What is Ascophyllum Nodosum (Knotted Wrack)?
Ascophyllum Nodosum (Knotted Wrack) (INCI name: Ascophyllum Nodosum Extract) is a marine or algae-derived extract. A brown seaweed extract grouped with the high-rated marine ingredients on pore-clogging lists.
You may see it on labels as Ascophyllum Nodosum, Ascophyllum Nodosum Extract, Ascophyllum, Bladderwrack, so it can hide under more than one name in an ingredient list.
Where Ascophyllum Nodosum (Knotted Wrack) shows up
You'll most often find Ascophyllum Nodosum (Knotted Wrack) in anti-ageing serums, masks, and 'marine' or 'seaweed' branded skincare. Separately from clogging, its irritancy is rated 2/5 — low, so it's unlikely to sting or sensitise on its own.
Is Ascophyllum Nodosum (Knotted Wrack) bad for acne-prone skin?
On acne-prone skin, Ascophyllum Nodosum (Knotted Wrack) has a real chance of contributing to congestion. Check its position on the ingredient list before you worry — concentration changes everything.
Worth flagging: Ascophyllum Nodosum (Knotted Wrack)'s rating is disputed. Credible sources land on different numbers, which is why we show a range rather than a single score — and why your own experience is the best tiebreaker.
Non-comedogenic alternatives
If you're avoiding Ascophyllum Nodosum (Knotted Wrack), these lower-risk ingredients serve a similar role and are gentler on pore-prone skin:
- Hyaluronic Acid — rated 0/5 (Low risk).
- Niacinamide — rated 0/5 (Low risk).