Astaxanthin (pronounced “asta-ZAN-thin”) is a deep red-orange marine carotenoid pigment that occurs naturally in salmon, Pacific and Antarctic krill, rainbow trout, lobster, yeast, microalgae, Arctic shrimp and other sea creatures. Astaxanthin is considered one of the most powerful naturally-occurring antioxidants and has been called a “Master Antioxidant” and “King of the Carotenoids”, due to its superlative potential for free radical scavenging in the human body.
Carotenoids have gained much attention in recent years due to their beneficial effects on human health. Around 750 carotenoids have been identified and researched and they are most typically known for their antioxidant and anti-inflammatory effects. 
In 2007 scientists ran tests to determine the “singlet oxygen quenching rate constants” (antioxidant ability) for numerous dietary antioxidants. This, in simple language, indicates their potential as free radical scavengers. The results were astounding. 
Astaxanthin was found to be a much more powerful antioxidant than β‐carotene, α‐tocopherol, lycopene, lutein and other members of the carotenoid family. The study found astaxanthin 6,067x stronger than vitamin C (L-Ascorbic acid), 794x stronger than CoQ10 (ubiquinone), 562x stronger than green tea catechins (Epigallocatechingallate), 75x stronger than alpha lipoic acid and 40x stronger than β‐carotene! Astaxanthin in fact “beat all comers” including curcumin, resveratrol, lycopene, zeaxanthin and lutein.
However unlike β‐carotene and lycopene, Astaxanthin can cross the blood–brain and blood–retinal barriers, and so may exert its positive effects on the brain and eyes.
Astaxanthin For Eye Health:
Astaxanthin As Neuroprotective And Cognition Enhancer:
Most of the neurological benefits provided by seafood consumption are regarded as deriving from omega-3 and omega-6 polyunsaturated fatty acids and antioxidants. However studies of astaxanthin have demonstrated results against free radical-promoted neurodegenerative processes and cognition loss.  It has the capability to cross the blood-brain barrier and is receiving attention for its effect on the prevention or co-treatment of neurological pathologies, including Alzheimer and Parkinson diseases.  Recent study has also found that astaxanthin ameliorates cognitive impairment in cases of “chemobrain” – a condition experienced by a high proportion of cancer patients given chemotherapeutic treatment.  A 12-week study found both high dosage (12mg) and low dosage (6mg) improved cognitive health scores in 96 middle-aged and elderly test subjects. 
Sources And Production Of Astaxanthin:
Astaxanthin is produced both naturally and through chemical synthesis; thus if you are seeking a natural form, be sure to specify this when purchasing.
Astaxhanthin has been approved as a feed ingredient for salmon and contributes to the color of farmed salmon. It is generally recognized as safe (GRAS) and in the EU it has the food additive number E161j. 
Most of the astaxanthin which is used for aquaculture is produced synthetically; however natural, GMO-free astaxanthin is available in supplement form. Natural-source astaxanthin is typically isolated from microorganisms. The fast-growing microalga Haematococcus pluvialis is the primary source for natural astaxanthin production and is thought to contain the highest level found in nature, with 40g of astaxanthin being obtained from one dry kilogram of the microalga. Other microorganism sources include the yeast Phaffia rhodozyma and the appropriately named gram-negative aerobic bacterium Paracoccus carotinifaciens. 
Digging further into this to learn whether GMO techniques are used, I found the GRAS application of one manufacturer who reported that while a mutant strain of P. carotinifaciens was used for the production of the astaxanthin, this was developed “using classical mutation and selection techniques and has not been subjected to genetic engineering.”  The inference here, however, is that GMO techniques may be used either now or at some point in the future and thus the buyer should be fully aware of the source in order to make an informed choice.
How To Take Astaxanthin:
Astaxanthin occurs in small quantities in salmon, krill, crayfish and shrimp but in order to achieve its full therapeutic potential, supplements are generally recommended.
165 grams (5.8 ounces) of wild salmon daily would be required in order to get a 3.6 milligram dose, which is considered beneficial to health. Now I love salmon but to match this you would have to chomp through an unreasonable amount of wild salmon, 7 days per week – and the quantity of astaxanthin in farmed Atlantic salmon is lower still. 
Dosage: A typical one-a-day astaxanthin supplement might contain 1.5 to 9mg. Studies  have tested 12mg per day in 96 subjects for 12 weeks without note of adverse effects. One study gave a single 100mg dose to three volunteers – with food. Plasma concentration peaked at 6.7 +/- 1.2 hours and after 72 hours, 12% remained. Side effects were not noted. 
Like CoQ10, astaxanthin is lipid-soluble thus best taken with food in order to facilitate optimal uptake. Taking astaxanthin with fish oil has been found to provide increased benefits in terms of antioxidant, immune response and infectious disease risk reduction characteristics. 
The usual caveat applies: This article is not a medical recommendation. Ask your Doctor before using supplements, especially if you are using medications.
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