Spirulina
Spirulina is rated 3 to 4 on our list, a range whose top puts it in the high band, and that number is unconfirmed: we have not traced it to a published study (what unconfirmed means).
Like every rating here, it is for the raw ingredient tested alone, and a label does not print how much of it a product holds.
Is spirulina comedogenic?
Spirulina is rated 3–4 on the comedogenic scale: our list gives it a range from 3 to 4, and the band follows the 4 at the top.
A blue-green microalga rich in B vitamins, used in skincare.
- Comedogenic rating
- 3–4 out of 5 (a range on our list)
- Band
- High: Clear plugging in the rabbit-ear test. The first band to check in a leave-on product.
- Where the number comes from
- Unconfirmed. We could not trace this rating to a study we have read; the section on who rated it says what we checked.
- Composition
- Seaweed / Marine Algae / Marine Botanicals
- Also written as
- No common variants recorded
What a 3–4 means in practice
A 4 or 5 is the top of the scale. In the rabbit-ear test, Fulton 1989 counted 4 to 5 as a clear positive: the ingredient plugged the follicles, and did so repeatably. A person's skin reacts less readily than a rabbit's ear, and a product holds far less of the ingredient than the test did, so treat this band as the first thing to check in anything that stays on your skin. It does not prove the ingredient will cause a breakout. A rinse-off product is on the skin for seconds.
Two things change what this number is worth. Ingredients are listed in descending order of concentration, so spirulina near the top of a label matters far more than spirulina at the bottom. And the rating describes the raw ingredient on its own. A 2006 review in the Journal of the American Academy of Dermatology found that a rating for a single ingredient does not reliably predict how a finished formula behaves on human skin. The full story of the scale is here.
Who rated it
We could not trace the 3–4 on our list to a paper we have read. Neither paper we could read tests any algae extract. The list does not say where its numbers came from, so treat this number as unconfirmed rather than as one we can tie to a table.
Common questions
- Is spirulina comedogenic?
- Spirulina is rated 3–4 on the comedogenic scale: our list gives it a range from 3 to 4, and the band follows the 4 at the top. We have not found a published study that grades it, so treat this number as unconfirmed.
- Is spirulina non comedogenic?
- No. Spirulina is rated 3–4 on the comedogenic scale, which is the high band. That is the number on our list rather than a verdict on any product. We have not traced it to a published study, so treat it as unconfirmed.
- What is spirulina's comedogenic rating?
- 3–4 out of 5 on our list. It is classed as Seaweed / Marine Algae / Marine Botanicals. We have not found a published study that grades it, so treat this number as unconfirmed.
Sources we checked this rating against
- Kligman AM, Kwong T. “An improved rabbit ear model for assessing comedogenic substances.” British Journal of Dermatology, June 1979;100(6):699–702. (opens in a new tab) The rabbit-ear assay behind published 0 to 5 comedogenicity grades.
- Fulton JE Jr. “Comedogenicity and irritancy of commonly used ingredients in skin care products.” Journal of the Society of Cosmetic Chemists, November/December 1989;40(6):321–333. (opens in a new tab) Rabbit ear. Each ingredient at 10 percent in propylene glycol unless stated, applied five days a week for two weeks, and graded 0 to 5 from the width of the follicles, measured by micrometer and under the microscope. The paper counts 0 to 1 as not significant, 2 to 3 as borderline and 4 to 5 as positive. Some grades depended on the supplier of the raw material, and some oils were also tested refined.
- Draelos ZD, DiNardo JC. “A re-evaluation of the comedogenicity concept.” Journal of the American Academy of Dermatology, March 2006;54(3):507–512. doi:10.1016/j.jaad.2005.11.1058 (opens in a new tab) Tested finished products on the backs of six people and concluded that “Finished products using comedogenic ingredients are not necessarily comedogenic.”