Lecithin
Lecithin is rated Clear — and unlike almost everything on a pore-clogging list, that rating rests on no measurement at all. No comedogenicity assay of it — rabbit or human — appears in the corpus we searched, and the number is not so much wrong as absent.
No assay we can find, and no comedogenic concern on record.
What it is
Lecithin is not a single molecule. It is a mixture of phospholipids — chiefly phosphatidylcholine, alongside phosphatidylethanolamine, phosphatidylinositol and others — extracted from soybean, sunflower, rapeseed or egg yolk, and — depending on grade and refining — it may still carry residual amounts of the parent oil it was separated from. The Cosmetic Ingredient Review's 2015 assessment treats it as one of seventeen related phosphoglycerides and lists its cosmetic jobs as skin- and hair-conditioning agent, emulsifier and surfactant, at reported use levels up to 50%. A formulator reaches for it because a phospholipid has a water-loving head and two oil-loving tails, which lets it sit at the boundary between oil and water and hold an emulsion together; the same geometry lets it wrap oils and actives into liposomes for delivery. On a label you will also see Hydrogenated Lecithin — the same material with its unsaturated tails saturated so it resists oxidation — which is a related but distinct ingredient: saturating the tails changes its oxidative stability, melting behaviour and how it performs, so the two are not simply interchangeable. Because "lecithin" names a natural mixture rather than a defined compound, its exact composition shifts with its source. That matters below, because it means there is no single defined substance behind the name — a particular commercial grade could of course be tested, but none in the corpus we searched was.
Why we rate it Clear
We rate it Clear, at Low confidence, and the reason for the low confidence is blunt: the corpus we searched holds no measurement of it. There is no rabbit-ear score for lecithin in it, and we identified no human comedone study of it. Fulton's 1989 rabbit-ear survey — the table nearly every comedogenic number in circulation descends from — has no lecithin row, and no phospholipid row anywhere in it. We hold all 220 of its rows transcribed by eye, and the word does not appear. Its relatives from the same plant are in the table — soybean oil at 3, maleated soybean oil at 0, the soya sterols at 0, all on Fulton's 0–5 scale — but the phospholipid fraction that lecithin is drawn from is not among them. The same holds across the other numeric assays we hold: none carries a row for it. So the Clear here is not a passing grade. It is an inference. What Clear means on this site is "no comedogenic concern on record," and for lecithin that is literally the case — there is no concern on record because there is no record. That is a different thing from an ingredient that was tested and came back low, and we would rather you knew which one you were reading. What does exist is a safety review, and it is worth being exact about what it is and is not. The Cosmetic Ingredient Review published its assessment of lecithin and sixteen related phosphoglycerides as a Final Report — its cover page reads "Final Report," released 7 April 2015 — and concluded the group is safe as used in cosmetics at the reported concentrations, up to 50%. It is a thorough document on irritation, sensitisation, systemic toxicity and the rest. It contains no comedogenicity data — no rabbit assay, no human comedone count, no follicular measurement of any kind. A safety assessment is not a comedogenicity study, and the absence of a pore finding inside one is not a pore finding. The Panel does note that phospholipids' physiologic effects "are not reproduced by application of phospholipids to the skin" — a statement about cell-membrane biology, not about follicles, and we are not going to stretch it into one. One more thing sets lecithin apart from most of what this site writes about. Usually the problem is a number that traces to nothing: a 5 from a forum post, a 4 that belongs to a different molecule. Lecithin barely carries a circulating number at all. It is absent from the large consumer avoid-lists we checked — Banish's database runs to more than 150 entries, including a dozen lanolin derivatives, and has no lecithin row; acne.org's list is drawn entirely from the dozen legacy assays, and none of those assayed lecithin. There was never a measurement to copy, which is most of why the copies leave it alone.
What the evidence doesn’t tell you
An untested ingredient is unknown in both directions, and this page is not a clean bill of health. "No assay found it comedogenic" and "an assay found it non-comedogenic" are different sentences, and only the first is true here — and it is true only because there was no assay. We cannot tell you lecithin does not clog pores. We can tell you that, across the corpus we searched, no measurement of it turns up. "Lecithin" is also not one substance. Its phospholipid make-up shifts with the source — soy, sunflower, rapeseed, egg — and, by grade, commercial lecithin may carry residual amounts of the parent oil it was separated from. Soybean oil itself sits at 3 on Fulton's 0–5 scale, in his "borderline" band, so a soy lecithin is not guaranteed to behave like a purified phosphatidylcholine, and neither shows up in the corpus we searched. Hydrogenated lecithin, the saturated version on many labels, is a third case again, and it is absent from that corpus too. A single rating across all of them is honest only because the absence is uniform: no measurement of any grade, from any source, in either direction. If one ever appears for one of them, this entry has to come apart. The reassuring-sounding claims you will meet elsewhere are not evidence either. "Lightweight, absorbs easily, won't clog pores" is a common line about lecithin; so is "may clog in very oily skin at high concentrations." Neither has a comedone count behind it. They are formulator impressions and product copy, pointing in opposite directions, and this site does not upgrade either into a finding.
Where you’ll see it
On a label it reads Lecithin or Hydrogenated Lecithin, and sometimes under a source name such as Glycine Soja (Soybean) Lecithin. The Cosmetic Ingredient Review reports the phosphoglyceride group across a wide range of leave-on and rinse-off products at up to 50%, in the roles of emulsifier, skin-conditioning agent and liposome-forming carrier. Those are the jobs it does, not a measured prevalence — we have not audited where it sits on a label or at what level, and position on an ingredient list is not a dose.
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.
- 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 number in circulation, and cited here for what it does NOT contain. Method: each ingredient diluted to roughly 10% in propylene glycol, applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, follicles scored for keratosis on a 0–5 scale. We hold all 220 rows of Table I transcribed by eye from a 400dpi render: there is no lecithin row and no phospholipid row anywhere in the paper. Related soy materials appear — soybean oil (3), maleated soybean oil (0), soya sterol (0) — but the phospholipid fraction lecithin is drawn from does not. An absent row is not a zero and not a low score; it is the absence of a measurement.
- Cosmetic Ingredient Review Expert Panel (Johnson W Jr, Bergfeld WF, Belsito DV, et al.). "Safety Assessment of Lecithin and Other Phosphoglycerides as Used in Cosmetics." Final Report, released 7 April 2015; published in Int J Toxicol (2020), doi:10.1177/1091581820953123 A safety review of lecithin and sixteen related phosphoglycerides by the Cosmetic Ingredient Review — an industry-funded panel convened by the Personal Care Products Council — not a comedogenic list and not downstream of Fulton. Document state verified from the cover page: "Final Report," released 7 April 2015 (it supersedes the 2001 CIR report's 15% leave-on limit). Cited for three things we could read in it: what lecithin is and does (skin- and hair-conditioning agent, emulsifier, surfactant; up to 50%); its conclusion that the group is safe as used; and its Panel note that phospholipids' physiologic effects "are not reproduced by application of phospholipids to the skin." It assesses safety — irritation, sensitisation, toxicity — and contains no comedogenicity data of any kind. We use it for what it says, not as evidence that lecithin does not clog pores, which it does not address.
- Banish — "The Ultimate List of Pore Clogging Ingredients To Avoid" A large consumer avoid-list that republishes the legacy rabbit-ear and human assays — its numbers track Fulton and Morris & Kwan (coconut butter 4, isopropyl myristate 5, acetylated lanolin 0). Not an independent measurement. Cited as a negative check: its database runs to more than 150 entries, including a dozen lanolin derivatives and many single-percent surfactants, and contains no lecithin, hydrogenated lecithin or phosphatidylcholine row. A negative check, not an exhaustive survey — but even these large copied lists carry no lecithin number, because there was never one to copy. Read 16 July 2026.
- acne.org — "What Is Comedogenicity, and What Ingredients Are Comedogenic?" A curated comedogenic list of 45 ingredients. Cited for its stated method, which is the point: an ingredient reaches its "Avoid" tier on at least two rabbit-ear assays or one human test, and its "Consider Avoiding" tier on a single rabbit assay. The list is built entirely from the dozen legacy studies it references (Kligman, Mills, Morris & Kwan, Fulton, Draelos), none of which assayed lecithin — so no entry there could rest on a measurement of it. A republisher of the assays, not an independent source. Read 16 July 2026.
Others in the same family
Emulsifiers 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 emulsifiers as a family ›
Last reviewed 2026-07-13 · How we decide