a 9:1 dilution — that is, 10%, never neat;
• 1 ml applied daily to the inner surface of one ear, the opposite ear kept as an untreated control;
• five days a week for two weeks;
• three New Zealand albino rabbits, 2–3 kg, per assay;
• follicular keratosis and surface irritancy each graded 0 to 5 — 0 to 1 minimal, 2 to 3 borderline, 4 to 5 positive and, in Fulton's words, uniformly reproducible.

Three rabbits. Ten per cent. Two weeks. That is a screening tool for a raw material, and as a screening tool it works: it tells a formulator which materials deserve a closer look before they go into a leave-on product for someone prone to breakouts.

What to do with it: use a grade to decide what to test and in what order — the grades that cause the most argument are the ones attached to coconut and the other lauric oils, and they are grades of the raw material at 10%, like all the rest. Do not move a grade onto your carton.

What the human data says about the rabbit data

The human assay came first, seven years before Fulton's survey. Mills and Kligman described it in Archives of Dermatology (1982): substances applied under occlusion for one month to the upper back of young adult men with large follicles, with follicular hyperkeratosis — a build-up of keratin inside the follicle — assessed by a non-invasive "follicular biopsy" — a fast-setting cyanoacrylate glue used to lift out the follicular contents.

Two of their conclusions matter more than the assay itself, and they are the calibration between the two models, written by the people who built them:

The rabbit model is more sensitive than the human.

Substances that are weakly comedogenic in the rabbit are probably safe for human use with the possible exception of acne-prone persons.

Then Draelos and DiNardo asked the question that breaks the list (Journal of the American Academy of Dermatology, 2006). Using a modification of the Mills and Kligman assay on six individuals with prominent follicular orifices and the ability to form comedones on the upper back, each receiving patches saturated with 0.2 to 0.5 ml of finished cosmetic products, three times weekly for four weeks, with cyanoacrylate biopsies counting follicles and microcomedones per square inch, they concluded:

Finished products using comedogenic ingredients are not necessarily comedogenic.

Their own stated limitation is that only a finite number of finished cosmetic products could be analysed.

Put the three together and the position is not "the lists are wrong". It is narrower and more awkward than that.

A universal non-comedogenic oils list is not defensible, and the reason is structural rather than a matter of better data arriving later. Comedogenicity as measured is a property of a tested preparation at a tested concentration on tested skin — and an oil is not a preparation.

Note the silence in the other direction too. None of this work establishes that any particular oil is problematic in a finished cosmetic. It establishes that the ingredient grade does not answer the question either way.

What to do with it: if you want the claim on the product, the test is on the product. If that is out of budget this year, the sentence comes off the label and the grade stays in your development notes.

"Like your skin's own sebum": the one that is half true

Two materials attract this claim — jojoba and squalane — and in both cases something real sits underneath it while the popular version overshoots.

Human sebum does contain lipid classes found nowhere else on the body. Picardo, Ottaviani, Camera and Mastrofrancesco (Dermato-endocrinology, 2009) state that human sebum contains unique lipids, such as squalene and wax esters, not found anywhere else in the body nor among the epidermal surface lipids. Smith and Thiboutot (Journal of Lipid Research, 2008) make the same point from the gland's side: of the lipids the sebaceous gland produces, two are characteristic of it — wax esters and squalene.

Gad and colleagues (Polymers, 2021) describe jojoba as ranking among the top oils because of its wax, which constitutes about 98% — mainly wax esters, with few free fatty acids, alcohols and hydrocarbons. So the class statement is sound: jojoba consists predominantly of wax esters, and wax esters are a lipid class also present in human sebum.

What does not follow is that they are the same wax esters. Chain lengths, branching and double-bond positions differ. "Contains the same class of lipid" and "is the same material" are two different sentences, and only the first one is true.

Squalane runs the same way with one extra step. Sebum's characteristic hydrocarbon in both papers above is squalene; squalane is the fully saturated form of that molecule. That is a statement about nomenclature and structure, not a measurement — squalane is a relative of a sebum component rather than the component itself.

What to do with it: name the class and stop. "A wax ester, as the skin's surface lipids include wax esters." "A saturated relative of a lipid the sebaceous gland makes." Less exciting than "identical to your skin's own oil", and true — which is the point when the honesty criterion below gets applied to it.

"Dry oil", "nourishing", "penetrates deeply"

"Dry oil" is a sensory description with no standardised analytical endpoint behind it. A brand using it should be able to say what after-feel it means and substantiate that. Our own view: keep it as trade shorthand between formulators. On a pack it invites the buyer to read it as a property you cannot measure. How the underlying feel is measured — spreading value, polarity, panels — is in why one oil feels light and another feels heavy and why your cream feels greasy.

"Nourishing" is the vaguest of the three and the one most often assumed to be safe for exactly that reason. It is not. It implies a benefit, and once a reader takes it as a benefit rather than as obvious hyperbole, it needs support like any other objective claim.

"Penetrates deeply" is the interesting one, because it has been measured — and the measurement does not say what the phrase implies.

Choe, Schleusener, Lademann and Darvin (Journal of Dermatological Science, 2017) used in vivo confocal Raman microscopy to follow mineral-derived oils (paraffin and petrolatum) and plant-derived oils (almond and jojoba) into the human stratum corneum — the outermost layer of skin, the dead-cell layer you actually touch. Their finding: all the oils remain in the upper layers of it, 0 to 20% of its thickness, where plant-derived oils produced more disordered lateral and lamellar packing of the intercellular lipids — the lipids that sit between those cells and hold the layer together — than intact skin (p<0.05). Changes at 30% and at 70–90% of thickness they attribute, as a likely explanation, to penetration of free fatty acid fractions into deeper layers — a proposed mechanism in their own paper, not demonstrated transport of the oil itself.

Stamatas and colleagues (Journal of Dermatological Science, 2008) reached a compatible result by the same technique on nine adult volunteers and seven infants, measuring before and at 30 and 90 minutes after application. Paraffin oil and two vegetable oils penetrated the top layers of the stratum corneum with similar concentration profiles in adults and infants alike, and all three produced modest swelling of 10–20% against 40–60% for petrolatum as a positive control. Their conclusion: no statistical difference between the paraffin oil and the vegetable oils in terms of skin penetration and skin occlusion.

Two consequences for the label. Broader penetration wording would need product-specific evidence — and, since claiming an effect below the surface starts to look like a claim about physiology, a separate assessment of whether the product is still a cosmetic at all. And in the one comparison that was run, the vegetable oils were not distinguishable from mineral oil on either measure.

Both studies used specific oils — almond, jojoba, two unnamed vegetable oils — and neither licenses a statement about plant oils as a class. Where a specific oil has not been studied this way, the honest position is that we do not know.

What to do with it: drop "penetrates deeply" entirely. If you want to say something in that space, say what was measured: an oil that stays in the outermost layers and changes how they sit is doing something real, and describing it accurately costs you nothing.

A word on tradition, since it is often offered as evidence

Treating traditional oil use as folklore to be swept aside is a mistake. Long-standing use points at materials worth investigating — what survived tends to be stable, cheap to press locally and pleasant to use. That is a real filter.

What the filter cannot do is tell you why, because it selects on outcome under one set of conditions: one climate, one press, one storage vessel, one use pattern. Move the material into a water-containing emulsion with a preservative system and a pump dispenser and those conditions no longer hold.

What to do with it: traditional use earns an oil a place on the bench, never a sentence on the label. The evidence rules below ask for evidence relevant to the product and the benefit claimed, and "people have used it for centuries" is not that.

The two rulebooks you are actually working under

For cosmetics sold in Great Britain there are two separate systems, and they are not the same thing. One is law. The other is advertising self-regulation, and it bites faster.

The law

Article 20 of the UK Cosmetics Regulation, as it stands in retained GB law:

In the labelling, making available on the market and advertising of cosmetic products, text, names, trade marks, pictures and figurative or other signs shall not be used to imply that these products have characteristics or functions which they do not have.

And paragraph 2, as substituted for GB by the Product Safety and Metrology etc. (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/696):

A responsible person must ensure that the wording of any claim in relation to a cosmetic product is in compliance with the common criteria set out in the Annex to Commission Regulation (EU) No 655/2013.

Those common criteria are also published on legislation.gov.uk and kept up to date with UK amendments; we opened the Annex on 22 September 2026 and confirmed the retained text, including the marks showing paragraphs substituted by S.I. 2019/696. There are six criteria — legal compliance, truthfulness, evidential support, honesty, fairness and informed decision-making — and three paragraphs decide most oil claims:

Paragraph 4(2) is worth a read too: "Claims shall not attribute to the product concerned specific (i.e. unique) characteristics if similar products possess the same characteristics." A good deal of ingredient-led copy quietly fails there.

Who carries this is not vague. The CTPA, the UK industry association, puts it directly: all claims must comply with Article 20 and with Regulation 655/2013, and "it is the Responsible Person placing the cosmetic products on the market that is responsible for any claims made, including the claims substantiation."

And under the government's guidance for Great Britain, that Responsible Person must have a UK established address — a mail-forwarding service or PO box does not count — and must keep a Product Information File that includes the product safety report, a description of the product, how good manufacturing practice has been followed, and "evidence for the cosmetic product's effects", retained for ten years after the last batch. Separately, the product's safety "must be checked by a qualified safety assessor" before you make it available, and the product must be notified through the Submit Cosmetic Product Notifications service, which the Office for Product Safety and Standards runs.

So the file already exists as an obligation. The claim evidence is a part of it you may not have filled in.

One boundary to keep in mind: this is the Great Britain regime. Northern Ireland follows the applicable EU regime, and the texts are close but not identical — if you sell into NI, check that separately rather than assuming.

The advertising code

The CAP Code is written by the Committee of Advertising Practice and administered by the Advertising Standards Authority. It is self-regulation, not statute, and it applies to your website, your shop listing and your Instagram post as much as to a magazine page.

From Section 3, Misleading advertising:

• 3.1 — "Marketing communications must not materially mislead or be likely to do so."
• 3.2 — obvious exaggerations ("puffery") and claims the average consumer is unlikely to take literally are allowed, provided they do not materially mislead.
• 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."
• 3.13 — claims must not be presented as universally accepted if a significant division of informed or scientific opinion exists.

From Section 12, which covers beauty products:

• 12.1 — objective claims must be backed by evidence, if relevant consisting of trials conducted on people.
• 12.7 — references to the relief of symptoms or the superficial signs of ageing are acceptable if they can be substantiated; unqualified claims such as "cure" and "rejuvenation" are not generally acceptable, especially for cosmetic products.
• 12.22 — the one people forget: claims about the action a cosmetic has on or in the skin should distinguish between the composition of the product and any effects brought about by the way it is applied, such as massage.

Rule 3.7 is the one that decides your printing schedule. The evidence has to be in your hands before the copy goes out, not assembled if someone complains.

What to do with it: before the labels go to print, put every sentence on the pack through the self-check below.

The self-check, in five questions

1. Write the claim down, word for word, as it will appear.
2. Is it about the ingredient or the product? If a reader will hear an ingredient statement as a promise about the product, Annex paragraph 3(6) is now your problem, not a technicality.
3. What document do you actually hold? Name the study, its method, its subjects and its concentration. "A chart I saw" is not a document.
4. Is that document about the thing you are selling, at the level you are selling it at? A raw material at 10% on a rabbit's ear is not your 4% face oil.
5. If not — commission a test or change the sentence. Those are the only two options; there is no third.

All five claims above are one thing said five ways: an ingredient statement wearing a product statement's clothes. The evidence supports narrower sentences — jojoba is rich in wax esters; the oils Choe and colleagues tested stayed within the superficial 0–20% of the stratum corneum; a rabbit-ear grade is a screening signal for a raw material. It supports almost nothing about the jar.

That boundary is the same discipline as reading a certificate of analysis: know what was measured, on what, at what concentration — and refuse to say more.

Sources

• Fulton J. E. Comedogenicity and irritancy of commonly used ingredients in skin care products. Journal of the Society of Cosmetic Chemists 40(6), 321–333, November/December 1989. library.scconline.org
• Mills O. H. Jr, Kligman A. M. A human model for assessing comedogenic substances. Archives of Dermatology 118(11), 903–905, 1982. PubMed 7138047
• Draelos Z. D., DiNardo J. C. A re-evaluation of the comedogenicity concept. Journal of the American Academy of Dermatology 54(3), 507–512, 2006. PubMed 16488305
• Picardo M., Ottaviani M., Camera E., Mastrofrancesco A. Sebaceous gland lipids. Dermato-endocrinology 1(2), 68–71, 2009. PubMed 20224686
• Smith K. R., Thiboutot D. M. Sebaceous gland lipids: friend or foe? Journal of Lipid Research 49(2), 271–281, 2008. PubMed 17975220
• Gad H. A. et al. Jojoba oil: an updated comprehensive review on chemistry, pharmaceutical uses, and toxicity. Polymers 13(11), 1711, 2021. PubMed 34073772
• Choe C., Schleusener J., Lademann J., Darvin M. E. In vivo confocal Raman microscopic determination of depth profiles of the stratum corneum lipid organization influenced by application of various oils. Journal of Dermatological Science 87(2), 183–191, 2017. PubMed 28522139
• Stamatas G. N. et al. Lipid uptake and skin occlusion following topical application of oils on adult and infant skin. Journal of Dermatological Science 50(2), 135–142, 2008. PubMed 18164596
• Regulation (EC) No 1223/2009, Article 20 (Product claims), as retained GB law. legislation.gov.uk — consulted 22 September 2026.
• Commission Regulation (EU) No 655/2013, Annex, Common Criteria, paragraphs 1 to 6, as retained GB law. legislation.gov.uk — consulted 22 September 2026.
• Committee of Advertising Practice. CAP Code, Section 3 "Misleading advertising" (rules 3.1, 3.2, 3.7, 3.13) and Section 12 "Medicines, medical devices, health-related products and beauty products" (rules 12.1, 12.7, 12.22) — consulted 22 September 2026.
• Office for Product Safety and Standards. Making cosmetic products available to consumers in Great Britain. gov.uk — consulted 22 September 2026.
• CTPA. Claims, advertising and communication. ctpa.org.uk — consulted 22 September 2026.