Myristyl Lactate

Myristyl lactate is rated Clogging, and unlike a good many of the numbers on the pore-clogging lists, the 4 that follows it is real: James Fulton scored it in a rabbit's ear in 1989, and gave it a 5 in the same model five years earlier, that time at a stated dilution. But both readings are his own; no other laboratory's assay of it appears in the corpus we searched, and we found no human measurement of it there — so the number is a genuine rabbit-ear positive, and nothing more than that.

What it is

A liquid-to-soft emollient ester: the ester of myristyl alcohol (tetradecanol, a fourteen-carbon fatty alcohol) and lactic acid. On a label it is Myristyl Lactate; its CAS number is 1323-03-1, its molecular formula C17H34O3, and its molecular weight about 286. Formulators use it as an emollient — it gives slip and a smooth after-feel — in moisturisers, dry-skin preparations and colour cosmetics. Two neighbours are worth keeping distinct from it, because the "myristyl/myristate" cluster is easy to blur. Myristyl myristate is a different molecule — the ester of myristyl alcohol and myristic acid — with its own entry and its own rating. Isopropyl myristate, the substance Fulton used to define the top of his scale, is different again. Myristyl lactate is the only one of the three built on lactic acid, and its acid group is esterified rather than free, so it is not a free alpha-hydroxy acid; the Cosmetic Ingredient Review assessed it alongside cetyl lactate, among the esters of lactic acid rather than among the acids themselves.

Why we rate it Clogging

We rate it Clogging, at Low confidence, and the honest description of the evidence is two rabbit-ear readings from one author, with nothing else behind them. The number you will see first. On the pore-clogging lists myristyl lactate scores 4 out of 5. Unlike several of the numbers this site exists to correct, that 4 is not invented and it is not borrowed from a differently named molecule: it traces to a printed row for this exact material. James Fulton's 1989 rabbit-ear survey in the Journal of the Society of Cosmetic Chemists — the table nearly every comedogenic score online descends from — lists "Myristyl lactate" at 4, with no asterisk against the cell. The row sits among the esters, between isostearyl isostearate and myristyl myristate, and outside Section VI, Oils, the section whose heading carries his "results depend on source of raw material" caveat. We read it off a 400dpi render of the table in this project's own data file rather than from a list quoting it. By Fulton's own published key, which the lists reproducing his numbers tend to leave out, a grade of 0 to 1 "is not considered significant," 2 to 3 is "borderline," and 4 to 5 is "uniformally reproduceable and considered positive." So a 4, on his terms, is a firm positive rather than a borderline one. What produced that number. The 1989 assay applies the ingredient at roughly 10% in propylene glycol to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, and the follicles are then scored for keratosis under a micrometer. It is a screen for follicular plugging in a rabbit's ear, not a measurement on a human face, and Fulton himself called his survey "not at all definitive but simply designed to stimulate research." A second reading, and it is also Fulton's. His earlier survey — Fulton, Pay and Fulton, in the Journal of the American Academy of Dermatology in 1984, now read and transcribed for this project — scored "Myristyl lactate" a 5, its top grade, under that table's "Surfactants and detergents" heading. Its method was not the same one: two New Zealand albino rabbits rather than three, one ear dosed daily for two weeks with the alternate ear as the control. The 5 carries an asterisk, and the asterisk is that paper's own preparation footnote, which reads in full: "The product or ingredient was used 'as is' if the agent was a liquid or soft solid. Others (*) were either diluted with mineral oil or incorporated into an alcohol gel at a 10% concentration." So the 1984 reading is a diluted one — but the footnote gives two routes and does not say which applied to this row, so we cannot tell you the vehicle, and in the mineral-oil case we cannot tell you the strength either. It is not the "source of raw material" asterisk that governs Fulton's 1989 oils; the two marks mean different things and are easy to swap by accident. Worth saying plainly rather than smoothing over: the higher of the two readings is the diluted one. Neither paper gives us a way to explain that, and we are not going to invent one. The 1984 scale also read differently from the 1989 one. There, "a minimal grade of 1 to 2 is not considered significant," while "a grading score of 3 or above is uniformly reproducible and considered positive" — so on that paper's terms a 5 is strongly positive, and a 3 that would be merely borderline in 1989 counts as positive in 1984. Two surveys, five years apart, both scoring it in the range each paper calls positive: as far as it goes, the number holds up. How far it goes is the point. Both readings are the same author's, in the same animal model. That is corroboration, but it is not independent corroboration, and the distinction matters here more than usual. The obvious place to look for a second opinion is Morris and Kwan's 1983 rabbit-ear assay, the one legacy paper that openly disagrees with Fulton in print and that tested a long list of the same esters — decyl oleate, isopropyl palmitate, isopropyl isostearate, octyl palmitate, myristyl myristate among them. It did not test myristyl lactate. So where its near neighbour myristyl myristate has a contradicting second lab on record (Morris and Kwan scored "Myristyl Myristate (50% in Mineral Oil)" 0 to 1, against Fulton's 5), myristyl lactate has no second lab at all. The rating rests on one investigator's two readings, and that is the whole of the measured evidence.

What the evidence doesn’t tell you

Everything numeric here comes from rabbits' ears, and from a single laboratory. In the corpus we searched — the legacy assays behind this site — we found no independent, non-Fulton comedogenicity assay of myristyl lactate: it is absent from Morris and Kwan's 1983 table, and no other primary document we located scores it. Neither could we find a human comedogenicity study of it in that literature — no cyanoacrylate follicular biopsy, no facial trial, no comedone count on a person that we have been able to find. Two readings by the same author agreeing with each other is a weaker thing than two laboratories agreeing, and it is worth saying plainly rather than presenting the pair as if it were a consensus. The two Fulton readings are not a replication of each other, either. 1989 scored it 4, using three rabbits and the ingredient at roughly 10% in propylene glycol. 1984 scored it 5, using two rabbits, and — because that row is starred — a diluted preparation rather than the neat application its unstarred rows received, judged against a threshold set one grade lower. Different animal count, different preparation, different verdict key. Both results fall in their own paper's positive band, so the direction is stable, but the one-grade gap between them is a reminder that the assay is a coarse, noisy instrument even in the hands that built it. Neither paper records what material it actually had. No supplier, no purity, no lot, no free myristyl alcohol or residual lactic acid, and nothing that would let us check whether the 1984 and 1989 samples were the same commercial grade as each other, let alone as anything sold today. Two papers tested something called myristyl lactate; that the name matches is all we can verify. The rabbit-ear model itself has been contested for decades. Frank asked in 1982 whether it was "prophetic of acnegenicity" at all; Draelos and DiNardo in 2006 found finished products testing non-comedogenic despite containing ingredients the rabbit assay had scored comedogenic; and a 2025 review in JAAD Reviews found that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label. None of that overturns myristyl lactate's number — it widens the error bars around it. Nor does either grade transfer intact to a finished formula: the assay's vehicle, its daily dosing and its isolated-material condition are not a product, even where a nominal percentage happens to overlap one. Finally, the safety record is not a comedogenicity record, and the two are easy to blur. The Cosmetic Ingredient Review has assessed myristyl lactate and concluded it safe as used, reporting an acute oral LD50 in rats above 20 g/kg and minimal skin irritation (with one study finding the undiluted ester moderately irritating). That is a statement about toxicity and irritation. It is not a comedone count, and being safe and low-irritation is a different finding from being non-comedogenic.

Where you’ll see it

On a label it reads Myristyl Lactate. It is used as an emollient — for slip and a smooth, non-greasy after-feel — in moisturisers and other leave-on skincare, in dry-skin preparations, and in colour cosmetics. The Cosmetic Ingredient Review's assessment records cosmetic use of it, and concluded it safe in the practices of use it reviewed. These are illustrative product categories, not a measured prevalence: we have not audited the market, and we are not going to tell you where it tends to sit on an ingredient list, because label position is not a concentration. Keep it separate from the other "myristyl/myristate" esters near it — myristyl myristate and isopropyl myristate above all — which are different molecules with their own entries.

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 of the 4, and of nearly every comedogenic number in circulation. A rabbit-ear survey: ingredient at roughly 10% in propylene glycol, inner ear of New Zealand albino rabbits, three rabbits per assay, five days a week for two weeks, follicles scored for keratosis under a micrometer. Table I lists "Myristyl lactate" at 4 on a 0–5 scale, with no asterisk on the cell, among the ester rows and outside the asterisked Section VI, Oils — an ordinary reading, not the reference standard (that is isopropyl myristate). Read here from the primary table, transcribed from the journal scan at 400dpi in this project's own data file, not from a list quoting it. Fulton's own key: 0–1 "not considered significant," 2–3 "borderline," 4–5 "considered positive." He described the survey as "not at all definitive."
2. Fulton JE Jr, Pay SR, Fulton JE III. "Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear." J Am Acad Dermatol 10(1):96–105 (1984) Fulton's earlier rabbit-ear survey, by the same lead author five years before the famous 1989 table, read and transcribed for this project from a 400dpi render of the journal scan. Method: two New Zealand albino rabbits per test, one ear dosed daily for two weeks, the alternate ear the control, borderline cases confirmed by microscopic biopsy. Its Table I scores "Myristyl lactate" a 5 — its top grade, on a 0–5 scale — under the "Surfactants and detergents" heading, with an asterisk. The asterisk is the paper's own preparation footnote: agents that were liquids or soft solids were used "as is," while starred ones "were either diluted with mineral oil or incorporated into an alcohol gel at a 10% concentration." The footnote does not say which of the two applied to this row. It is NOT the 1989 "source of raw material" asterisk. Its grade key also differs from 1989's: here 1–2 is "not significant" and 3 or above is "uniformly reproducible and considered positive," so a 5 is strongly positive on its own terms. Cited as a second reading that agrees in direction with the 1989 positive — same author, same model, different preparation and different key, and not an independent confirmation.
3. Morris WE, Kwan SC. "Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients." J Soc Cosmet Chem 34:215–225 (1983) The one independent legacy laboratory that ran the same 0–5 scale, six years before Fulton's famous table, and the paper that says in print that its results "conflict with the high scores published by Fulton et al." Thirty-two rows: seven lanolins, nine vegetable oils, eleven esters, five surfactants. Cited here for what it does NOT contain: there is no myristyl lactate row in it, so there is no second-laboratory reading of this material to check Fulton's against. Its relevance is the near neighbour — it scores "Myristyl Myristate (50% in Mineral Oil)" 0 to 1 against Fulton's 5 — which shows what a contradicting second lab looks like, and that myristyl lactate does not have one. An absent row is not a low score.
4. Cosmetic Ingredient Review. "Final Report on the Safety Assessment of Cetyl Lactate and Myristyl Lactate." Journal of the American College of Toxicology, vol. 1 (1982) An expert-panel safety assessment, cited for what it is and not for what it is not. Read via the CIR/journal abstract and secondary summaries, not the full report, so no page numbers are asserted here. It reports myristyl lactate as an ester of myristyl alcohol and lactic acid with an acute oral rat LD50 above 20 g/kg, minimal skin irritation in Draize testing (one study finding the undiluted ester moderately irritating) and no eye irritation, and concludes the ester safe in the practices of use reviewed. It is a toxicity and irritation review, NOT a comedogenicity study, and says nothing about follicular plugging. Safe and low-irritation is a different claim from non-comedogenic.
5. Frank SB. "Is the rabbit ear model, in its present state, prophetic of acnegenicity?" J Am Acad Dermatol 6(3):373–377 (1982) The earliest peer-reviewed challenge to the assay both of this page's numbers come from. Cited for a caveat that applies symmetrically: the model's weaknesses undermine an alarming 4 exactly as much as they would a reassuring 0. It is not a test of myristyl lactate.
6. Draelos ZD, DiNardo JC. "A re-evaluation of the comedogenicity concept." J Am Acad Dermatol 54(3):507–512 (2006) A "Current Issues and Opinion" piece that tested finished products on human upper backs and found products testing non-comedogenic despite containing ingredients the rabbit assay had scored comedogenic. It is not a same-substance rabbit-versus-human validation and we do not present it as one; it is evidence that an isolated ingredient's grade does not transfer intact to the formula it ends up in. It did not test myristyl lactate.
7. "Comedogenicity in cosmeceuticals: a review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed review of the whole field. 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. Finds that no standardised comedogenicity test exists and that the label "non-comedogenic" is unregulated. Cited for the field-wide caveat that sits under every legacy number on this site, and with particular force under one that has been measured only in a rabbit's ear.
8. Face Reality Skincare — pore-clogging ingredient list The only source our own rating file names for this ingredient, cited so a reader can see what that basis is. It is an acne clinic's alphabetical avoid-list: "Myristyl Lactate" appears on it, with no number, no method, no comedone count, no denominator and no citation. It is an assertion that the ingredient is best avoided, made by people who see acne patients — informed, but not a measurement, and we do not dress it up as one. We did not trace where the 4 that circulates for this material was copied from or by whom, and we did not confirm that acne.org's compiled list carries a myristyl lactate row at all; acne.org now describes its ratings as a synthesis of eleven rabbit-ear or human studies rather than a straight republication of Fulton, so matching numbers on consumer charts are not independent measurements and we are not going to claim more about the chain than we checked.

Others in the same family

Esters 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 esters as a family ›

• Butyl Stearate Clogging Low
• Caprylic/Capric Triglyceride Clear Low
• Cetyl Acetate Clogging Low
• Cetyl Palmitate Clear Low
• Decyl Oleate Clogging Low
• Isocetyl Stearate Caution Low
• Isopropyl Isostearate Clogging Low
• Isopropyl Linoleate Clogging Low

Last reviewed 2026-08-01 · How we decide

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