Possible concerns
Reputable sites mention that the claimed benefits rest on limited animal, in-vitro or weak human studies. Web md claims 4 oz of red sockeye provide 4.5 mg of A-X
WebMD: "Some laboratory studies have shown astaxanthin may hinder an enzyme called
5-alpha-reductase. As a result, it could keep testosterone from changing into the hormone DHT in the body. It's unclear what effect this may have, but prescription medicines that affect the same enzyme may cause side effects, such as: lower libido, gyno, ED"
Berkeley Wellness was the only review site I found that gave A-X a "not recommended rating" based upon the study showing beta carotene supplementation can increase cancer risk in smokers. Their abundance of caution based upon inference and association to being similar to carotene might seem lame to many.
Bekeley Welleness supplement evaluation pub Oct 2011;
http://www.berkeleywellness.com/supplements/other-supplements/article/astaxanthin-hype
"In a nutshell "not recommended" ( 2011) . "decreased male libido and gyno"
Again, no citations and based on inference. Never heard of anyone getting ED or any health problems from eating sockeye or drinking iced flamingo feather tea.
"a handful of human studies show AX reduces c-reactive protein" ???
"Natural Standard, Berkeley goes on to say, gives AX a 'C' rating:
"unclear or conflicting evidence—for its use for high cholesterol, male infertility, muscle strength, musculoskeletal injuries, carpal tunnel, and rheumatoid arthritis. There's limited or no research at all to support its use for eye problems, asthma, dementia, exercise capacity, sunburn protection, or other conditions for which it's promoted." ( as of 2010)
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I will look for studies newer than 2010-2011 and report back here.
