Algae and Men
  Sources and Uses of Commercial Algae
    - Food
      - Cyanophyta
      - Rhodophyta 
      - Heterokontophyta
      - Chlorophyta
    - Extracts 
      - Agar
      - Alginate 
      - Carrageenan
    - Animal Feed
    - Fertilizers 
    - Cosmetics 
    - Therapeutic Supplements 
    - Toxin
Extract of algae is often found on the list of ingredients on cosmetic packages, particularly in face, hand, and body creams or lotions, but the use of algae themselves in cosmetics, rather than extracts of them, is rather limited.

Milled macroalgae, packed in sachets, is sold as an additive to bath water, sometimes with essential oils added. Bath salts with macroalgae meal are also sold. Thalassotherapy has come into fashion in recent years, especially in France. In thalassotherapy, macroalgae pastes, made by cold-grinding or freeze-crushing, are applied to the person’s body and then warmed under infrared radiation. This treatment, in conjunction with seawater hydrotherapy, is said to provide relief for rheumatism and osteoporosis. Mineral-rich seawater is used in a range of therapies, including hydrotherapy, massage, and a variety of marine mud and algae treatments. One of the treatments is to cover a person’s body with a paste of fine particles of macroalgae, sometimes wrap them in cling wrap, and warm the body with infrared lamps.

It is said to be useful in various ways, including relief of rheumatic pain or the removal of cellulite. Paste mixtures are also used in massage creams, with promises to rapidly restore elasticity and suppleness to the skin. The macroalgae pastes are made by freeze grinding or crushing. The macroalgae is washed, cleaned, and then frozen in slabs. The slabs are either pressed against a grinding wheel or crushed, sometimes with additional freezing with liquid nitrogen that makes the frozen material more brittle and easier to grind or crush. The result is a fine green paste of macroalgae.

There appears to be no shortage of products with ingredients and claims linked to macroalgae: creams, face masks, shampoos, body gels, bath salts, and even a do-it-yourself body wrap kit. The efficacy of these products must be judged by the user. A company recently pointed out that the lifetime of cosmetic products has reduced over the years and now rarely exceeds 3 or 4 years. Perhaps the macroalgae products that are really effective will live longer than this.

Cosmetic products, such as creams and lotions, sometimes show on their labels that the contents include “marine extract,” “extract of alga,” “macroalgae extract” or similar. This usually means that one of the hydrocolloids extracted from macroalgae has been added. Alginate or carrageenan could improve the skin moisture retention properties of the product.