Astaxanthin (as’ tä zan’ thin) is the main carotenoid pigment found in aquatic animals – particularly in krill, shrimps and salmonid fish. This red-orange pigment is closely related to other well-known carotenoids such as beta-carotene or lutein but has been found to have a stronger antioxidant activity (10 times higher than beta-carotene). Studies suggest that astaxanthin can be 500 to 1000 times more effective as an antioxidant than vitamin E.[1]

In many of the aquatic animals where it can be found, astaxanthin has a number of essential biological functions, ranging from protection against oxidation of essential polyunsaturated fatty acids, protection against UV-light, pro-vitamin A activity and vision, immune response, pigmentation, and communication, to reproductive behavior and improved reproduction.[2] Some of these unique properties of astaxanthin have also been found to be effective in humans as well.[3],[4],[5],[6]

Crustaceans and other aquatic animals (as well as mammals) are unable to produce astaxanthin. This means it must be acquired from the diet as is the case with other carotenoids. Only plants and protists (bacteria, algae, fungi) are capable of synthesizing carotenoids. Therefore astaxanthin must be available in either their native habitat or manufactured diet to meet metabolic nutritional requirements. In the natural aquatic environment, astaxanthin is biosynthesized in the food chain within microalgae or phytoplankton. A micro-algae called Haematococcus pluvialis is believed to be the organism which can accumulate the highest levels of astaxanthin in nature.[7],[8]

Astaxanthin can be found in many of our favorite seafoods such as salmon, trout, red seabream, shrimp, and fish eggs.2 Therefore, including these foods in your diet will increase your intake of this powerhouse antioxidant. There are two forms of astaxanthin, free and esterified. The esterified seems to be more stable and is believed to be an adaptive feature to allow storage of astaxanthin in tissues.[9]

Astaxanthin Sources – Mixed Free and Esterified

  • Sockeye salmon (26-37 mg/kg)
  • Coho salmon (9-21 mg/kg)
  • Chum salmon (3-8 mg/kg)
  • Chinook salmon (8-9 mg/kg)
  • Pink salmon (4-6 mg/kg)
  • Atlantic salmon (3-11 mg)
  • Rainbow trout (1-3 mg/kg)
  • Synthetic astaxanthin  (80,000 mg/kg – fed to farmed animals;100% free form)

Astaxanthin Sources – Predominantly Esterified

  • Salmon eggs (0-14 mg/kg)
  • Red seabream (2-14 mg/kg)
  • Red seabream eggs (3-8 mg/kg)
  • Peneaus monodon (10-150 mg/kg)
  • Krill (46-130 mg/kg)
  • Krill oil (727 mg/kg)
  • Crayfish meal (137 mg/kg)
  • Artic shrimp (1160 mg/kg)
  • Yeast (Pfaffia r.) (30-800 mg/kg)
  • Haematococcus pluvialis (10,000-30,000 mg/kg)

A few companies are beginning to manufacture astaxanthin in supplement form. Most of the recent development involves the micro-algae Haematococcus pluvialis. Remember, consume a variety of seafood to naturally increase your consumption of this powerhouse antioxidant.


[1] Jyonouchi, H., L. Zhang, M. Gross, and Y. Tomita. 1994. Immunomodulating actions of carotenoids: Enhancement of in vivo and in vitro antibody production to T-dependent antigens. Nutr. Cancer 21: 47-58.

[2] Black, H. 1998. Radical interception by carotenoids and effects on UV carcinogenesis. Nutr. Cancer 31: 212-217.

[3] DiMascio, P., T.P.A. Devasagayam, S. Kaiser, and H. Sies. 1990. Carotenoids, tocopherols and thiols as biological singlet molecular oxygen quenchers. Trans. Biochem. Soc. 18: 1054-1056.

[4] Gradelet, S., P. Astorg, J. LeClerc, J. Chevalier, M.-F. Vernevaut, and M.-H. Siess. 1996. Effects of canthaxanthin, astaxanthin, lycopene and lutein on liver xenobiotic-metabolizing enzymes in the rat. Xenobiotica 26: 49-63.

[5] Jyonouchi, H., R.J. Hill, Y. Tomita, and R. A. Good. 1991. Studies of immunomodulating actions of carotenoids. I. Effects of beta-carotene and astaxanthin on murine lymphocyte functions and cell surface marker expression in in vitro culture system. Nutr. Cancer 16: 93-105.

[6] Jyonouchi, H., L. Zhang, and Y. Tomita. 1993. Studies of immunomodulating actions of carotenoids. II. Astaxanthin enhances in vitro antibody production to T-dependent antigens without facilitating polyclonal B-cell activation. Nutr. Cancer 19: 269-280.

[7] Kurashige, M., E. Okimasu, M. Inoue, and K. Utsumi. 1990. Inhibition of oxidative injury of biological membranes by astaxanthin. Physiol. Chem. Phys. & Med. NMR 22: 27-38.

[8] Miki, W., K. Hosada, K. Kondo, and H. Itakura. 1998. Astaxanthin-containing drink. Japanese Patent #10155459 [in Japanese].

[9] Miki W. 1991. Biological functions and activities of animal carotenoids. Appl. Chem., 63(1), 141-146.