Lauric Acid

Lauric acid sits at the peak of the comedogenic curve in two independent rabbit studies and is also the fatty acid shown in a dish to kill the bacterium implicated in acne — two findings that, as far as we can find, have never been tested against each other on a human face.

What it is

A saturated medium-chain fatty acid, twelve carbons long (C12). The Cosmetic Ingredient Review describes it as produced by the hydrolysis, usually saponification, of animal or vegetable fats and oils, followed by fractional distillation, and notes it is commonly isolated from coconut oil — of which it makes up roughly half. Its reported cosmetic function is not what most people assume. CIR lists lauric acid as a cleansing surfactant and a fragrance ingredient, not an emollient. In practice it is a soap precursor. Where it appears near the top of a foaming cleanser's ingredient list beside potassium hydroxide or sodium hydroxide, the two react and it becomes potassium laurate or sodium laurate — soaps that CIR lists as separate cleansing surfactants in their own right. That matters for reading a label. The lauric acid named on a cleanser is largely not the substance left in the finished product, and what remains is rinsed off.

Why we rate it Caution

We rate it Caution at Low confidence, and the two halves of that sentence are doing different jobs. The Caution is well earned. Unusually for this database, it does not rest on a single study: two animal experiments, run eighteen years apart by different groups, agree. The earlier is Kanaar 1971, in Dermatologica — four albino rabbits, a 5% alcohol solution of each fatty acid, 3 ml applied once daily, five days a week, for six weeks, to the external ear canal. The abstract records the result for the other saturated acids in one sentence: myristinic, palmitinic and stearinic acid induced no distinct alterations. Lauric acid and oleic acid produced erythema within a day, then desquamation, then distinct follicular keratosis within a month — still visible six weeks after the applications stopped. The later is Fulton 1989, in the Journal of the Society of Cosmetic Chemists — the paper the 0-5 scale everyone quotes comes from. Fulton diluted each ingredient to about 10% in propylene glycol, applied it to the inner ear of New Zealand albino rabbits, three rabbits per assay, and scored the follicles for keratosis. Lauric acid scored 4 out of 5, the highest of any straight-chain fatty acid he tested. His run reads caprylic 1, capric 2, lauric 4, myristic 3, palmitic 2, stearic 2-3, eicosanoic 2, behenic 0. The first stated conclusion of the paper is that medium-chain-length fatty acids are more potent than short- or long-chain fatty acids at producing follicular keratosis. Lauric acid is the peak of that curve; Fulton names it in his discussion as one of the mid-chain fatty acids that cause follicular hyperkeratosis. Different labs, different decades, different vehicles, different sites on the animal, different concentrations, different durations, same result. That is a stronger base than almost anything else on a comedogenic list. The Low confidence is the other half. Both experiments are rabbit ears. Our confidence tier reflects what kind of evidence we hold, not how much we like it, and what we hold here is two legacy animal assays — not a human study, and not dermatological consensus about lauric acid itself. Two agreeing legacy assays is a better position than one, and the tier has no way to say so. It is still, in both cases, a rabbit.

What the evidence doesn’t tell you

No study we can find has established that any of this happens on a human face, and Fulton is candid in the paper about what that means. He writes that the disadvantage of the model is its extreme sensitivity, and, plainly, that while materials found non-comedogenic in the rabbit appear non-comedogenic in the human model, "whether highly comedogenic ingredients in the rabbit ear assay are always comedogenic in humans still remains uncertain." The man who produced the 4 did not claim it transferred. Draelos and DiNardo argued in 2006 that rabbit-ear results do not reliably predict comedogenicity in human skin, and a 2025 review in JAAD Reviews found that no standardised comedogenicity test exists at all. The number is also not a fixed property of the molecule. Fulton retested the same fatty acids in a second solvent and reported the results in his own Table III — lauric acid graded 3 in ethyl ether or acetone and 4 in sunflower oil, and myristic acid moved from 1 to 3. What moved the score was the vehicle. Note what did not move it. The common reassurance that low concentrations are safe has no support in the primary source: Fulton addressed that claim directly and rejected it. "We are not convinced of the statement that lower concentrations of these compounds can be safely used with no comedogenic consequences." He was not convinced, nobody has settled it since as far as we can tell, and we are not going to repeat a dose-dependence our own source denies. Lauric acid has been applied to human faces exactly once in a way we can find. Kozan, Guner and Akyol, in Dermatologic Therapy in 2020, gave 90 people with acne vulgaris one of three twice-daily topicals for eight weeks, 30 per arm, and graded facial acne. One arm used a leave-on combining 4% niacinamide, 1% gallic acid and 1% lauric acid. All three arms improved. It answers nothing. Lauric acid was one percent of a three-ingredient combination that included niacinamide, so nothing in the result can be attributed to it; there was no vehicle arm to compare against; and the paper's own title calls it retrospective while its methods describe patients randomly divided into groups. It is the only human facial data that exists, and it cannot carry the question. The other half of the literature is unfinished in the same way. Nakatsuji and colleagues reported in the Journal of Investigative Dermatology in 2009 that lauric acid's minimum inhibitory concentration against Propionibacterium acnes — now Cutibacterium acnes — was more than fifteen times lower than benzoyl peroxide's, and that it was not cytotoxic to human sebocytes. Both of those were in culture. They then injected and applied it to mouse ears colonised with the bacterium and saw fewer bacteria, less swelling and less granulomatous inflammation. Yang and colleagues, in Biomaterials the same year, showed the same killing by liposomal lauric acid in vitro; Pornpattananangkul and colleagues carried it back into the mouse ear in 2013. A mouse ear deliberately infected with C. acnes is not acne. Mice do not get acne, and none of these papers counted a comedone. What does not exist — and this page previously said it more sweepingly than the evidence allows, four paragraphs after describing the study that contradicts it — is a trial that ISOLATES topical lauric acid. Kozan's ninety patients did receive it on their faces, inside a three-active product. No study we can find has applied lauric acid alone, at a known concentration, to human skin and counted what happened to the follicles. "Nobody has isolated it" and "nobody has tried it" are different sentences, and we had both on the page. The finding is real, and it is a laboratory result, not a treatment. Nothing here says lauric acid treats acne, and you should be suspicious of anything sold on the claim that it does. What is missing is the obvious study: the two halves of this literature have never met. The comedogenicity work never looked for an antibacterial effect and the antibacterial work never looked for comedones. An ingredient that may plug a follicle and kill the bacterium inside it is not a contradiction anyone has resolved. It is a question nobody appears to have asked properly.

Where you’ll see it

Cleansers, first and mostly. It appears as Lauric Acid, usually high on the list of a foaming face or body wash, next to potassium hydroxide or sodium hydroxide — the pairing that turns it into soap. The coconut oil relationship is the one most worth getting right, because we got it wrong. Coconut oil is roughly half laurate by fatty-acid profile, and it is tempting — everyone does it — to treat that as "coconut oil is half lauric acid." It is not. In coconut oil the laurate is bound into TRIGLYCERIDES, esterified to glycerol; free lauric acid is a different chemical species, and it takes hydrolysis to get from one to the other. This page used to call them "the same molecule." They are not the same molecule, and saying so was precisely the material-identity error we exist to catch in other people's lists. It also referred to Fulton's score for coconut oil. There is no such score. Fulton's table has no coconut oil row — he tested coconut BUTTER — and we retracted that number on our own coconut oil page on 12 July, then left it standing here for a day, on a page nobody thought to re-read. That is how these numbers survive for thirty years: not because anyone defends them, but because a correction in one place is not a correction. Our build now refuses to compile if a retracted claim reappears anywhere on the site, which is the only reason you are reading this sentence instead of the old one. Free lauric acid, when declared, is overwhelmingly a rinse-off soap precursor, neutralised in the pot and washed off the face. As a declared leave-on it is much less common; the only human study we found used it at 1%.

Sources

Each source says what it actually is. Several widely-cited “sources” for comedogenic ratings are republishing the same 1989 assay, and counting them as independent agreement is how a thin evidence base gets made to look thick.

1. Fulton JE. "Comedogenicity and irritancy of commonly used ingredients in skin care products." J Soc Cosmet Chem 40:321-333 (1989) The primary source for the 0-5 scale that nearly every list online still uses, including this one. Read in full for this page. Lauric acid scores 4 in Table I, and the paper's opening generalisation — that medium-chain fatty acids are the most potent producers of follicular keratosis — is what makes it the poster child for the whole idea. Two things in it almost nobody quotes. Table III shows the same fatty acids scoring differently in different solvents, which is why the number is not a property of the molecule. And Fulton explicitly rejects the low-concentration reassurance that is routinely attributed to him.
2. Kanaar P. "Follicular-keratogenic properties of fatty acids in the external ear canal of the rabbit." Dermatologica 142:14-22 (1971) The earliest primary experiment, and the one almost nobody citing a comedogenic rating knows exists. It predates Fulton by eighteen years and reaches the same verdict on lauric acid by a different route — which is the whole reason this rating is not a single-study rating. We were unable to obtain the full paper; the method and findings described on this page are as summarised in detail in the CIR report below, which is not the same as having read it, and we would rather say so.
3. "Final Report on the Safety Assessment of Oleic Acid, Lauric Acid, Palmitic Acid, Myristic Acid, and Stearic Acid." J Am Coll Toxicol 6(3) (1987), with CIR's 2019 re-review, "Safety Assessment of Fatty Acids and Fatty Acid Salts as Used in Cosmetics" Industry safety review, not a comedogenicity study, and useful for two separate things. It carries the detailed summary of Kanaar 1971 that we relied on, and it is the source for what lauric acid is actually doing in a formula — CIR lists its function as a cleansing surfactant and fragrance ingredient. It also records human patch-test data on formulations containing lauric acid at under 1% to 13%, which found no meaningful irritation or sensitisation. Those tests measured irritation and sensitisation. They never counted a comedone, and they are not evidence about pore-clogging in either direction.
4. Nakatsuji T, Kao MC, Fang JY, Zouboulis CC, Zhang L, Gallo RL, Huang CM. "Antimicrobial property of lauric acid against Propionibacterium acnes." J Invest Dermatol 129:2480-2488 (2009) The primary antimicrobial finding, and the most-cited paper on this ingredient. Two models, neither of them human: bacterial culture, where lauric acid's MIC was over fifteen times lower than benzoyl peroxide's, and the ear of a mouse deliberately colonised with the bacterium. Cited here as the other half of the contradiction, not as a benefit. It is a laboratory result. Nothing in it says lauric acid treats acne on a face.
5. Yang D, Pornpattananangkul D, Nakatsuji T, Chan M, Carson D, Huang CM, Zhang L. "The antimicrobial activity of liposomal lauric acids against Propionibacterium acnes." Biomaterials 30:6035-6040 (2009). PMID 19665786 Entirely in vitro. Compared lauric, palmitic and oleic acids against the bacterium in culture, found lauric the most bactericidal, and packaged it into liposomes to get around its poor water solubility. A dish, not a person.
6. Pornpattananangkul D, Fu V, Thamphiwatana S, et al. "In vivo treatment of Propionibacterium acnes infection with liposomal lauric acids." Adv Healthc Mater 2:1322-1328 (2013) The in vivo follow-up, and the closest this line of work has come to a therapy. Still a mouse ear infected with the bacterium, which is a model of infection, not of acne. Included because the distinction between "cleared an induced infection in a mouse ear" and "treats acne" is precisely the distinction the popular coverage of this ingredient collapses.
7. Kozan A, Guner RY, Akyol M. "A retrospective assessment and comparison of the effectiveness of benzoyl peroxide; the combination of topical niacinamide, gallic acid, and lauric acid; and the combination of benzoyl peroxide and erythromycin in acne vulgaris." Dermatol Ther 33(4):e13534 (2020) The only study we could find in which lauric acid was applied to human faces and the acne was counted — 90 patients, 30 per arm, eight weeks. It is also too confounded to settle anything. Lauric acid was 1% of a three-ingredient leave-on that also contained niacinamide, there was no vehicle arm, and the paper's title says retrospective while its methods say randomised. Listed because it is the whole of the human evidence, and because its weakness is the finding.
8. Draelos ZD, DiNardo JC. "A re-evaluation of the comedogenicity concept." J Am Acad Dermatol (2006) Peer-reviewed argument that rabbit-ear comedogenicity does not reliably predict what happens in human skin, and that a comedogenic ingredient does not make a finished product comedogenic. The strongest published case against taking our own headline number at face value, and part of why the confidence here is Low.
9. "Comedogenicity in cosmeceuticals: A review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) Recent peer-reviewed review of the field. Finds that no standardised comedogenicity test exists and that the rabbit-ear assay produced inconsistent results in human skin. It is a synthesis of the legacy literature, not a new measurement, and independent of Fulton only in authorship, since the corpus it surveys includes his.
10. CosDNA and Face Reality comedogenic ingredient lists Republishers of the Fulton scores, and where most readers will already have met the number 4. Neither is an independent measurement, and listing them side by side is not two sources agreeing — it is one 1989 assay quoted twice. The same is true of acne.org, Banish and Sofie Pavitt. They are named here so the reader knows where the number they have already seen came from, and they add nothing to our confidence.

Others in the same family

Fatty acids behave similarly enough that the evidence for one is often wrongly read across to the others. These are its structural relatives, not a guess. What the evidence says about fatty acids as a family ›

• Capric Acid Caution Low
• Myristic Acid Caution Low
• Palmitic Acid Caution Low
• Stearic Acid Caution Low

Last reviewed 2026-06-23 · How we decide

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