Marine ingredients seem to turn up everywhere. It seems that there is a potion or lotion with seaweed or algae. They are so ubiquitous that they are danger of becoming passe. It struck me, after Aerwin made a comment on the La Mer post about whether seaweed was really an antiager, that the fad would be over before I truly understood whether it had had any merit. And what's the difference between seaweed and algae.

Actually, not much. Both seaweed and algae seem to be fairly vague terms. Seaweed is a loose colloquial term encompassing macroscopic, multicellular, benthic marine algae, according to Wikipedia. The term includes some members of the red, brown and green algae.

Seaweed may seem to be the cosmetic industry's new black, but it has actually been used forever in the form of something called carrageenan, a humble thickener and stabilizer usually extracted from a seaweed called chondrus crispus. Carrageenan is also used as a food additive and as such has been found to be carcinogenic in a study on rats. Happily, this only happens when the carrageenan is broken down by acids in the stomach and topical application is perfectly safe.

There are four seaweeds commonly used in Chinese medicine and some of them also turn up in beauty products. Laminaria is a kelp and  a brown algae. Ecklonia is a green algae. Sargassum is another brown alga an pyrphora is a red algae.

Seaweed is a powerful ingredient as it draws an extraordinary wealth of mineral elements from the sea that can account for up to 36% of its dry mass. These include sodium, calcium, magnesium, potassium, chlorine, sulfur and phosphorus; the micronutrients include iodine, iron, zinc, copper, selenium, molybdenum, fluoride, manganese, boron, nickel and cobalt.

As far as iodine is concerned, the highest content is found in brown algae, with dry kelp ranging from 1500-8000 ppm (parts per million). Daily adult requirements, currently recommended at 150 µg/day, could be covered by very small quantities of seaweed as just one gram of dried brown algae provides from 500-8,000 µg of iodine.

Recently, seaweed has emerged as a potent antioixidant. Researchers at the University of Ohio found that brown algae applied topically and orally reduced the number of skin tumors on hairless mice by up to 60 percent and their size by up to 43 percent. It also reduced inflammation.

Bladderwrack is a seaweed that has a high amount of vitamin C. There is also alginic acid, which is insoluble in water and swells by absorbing water up to 100 times its weight. As a result, bladderwrack is used in treatments for cellulite.

According to Dermaxime, a cosmetic company,  laminaria digitata, or Atlantic kelp, is rich in compounds that are of specific use in the cosmetic industry, such as polygalactosides, fucose polymers and ursolic acid. Polygalactosides react with the protective outer surface of the skin to form a protective moisturizing complex, while the fucose polymers are hygroscopic and act as hydrating agents. The ursolic acid can help form a protective barrier on the skin. I wasn't able to corroborate these claims with another source.

New algae are being discovered all the time. For example, the Amala skincare range uses something called lola implexa, an Antarctican alga that was only discovered in 2008. Perhaps because it is so new, there is barely any information about it. Meanwhile, a university team in the UK that thinks it has found the ultimate safe, non-chemical hair dye in seaweed.

Hailed as the next wonder anti-aging ingredient, phytessence wakame is derived from an exotic kelp (actually a sea algae) native to the sea of Japan. Belonging to the phaeophycae laminariales plant family, phytessence wakame is said to have immune-stimulating, cancer preventing, anti-inflammatory, and anti-allergic properties. Himanthalia elongata extract comes from a species of brown seaweed which has small button-like, perennial thalli. It’s known to provide high levels of vitamins A, C and E along with essential amino acids and other natural minerals, and is used in many skin care products thanks to its natural ability to help restore balance to skin’s moisture levels.