Astaxanthin is a red-pink pigment found in various seafoods, and also in the feathers of flamingos and quails. It is structurally similar to beta-carotene (pro-vitamin A) but has some chemical differences which may be safer. It seems to be able to improve many blood parameters that could be beneficial to heart disease. At doses of 6-8mg daily, it can decrease the oxidation of LDL cholesterol and prevent it from becoming artherogenic (artery clogging). It can increase general blood flow and reduce blood sugar in diabetics and blood pressure in spontaneously hypertensive rats (humans not studied yet) with no effect on these measures in normal healthy persons. Additionally, it is also a potent anti-inflammatory and has more anti-oxidant capabilities than vitamin A itself.
Astaxanthin appears to be recommended in the dosage range of 6-8mg daily, which is low enough that an enriched salmon oil or krill oil supplement may contain adequate levels. Doses of up to 20-50mg astaxanthin have been tolerated, although the exact toxicity and upper limit is not known. Despite the above recommendations, the ideal dose of astaxanthin is currently not known. Due to being a carotenoid, and related to the metabolism of Vitamin A (a fat soluble vitamin) it would be prudent to take astaxanthin alongside a meal.