What a 4/5 rating means
On the comedogenic scale, a 4 is in the high-risk band, with a real likelihood of clogging pores on acne-prone skin. That means Spirulina deserves attention if you break out easily, especially when it appears high on an ingredient list.
This rating is disputed. Credible sources land on different numbers for Spirulina, so we publish the range (4) rather than a false single figure. When sources disagree this openly, your own experience carries real weight.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so Spirulina near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About Spirulina
It is a marine or algae extract, marketed for minerals and antioxidants. A blue-green algae named on pore-clogging lists in the high range; data is limited and formula-dependent.
On a label it can read as Spirulina, Arthrospira Plantensis, Blue Green Algae, Blue Algae — worth knowing when you scan an ingredient deck.
Spirulina in makeup and skincare
It features in 'anti-ageing' serums, masks, and luxury complexion products. Its irritancy is rated separately at 2/5, which is low.
Lower-rated alternatives to Spirulina
If you want a similar role with a friendlier comedogenic score, consider:
- Hyaluronic Acid — comedogenic rating 0/5 (Low risk).
- Niacinamide — comedogenic rating 0/5 (Low risk).
Spirulina comedogenic FAQ
Is Spirulina comedogenic?
It can be. Spirulina is rated 4/5 (high risk) on the 0–5 comedogenic scale, so it has a real chance of clogging pores on acne-prone skin, especially high on an ingredient list. Sources disagree on Spirulina, so the rating is less settled than most.
What is the comedogenic rating of Spirulina?
Spirulina has a comedogenic rating of 4/5 (high risk). Of the 190 ingredients in our dataset with a published rating, 13 rate higher than Spirulina, 151 rate lower, and 25 others share its 4/5. Among the 7 rated marine and algae extracts, 2 rate higher and none lower. The figure is drawn from 1 cited source, listed on this page.
Is Spirulina pore-clogging?
It is one of the more likely ones. At 4/5, Spirulina is in the high-risk band. It matters most when it appears near the top of an ingredient list, where it makes up a larger share of the product. Comedogenic ratings come mostly from rabbit-ear assays and small human patch tests of the pure ingredient at high concentration, so they are a screening guide, not a prediction for your skin or a medical claim.