Antioxidants are compounds that stop the oxidation of sensitive molecules in the body. They quench the activity of free radicals – unstable compounds that can damage cells. Excessive quantity of free radicals, relative to antioxidants, causes oxidative stress. Many factors may cause this to happen, including disease, pollution or poor lifestyle habits. The body has its own antioxidant defenses, but nutrients like vitamin E, vitamin C and astaxanthin also function as antioxidants.
While astaxanthin is not essential in people’s diet, it can strengthen the body’s defenses and protect against oxidative stress. Astaxanthin’s antioxidant effects are, in some ways, stronger than those of other carotenoids and vitamin E (1, 2, 3). Many studies have investigated the antioxidant effects of astaxanthin supplements in people. Most of the time, their results have been very promising. A controlled study in overweight adults showed that taking 20 mg of astaxanthin daily for three months increased the total antioxidant capacity of the blood by 35%. The supplements also raised the levels of superoxide dismutase, one of the body’s main antioxidants, by 30%. These improvements were associated with a 33% decrease in the circulating levels of malondialdehyde (MDA) and a 59% reduction in the levels of isoprostane (4). Both MDA and isoprostane are indicators of lipid peroxidation, which is the oxidative breakdown of lipids caused by free radicals.
Supporting these findings, studies have confirmed that astaxanthin has direct effects on lipid peroxidation in cell membranes. One study in middle-aged and older people found that taking 6 or 20 mg of astaxanthin for three months significantly reduced the levels of peroxidized lipids in red blood cells, relative to a placebo (5). Another two-week study found that taking astaxanthin in doses that gradually increased from 1.8 to 21.6 mg daily decreased low-density lipoprotein (LDL) oxidation, whereas no such changes occurred in the control group (6). Underlining this, a study in healthy Finnish men found that taking 4 mg of astaxanthin per day for three months significantly reduced the circulating levels of oxidized fatty acids (7). And in young, healthy women, taking a daily dose of 8 mg of astaxanthin for two months reduced an indicator of DNA damage (8). Simply put, many studies demonstrate the powerful antioxidant effects of astaxanthin, even at low doses.