Norwegian kelp (Ascophyllum nodosum) is a brown seaweed found in the North Atlantic basin. It grows in long, strap-like fronds on the sheltered sides of intertidal rocks, and is sustainably harvested in Iceland, Norway and Ireland. Use includes for food, biotechnology, cosmetics, high-quality animal meal and agricultural fertilizer. When used in skincare, it is said to soothe irritation and boost cell renewal.

Other names for this seaweed include rockweed, knotted wrack, knotted kelp or egg wrack.