Is sulfur comedogenic?
Short answer
Conflicting evidence: Conflicting or context-dependent evidenceThe 1984 rabbit ear assay raised a comedogenicity concern for precipitated sulfur and then questioned it in the same breath, noting that sulfur's clinical effectiveness as an acne treatment remained strong. The source both raises and doubts the concern, so the honest reading is unresolved rather than settled either way. Sulfur is used to treat acne, and nothing here is a reason to change a treatment.
Recorded as Sulfur · dataset record sulfur · reviewed 2026-08-06
What the evidence actually is
The material was applied to animal skin — in this dataset, a rabbit ear assay. It is a screening model, and the human-assay literature reports that it overreacts to comedogenic materials relative to human testing.
What the sources report
The cited rabbit ear assay explicitly questions whether precipitated sulfur is truly comedogenic, noting that its clinical effectiveness as an acne treatment remained strong. The same source therefore both raises and doubts the concern.
What this does not cover
This is an ingredient used to treat acne, and the cited source treats the animal-model signal as being in tension with clinical experience. Nothing here establishes how a finished product containing sulfur will behave on your skin.
Why people ask about Sulfur
Sulfur turns up in spot treatments and masks bought specifically for breakouts, so finding it on a comedogenic list produces the same jolt as benzoyl peroxide does. It also has a distinctive smell that makes people conscious of it as an ingredient, and it is common in older, cheaper acne products that get recommended long after the evidence behind them stopped being examined.
Where the circulating rating for Sulfur comes from
This is the clearest case in the dataset of a rating outrunning its source. Fulton's 1984 paper is where the comedogenicity flag for precipitated sulfur originates, and that same paper explicitly questions whether the ingredient is truly comedogenic given how well it performed clinically. Lists that carry the number forward reproduce the flag and drop the doubt attached to it. The 2016 human-assay methodology work adds the other half of the problem: the rabbit ear model has been reported to overreact to comedogenic materials relative to human testing.
Names Sulfur appears under
Declared as Sulfur, or Sulphur in British spelling, and often as precipitated sulfur — which is the form the 1984 assay tested. Colloidal sulfur and sulfur in combination products such as sodium sulfacetamide preparations are different declared materials, and the finding here is not carried across to them.
Recognised in this dataset as Sulfur, and through the recorded aliases sulphur, precipitated sulfur, precipitated sulphur. Matching is exact: there is no fuzzy matching anywhere in this tool, so a name not listed here is reported as unrecognised rather than guessed at.
Questions about sulfur
Why is an acne treatment on a comedogenic list at all?
Because the 1984 assay tested therapeutic products and cosmetic ingredients side by side in the same animal model, so acne treatments were screened by the same method as everything else. The paper itself noticed the tension in the sulfur result and said so. What survived into circulating lists was the flag, not the paper's own hesitation about it.
Does this mean sulfur will break me out?
Nothing reviewed here establishes that. A screening signal in animal skin that the reporting authors themselves questioned is not a prediction about your face, and the human-assay work in this dataset reports that this model overreacts. It is also not a finding of safety — the question is open on these sources.
Is sulfur in a mask different from sulfur in a spot treatment?
The sources do not answer that, but they do establish why the question matters: the 2006 human-assay work found that finished products built with ingredients flagged as comedogenic are not necessarily comedogenic. Concentration, vehicle and contact time all differ between those formats, and none of them are captured by an ingredient-level flag.
Sources cited on this page
These are the sources attached to this record. Nothing on this page is drawn from anything else.
Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear
Fulton JE Jr, Pay SR, Fulton JE 3rd. Journal of the American Academy of Dermatology, 1984. Peer-reviewed. doi:10.1016/s0190-9622(84)80050-x
Rabbit ear assay. This is the historical origin of most ingredient-level comedogenicity lists in circulation today. The assay is a screening model in animal skin, not a measurement of how a finished cosmetic behaves on a human face. Later work (see src-baek-2016) reports that this model overreacts relative to human testing.
Analysis of comedone, sebum and porphyrin on the face and body for comedogenicity assay
Baek JH, Ahn SM, Choi KM, Jung MK, Shin MK, Koh JS. Skin Research and Technology, 2016. Peer-reviewed. doi:10.1111/srt.12244
Human comedogenicity assay methodology study in 66 volunteers. States that the rabbit ear model can replace human testing for screening purposes but that a number of studies have pointed out its disadvantage of overreacting to comedogenic materials. This is the citation behind every 'animal-model evidence may overstate the result' limitation in this dataset.
Record reviewed 2026-08-06 by pore-checker prototype dataset compilation (not clinically reviewed).