Astaxanthin side effects are rare and generally mild when this supplement is used appropriately. Astaxanthin is a pigmented carotenoid which is considered a GRAS (generally regarded as safe) food ingredient by the US FDA.
Astaxanthin is used as a food coloring and feed additive for the production of eggs, chicken, trout, salmon, shrimp and crabs.
This compound is also found naturally in Krill Oil supplements and is now available as a single-ingredient anti-oxidant supplement Astaxanthin is used for age-related macular degeneration, certain neurodegenerative diseases, stroke, hypercholesterolemia and certain types of cancer.
It has also been implicated for improving other conditions including male infertility, menopause symptoms, carpal tunnel syndrome, muscle soreness, rheumatoid arthritis and wrinkled skin.
Most users experience no adverse astaxanthin side effects. More research on its benefits and dangers is warranted.



- Antioxidant and immune booster
- Supports cardiovascular health
- Shown to improve cholesterol levels
Astaxanthin Safety Ratings
Related Topics
According to the Natural Medicines database, astaxanthin is likely safe when taken orally in common dietary amounts. It is considered possibly safe when used alone and in oral doses between 4 and 40 mg daily. These dosage levels have demonstrated safety when used for up to 12 weeks.
When astaxanthin has been used along with other substances (like certain vitamins, minerals and/or other carotenoids), 4 mg daily doses have caused no adverse effects for up to one year.
There is not enough information about astaxanthin side effects and safety to rate its uses in pregnant or nursing women. Usage should be avoided unless instructed to use this supplement by a qualified physician.
Astaxanthin Side Effects
Adverse reactions to oral astaxanthin administration are not common. However, certain cardiovascular, dermatologic (skin), endocrine (hormonal), gastrointestinal, genitourinary (genitals plus urinary organs), hematologic (blood-based), ocular (vision) and/or psychiatric side effects are possible.
Research on astaxanthin cardiovascular side effects is limited. Animal research studies have shown it to decrease blood pressure in some cases. For this reason, it is best to speak to your doctor before using astaxanthin capsules if you have low blood pressure.
Astaxanthin can inhibit 5-alpha-reductase enzymes which modulate steroid metabolism, androgen metabolism, estrogen metabolism and bile acid biosynthesis.
Inhibiting 5-alpha-reductase is known to reduce the conversion of testosterone to dihydrotestosterone (DHT). This could potential result in side effects or drug interactions. However, there have not been any reported incidents in research studies conducted to date.
Astaxanthin dermatologic side effects may include increasing hair growth and/or skin pigmentation. Other adverse effects which may potentially result from inhibiting 5-alpha-reductase include:
- Decreased quantity of semen during ejaculation;
- Decreased sex drive (libido);
- Impotence;
- Gynecomastia (male breast growth);
- Depressed moods;
Risk of Potential Side Effects
Other possibilities for endocrine-based astaxanthin side effects include gaining weight and/or losing muscle mass. As stated earlier, these side effects have not been observed in human research trials but are theorized as possibilities based on observed mechanisms of action.
Certain gastrointestinal side effects are possible with astaxanthin administration. In research addressing the effects of astaxanthin for treating functional dyspepsia, severe abdominal pain was experienced in two separate cases. This may be related to the dosage use.
Hematologic astaxanthin side effects have not been well studied. However, canthaxanthin, another pigmented carotenoid which is structurally similar to astaxanthin, has been linked to a singular case of aplastic anemia.
Aplastic anemia is a condition in which the body slows production of new blood cells. This often leads to feelings of fatigue and/or increased bleeding risks. In other research studies, astaxanthin caused decreases in eosinophil (stained white blood cells) levels.
Ocular astaxanthin side effects have not been reported. However, canthaxanthin has demonstrated a theoretical potential to cause vision damage via the formation of calcium crystals inside the eyes.
Astaxanthin Toxicity Data
In animal research sponsored by Mera Pharmaceuticals, data was reported concerning the toxicity of AstaFactor®, an astaxanthin dietary supplement. AstaFactor® is derived from a green microalgae called Haematococcus pluvialis.
In nature, Haematococcus pluvialis is the most concentrated source of astaxanthin. 0.5 and 50 mg/kg doses of H. pluvialis algal meal were fed to rats over 28 days. No subacute markers of toxicity were noted.
In other animal research, a solution of distilled water and Haematococcus pluvialis algal meal was tested. Single doses between 10,417 and 18,000 mg/kg caused no deaths or abnormalities.
In research addressing acute toxicity potentials, the median lethal dose (LD50) of astaxanthin was determined to be greater than 5000 mg/kg of bodyweight.
Mera Pharmaceuticals also conducted limited human research concerning the toxic effects of AstaFactor®. All subjects were volunteers.
One group received 228 mg doses of algal meal, containing 3.85 mg of astaxanthin each. Another group received 1140 mg doses of the meal which contained 19.25 mg of astaxanthin each. These doses were delivered daily over 29 days. No astaxanthin side effects or signs of toxicity were noted.
Astaxanthin Drug Interactions
There are no known interactions between astaxanthin and drugs and/or herbal supplements.
Taking other carotenoids in conjunction with astaxanthin may reduce its absorption inside the gastrointestinal tract. Keep this in mind if using astaxanthin with beta-carotene, lutein, canthaxanthin, lycopene and/or certain other similar substances.
Food sources of carotenoids may also affect the absorption of astaxanthin. There are more than 600 known carotenoids. They are commonly found in numerous vegetables, fruits and other foods. Carrots and tomatoes are two of the most concentrated natural sources.
There are no reported adverse interactions between astaxanthin and diseases or laboratory tests.
Conclusions
Astaxanthin side effects are rare and generally unlikely. Astaxanthin demonstrates multiple therapeutic potentials and may alter the functioning of certain body systems. Speak with your doctor about the safety and possible benefits of astaxanthin usage.
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Article last updated on: March 13th, 2018 by Nootriment
2 Comments
Known as the Kig of Carotenoids and as nature’s most powerful antioxidant astaxanthin works to reduce inflammatory compounds that drive many chronic diseases, making it a very potent natural anti-inflammatory. Without all the nasty side effects of prescription anti-inflammatories, Astaxanthin works to reduce inflammation throughout the body by controlling free radicals and cell damage.
I use it and i highly encourage people to use it.
Been taking High doses for nearly a month now (around 40-60 mg though its powder so dont know exactly) The main thing ive noticed is my skin is gettin really health looking. I used it mixed with water after gettin a little sunburnt and it seems to have completely healed within 2 days and i havnt burnt at all since despite still gettin sun on me.