What is it?
An extract of Laminaria digitata, a dark brown kelp up to 2 meters long with a blade split into finger-like segments, which grows on rocks along North Atlantic coasts, from the low-tide zone into shallow water. Like other kelps it is rich in alginic acid and other sugars, minerals and iodine. In cosmetics the extract is used as a skin-protecting and skin-conditioning ingredient, and sometimes as a fragrance ingredient.
Key information
- The CIR Expert Panel concluded in 2019 that Laminaria Digitata Extract is safe in cosmetics as currently used.
- Human tests of products with up to 12 percent Laminaria digitata extract found no skin sensitization.
- Laminaria digitata is among the brown algae the FDA lists as generally recognized as safe (GRAS) in food.
- Like other seaweeds it can contain arsenic, heavy metals and iodine, which manufacturers are expected to control.
More information
Suppliers told the Cosmetic Ingredient Review (CIR) that they make Laminaria digitata extracts by washing, drying or grinding the harvested seaweed and extracting it with water, water and propylene glycol, or caprylic/capric triglyceride; one extract is broken down with enzymes into short sugar chains. In 2019 FDA data, Laminaria Digitata Extract was the most used brown algae ingredient, in 310 products, and the dried powder was reported at up to 40 percent in face and neck products. Laminaria digitata is also a food: the FDA lists it among brown algae generally recognized as safe (GRAS) as a flavor enhancer.
In 2019 the CIR Expert Panel reviewed 82 brown algae ingredients and concluded that 68 of them, including Laminaria Digitata Extract and Laminaria Digitata Powder, are safe in the present practices of use and concentration. Human sensitization tests of products with up to 12 percent Laminaria digitata extract were negative. In one human irritation test, a trade mixture of the extract in water and propylene glycol caused moderate irritation after 30 minutes that had eased to slight irritation by 24 hours; most other brown algae irritation tests were negative.
Brown seaweeds take up arsenic and heavy metals from seawater, and the Panel asked manufacturers to keep these impurities low through good manufacturing practice. Laminaria digitata is also especially high in iodine, 0.75 to 1.2 percent of its dry weight in late autumn and winter; the Panel noted iodine concerns from seaweed supplements but judged that exposure from cosmetics would be far lower. On labels, look for Laminaria Digitata Extract or Laminaria Digitata Powder.
Sources: CIR: Safety Assessment of Brown Algae-Derived Ingredients as Used in Cosmetics (final report, 2019); Legal Information Institute: 21 CFR 184.1120, Brown algae