The giant of the seas: a seaweed that grows up to half a metre a day and forms underwater forests 45 metres tall.

What is kelp?

“Kelp” is the name of the large brown seaweeds of the order Laminariales. Giant kelp (Macrocystis pyrifera) is the largest seaweed in the world: it anchors to the seabed and rises towards the surface buoyed by small air bladders. Its extract is rich in minerals from seawater — iodine, magnesium, potassium, calcium — as well as alginates, fucoidan and other polysaccharides, amino acids and vitamins.

What are the benefits of kelp?

Seaweed brings the sea into skin care. Applied topically it:

• Offers the minerals and trace elements of the sea
• Its polysaccharides hold moisture on the surface of the skin
• Leaves the skin soft and hydrated
• Gives a revitalising feel
• Suits normal, combination and tired skin

Forests of the sea

Kelp forests are among the most productive ecosystems on the planet, home to otters, seals and hundreds of species of fish. Darwin, in Tierra del Fuego in 1834, wrote that their destruction would be more devastating to life than the loss of a forest on land. In Scotland and Brittany the ash of seaweed was for centuries a raw material for soap and glass, and it was in this ash that iodine was discovered in 1811.

Where does it come from?

Giant kelp grows in the cold, nutrient-rich waters of the Pacific — off the coasts of California, Chile, New Zealand and southern Australia. It is harvested by cutting the upper part, so that the seaweed grows back.