Ascorbyl Palmitate

Ascorbyl palmitate is the oil-soluble ester of vitamin C, and Fulton's 1989 rabbit-ear assay scored it 2 of 5 — borderline by his own key, a single three-rabbit experiment with no independent replication identified. It is the one real number in the vitamin C aisle, and it belongs to this molecule, not to ascorbic acid: there is no comedogenicity assay of ascorbic acid we can find, and Fulton prints no ascorbic acid row. We rate it Caution at Low confidence.

What it is

Ascorbyl palmitate is a fat-soluble ester of vitamin C: L-ascorbic acid with a palmitic-acid tail attached so that the molecule will dissolve in the oil phase of a formula. Formulators reach for it as an antioxidant and as a more stable, oil-compatible way to carry vitamin C activity — plain ascorbic acid is water-soluble and oxidises quickly in water and air, and the ester is one of the workarounds. The Cosmetic Ingredient Review's 1999 assessment reported it in use at 0.01 to 0.2% in leave-on formulations, and described its vitamin C activity as approximately equal to that of L-ascorbic acid — a statement about the vitamin activity of the molecule, not a claim that the ester delivers as much vitamin C into skin or performs equivalently in use. On a label it is Ascorbyl Palmitate. It is a different molecule from ascorbic acid, and from the water-soluble derivatives (sodium ascorbyl phosphate, magnesium ascorbyl phosphate, ascorbyl glucoside) that share the vitamin C name, which is the distinction this page turns on.

Why we rate it Caution

We rate it Caution, at Low confidence, on a single legacy rabbit-ear assay. Fulton's 1989 survey — the source of nearly every comedogenic number in circulation — prints "Ascorbyl palmitate" at 2 in Table I. Read off the 400dpi transcription of that table held in this repository, the row carries no asterisk, so it is not qualified by any source-of-material footnote; it is a flat 2. The method behind the number is the one behind every score in that table: the ingredient diluted to roughly 10% in propylene glycol, applied to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, the follicles then scored for keratosis on a 0 to 5 scale. By Fulton's own published key, 0 to 1 "is not considered significant," 2 to 3 is "borderline," and 4 to 5 is "considered positive." A 2 is the bottom of borderline: not a clean result, and not a positive one. What is unusual about this entry, on a site whose recurring finding is that a circulating score belongs to some other molecule, is that here it does not. There is no dropped word and no neighbouring row: the material Fulton tested is the material on the label. That is worth stating plainly, because the adjacent case is the opposite. Ascorbic acid — vitamin C itself — has no row in Fulton's table at all, and the flat 0 the charts hand it is unmeasured; the nearest real number is this one, the ester's 2, and it gets read across to the acid constantly. Here the 2 is at home. What the 2 rests on is thin: one three-rabbit experiment, from one investigator, in one rabbit-ear assay, with no independent replication identified and no human data we could trace. That is the whole basis for the rating, and the reason the confidence is Low.

What the evidence doesn’t tell you

This is one rabbit-ear reading and nothing else. We identified no comedogenicity assay of ascorbyl palmitate other than Fulton's 1989: it has no row in Fulton, Pay and Fulton's separate 1984 rabbit-ear paper, whose own key reads 1–2 as not significant and 3 or above as positive; it is not among the thirty-two materials Morris and Kwan tested in 1983, nor among the fourteen in Nguyen, Dang and Maibach's 2007 assay, and we found no human comedone count for it in the searches we ran. The lists that print a 2 — Banish among them — are republishing Fulton's figure, not corroborating it, so the number's apparent ubiquity is one assay quoted many times, not many assays agreeing. Two things circulate that are worth correcting: that the 2 "is not based on any study" (it is — Fulton's, weak but real), and that ascorbyl palmitate has "shown comedogenic potential in studies" (we found one, not several). The gap between the test and the product is wide and unmeasured. Fulton read the 2 at roughly 10% in propylene glycol on a rabbit ear; the Cosmetic Ingredient Review's 1999 assessment reported the ingredient in use at 0.01 to 0.2% in leave-on cosmetics, historical survey data rather than a current figure — one to three orders of magnitude lower, in different bases, on human skin. The assay does not tell us what ascorbyl palmitate does at the concentrations it is actually used at, and we are not going to infer from the concentration gap that it is therefore safe, because that inference has no measurement behind it either. The CIR's 1999 assessment concluded these ascorbic-acid esters are safe as used in cosmetics, but that is a safety conclusion, drawn from irritation, sensitisation and toxicity data; it counted no comedones, and safety is a different question from comedogenicity.

Where you’ll see it

Antioxidant and vitamin C products, most often the oil-based or anhydrous ones, where an oil-soluble form of vitamin C is easier to stabilise than the water-soluble acid: serums, moisturisers, balms and some cleansers, labelled Ascorbyl Palmitate. The Cosmetic Ingredient Review's 1999 assessment reported it in over a thousand formulations at 0.01 to 0.2%, use data from that period rather than a current market count. It is also used, at similar low levels, purely as an antioxidant to protect other oils in a formula from going rancid rather than as an active in its own right. We are not going to read a concentration off label position, which ordering rules below 1% make unreliable.

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 nearly every comedogenic score in circulation, read here off the 400dpi transcription of Table I held in this repository rather than through a list quoting it. Method: the ingredient diluted to roughly 10% in propylene glycol, applied to the inner ear of three New Zealand albino rabbits, five days a week for two weeks, follicles scored for keratosis on a 0 to 5 scale where, by Fulton's own key, 2 is "borderline." Table I prints "Ascorbyl palmitate — 2," with no asterisk on the row, so no source-of-material footnote qualifies it. This is the only comedogenicity measurement of the exact molecule that we hold, and it is a single three-rabbit experiment from a single investigator.
2. Fulton JE Jr, Pay SR, Fulton JE 3rd. "Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear." J Am Acad Dermatol 10(1):96–105 (1984) An earlier, separate rabbit-ear study from the same lead author, on its own 0 to 5 scale whose key is not the 1989 key: 1 to 2 is read as not significant and 3 or above as positive, so its numbers cannot be carried across to 1989 numbers without each paper's own key. Cited for a verified absence: it prints no ascorbyl palmitate row, so it offers no second reading of the material.
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 other major rabbit-ear survey, six years before Fulton 1989 and on the same 0 to 5 scale: undiluted material unless stated, three rabbits, fourteen applications, microscopic grading. Its thirty-two materials are seven lanolins, nine vegetable oils, eleven esters and five surfactants. Cited for an absence: ascorbyl palmitate is not among them, so it offers no second reading to confirm or contradict Fulton's 2.
4. Andersen FA (ed.), Cosmetic Ingredient Review. "Final Report on the Safety Assessment of Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate." Int J Toxicol 18(Suppl 3):1–20 (1999) An expert-panel SAFETY review, abstract read verbatim. It reports ascorbyl palmitate as an ester of ascorbic acid with a long-chain fatty acid, functioning as an antioxidant, used in the survey behind that 1999 report at 0.01 to 0.2% in over a thousand formulations — use data of that period, not a current count — with vitamin C activity described as approximately equal to L-ascorbic acid, which speaks to the vitamin activity of the molecule rather than to how much vitamin C it delivers into skin or how it performs in use. It concludes the ingredients are "safe for use as cosmetic ingredients in the present practices of use." Cited for what it is, its use concentration, and the distinction it forces: the assessment contains no comedogenicity data and counted no comedones, so a safety clearance is not evidence of non-comedogenicity.
5. Banish — "The Ultimate Guide to Acne-Causing Ingredients" A consumer "pore-clogging" ingredient guide run by a skincare brand, cited as an example of where a reader will actually meet the 2, not as evidence. Its own article states that its tables descend from the Fulton rabbit-ear lineage, so its 2 for ascorbyl palmitate is that same 1989 figure re-printed, not an independent measurement.

Others in the same family

Antioxidants behave similarly enough that the evidence for one is often wrongly read across to the others. These are its structural relatives, not a guess.

• Ascorbic Acid Clear Low
• Tocopherol Caution Low

Last reviewed 2026-08-12 · How we decide

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