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7 Astaxanthin Benefits

Written by Carlos Tello, PhD (Molecular Biology) | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Carlos Tello, PhD (Molecular Biology) | Last updated:

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Astaxanthin is a red pigment found in fish, shrimp, and some microalgae. It is a potent antioxidant that may help with skin aging, cardiovascular risks, protect the brain, and modulate the immune system. Read this post to learn more about the potential benefits of astaxanthin and how it may help optimize your health.

What Is Astaxanthin?

Astaxanthin (AST) is a naturally-occurring orange-red pigment carotenoid found in algae, shrimp, lobster, crab, and salmon.

Astaxanthin is made by the green microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum, as well as by the yeast Phaffia rhodozyma [1].

The green algae H. pluvialis make high amounts of this antioxidant pigment when exposed to unfavorable conditions (such as high UV exposure) to reduce the damage from free radicals [2].

Animals that eat these microalgae or yeast take up astaxanthin. This explains why wild shrimp, lobster, crab, and salmon have bright red-orange colors. Wild salmon can contain up to 26-38 mg of astaxanthin per kg of body weight, whereas farmed Atlantic salmons typically have only 6-8 mg [3, 1].

Although it is also a carotenoid, astaxanthin is not converted to vitamin A in the human body. Like other carotenoids, astaxanthin has self-limited oral absorption. Very high doses (up to 465 mg/kg/day for male and 557 mg/kg/day for female) caused no toxicity signs in rats [4, 5].

However, overconsumption of astaxanthin can turn animal skin and tissues red, which is why astaxanthin is used in feed for farmed seafood and fish [3].

Pharmacokinetics

Astaxanthin is a highly fat-soluble substance, which means that it is better absorbed when consumed with fat [6].

When astaxanthin is ingested, it is digested and absorbed in a similar manner as fat (it is assembled into chylomicrons). The chylomicrons are absorbed into lymph circulation before remnants of astaxanthin are digested by lipoprotein lipases. Astaxanthin is then assimilated into lipoprotein particles to get transported into tissues [7].

This means astaxanthin can more readily affect the metabolism of fat and cholesterol, especially when it relates to cardiovascular health.

In rats, ingested astaxanthin was metabolized by first-pass liver metabolism primarily by the CYP450 enzyme [8].

Astaxanthin has been identified in most tissues, but not in the heart [8].

Snapshot

Proponents

  • Antioxidant and immunomodulatory
  • May protect the skin
  • May help with exercise fatigue
  • May reduce the risk of heart disease
  • May protect the brain
  • Few adverse effects reported

Skeptics

  • Insufficient evidence for most benefits

Benefits

As an antioxidant, astaxanthin is 10 times stronger than zeaxanthin, lutein and beta-carotene, and 100 times stronger than vitamin E [9, 10].

The structure of astaxanthin allows it to enter cell membranes or stay outside of cell membranes, allowing it to protect cell membranes from both inside and outside the cell [11].

Possibly Evidence for:

Skin Aging

In a small trial on 30 women and 36 men, a treatment combining oral and topical astaxanthin reduced wrinkles and age spots while improving skin elasticity, texture, and moisture. Oral astaxanthin alone had similar effects in another trial on 34 middle-aged people [12, 13].

Supplementing with astaxanthin and collagen hydrolyzate improved skin elasticity and integrity while reducing the production of 2 proteins that break down collagen (MMP-1 and MMP-12) in response to UV radiation in a clinical trial on 44 healthy people. In another trial on 23 people, oral astaxanthin reduced skin redness and loss of moisture after UV irradiation while improving its texture [14, 15].

In mice, astaxanthin prevented skin thickening, collagen reduction, and melanin production in response to UV [16].

In skin cells exposed to UVA radiation, astaxanthin reduced the induced production of 2 proteins that break down collagen (MMP-1 and SFE/NEP) and a pro-inflammatory cytokine (IL-6). This suggests that astaxanthin could protect against UVA-induced skin photoaging such as sagging and wrinkles [17].

Although limited, the existing evidence suggests that astaxanthin may protect the skin from aging and UV radiation. You may discuss with your doctor if it may be useful as a complementary approach in your case.

Insufficient Evidence for:

1) Reducing Exercise Fatigue

In a small trial on 21 cyclists, oral astaxanthin improved power output and time trial performance [18].

In a clinical trial on 40 male soccer players, oral astaxanthin improved the antioxidant status by increasing the activity of an antioxidant enzyme (PON1). Similarly, another trial on 32 male soccer players found that supplementation with astaxanthin improved antioxidant status and reduced muscle damage after exercise [19, 20].

However, two trials on 64 well-trained male cyclists found that supplementation with astaxanthin didn’t improve antioxidant status, fat use, and exercise performance. In addition, astaxanthin failed to reduce muscle damage after exercise in another trial on 20 well-trained people [21, 22, 23].

The antioxidant effects of astaxanthin significantly delayed exhaustion in a forced swimming test in rats [24].

In dogs, eating a protein bar with astaxanthin immediately after physical exercise increased glycogen and protein production, thus helping replenish their energy stores [25].

A few small clinical trials (with mixed results) and some animal research are insufficient to claim that astaxanthin reduces exercise fatigue. Larger, more robust clinical trials are needed to shed some light on this potential benefit.

2) Reducing the Risk of Heart Disease

In a clinical trial on 27 overweight people, supplementation with astaxanthin lowered “bad” cholesterol (LDL and ApoB) and oxidative damage, possibly reducing the risk of clogged arteries. Similarly, oral astaxanthin reduced LDL oxidation in a clinical trial on 20 healthy volunteers [26, 27].

In another trial on 61 people with mildly high blood fat levels, astaxanthin reduced triglycerides while increasing “good” HDL cholesterol and a protein that promotes fat breakdown (adiponectin) [28].

In mice, astaxanthin delayed and reduced blood clotting in the blood vessels, while increasing blood flow [29].

In rats, rabbits, and dogs, pre-treatment with synthetic astaxanthin reduced the damage caused by heart attacks in heart tissues [30, 31, 32].

Blood isolated from 20 people given astaxanthin showed reduced blood clotting markers, suggesting it may help prevent heart disease from blood clots [33].

Although the results are promising, 3 clinical trials and some animal research cannot be considered sufficient evidence to attest to the potential ability of astaxanthin to prevent heart disease. More clinical trials on larger populations are needed.

3) Cognitive Function

In 2 clinical trials on 45 people, supplementation with the antioxidants astaxanthin and sesamin reduced mental fatigue and improved cognitive functions related to the ability to comprehend and perform complex tasks quickly and accurately (psychomotor and processing speed) [34, 35].

Astaxanthin improved the antioxidant status of red blood cells in a small trial on 30 middle-aged and elderly people. This resulted in a reduced buildup of oxidized fats (phospholipid hydroperoxides) in their cell membranes, which is a risk factor for developing dementia [36].

In rats, it delayed brain aging by reducing oxidative damage and increasing the levels of a protein that promotes the birth of new brain cells (BDNF) [37].

Pre-treatment with high doses (80 mg/kg) of astaxanthin significantly reduced brain damage from a stroke in rats [38].

Mice pre-treated with astaxanthin performed better in a learning performance test after a stroke. Similarly, it reduced brain swelling and sped up recovery after a traumatic brain injury in mice [39, 40, 41].

Astaxanthin protected brain cells from beta-amyloid-induced toxicity, suggesting it may protect against Alzheimer’s disease [42, 43].

Again, only 3 clinical trials (two of which combined astaxanthin with sesamin) and some animal and cell-based research have been conducted. More clinical research is needed to confirm these preliminary results.

4) Diabetes

In a clinical trial on 44 people with type 2 diabetes, supplementation with astaxanthin for 8 weeks improved blood sugar control (measured as reduced fructosamine and glucose levels), improved blood fat profile, and lowered blood pressure [44].

Similarly, astaxanthin improved insulin sensitivity in rats and mice on high-fat and high-sugar diets [45, 46].

Generally, high blood sugar causes high levels of oxidative stress in diabetic patients. Astaxanthin can protect pancreatic β-cells (which produce insulin) from oxidative stress caused by high blood sugar, as seen in diabetic mice [47].

It also reduced cell damage due to glucose-induced oxidative stress in brain and kidney cells, suggesting it may prevent diabetic neuropathy and nephropathy [48, 49, 50].

A single clinical trial and some animal and cell-based research cannot be considered sufficient evidence that astaxanthin improves diabetes. Further clinical research is needed.

5) Fatty Liver Disease

In a pilot trial on 12 people with non-alcoholic fatty liver disease, supplementation with astaxanthin had no effect on liver function or sugar and fat metabolism, but it reduced fat buildup in the liver [51].

In the same study, astaxanthin was more effective than vitamin E at preventing and improving fatty liver in mice fed a high-fat diet. It reduced fat buildup, liver inflammation, and tissue scar [51].

A very small clinical trial and a study in mice are clearly insufficient to claim that astaxanthin improves liver disease. Further clinical trials on larger populations are needed to confirm these preliminary findings.

6) Modulating the Immune Responses

Supplementation with 2 mg astaxanthin for 8 weeks enhanced immune response and reduced the production of an inflammatory marker (CRP) in a clinical trial on 42 young healthy women [52].

Astaxanthin supplementation enhanced antibody production and decreased immune response in older animals [48].

Combined astaxanthin and fish oil supplementation modulated lymphocyte function in rats [53].

Again, only one clinical trial and some animal studies have been carried out. More research in humans is needed to draw conclusions on the potential effects of astaxanthin on the immune function.

Animal and Cell Research (Lack of Evidence)

No clinical evidence supports the use of astaxanthin for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies should not be interpreted as supportive of any health benefit.

Stomach Ulcers

Cell extracts of Haematococcus and Chlorococcum significantly reduced the number of H. pylori and stomach inflammation in H. pylori-infected mice [54, 55].

Mice pretreated with astaxanthin before ulcer induction had significantly fewer stomach ulcers [56].

Cancer

Below, we will discuss some preliminary research on astaxanthin’s potential anticancer effects. It’s still in the animal and cell stage and further clinical studies have yet to determine if its extract may be useful in cancer therapies.

Do not under any circumstances attempt to replace conventional cancer therapies with magnolia bark or any other supplements. If you want to use it as a supportive measure, talk to your doctor to avoid any unexpected interactions.

In rats and mice with chemically-induced mouth, bladder, colon, breast, and soft tissue cancer, astaxanthin inhibited tumor formation and growth [57, 58, 59, 60, 61].

In cell-based studies, astaxanthin inhibited the growth of colon, fibrosarcoma, breast, and prostate cancer cells and embryonic fibroblasts by activating tumor-suppressor genes such as p53 [48].

Side Effects & Dosage

Side Effects

Keep in mind that the safety profile of astaxanthin is relatively unknown, given the lack of well-designed clinical studies. The list of side effects below is not a definite one and you should consult your doctor about other potential side effects based on your health condition and possible drug or supplement interactions.

Astaxanthin is considered likely safe when ingested in food doses and possibly safe when consumed as a supplement.

In a clinical trial, a few adverse effects such as cold, diarrhea, and dizziness were observed. However, their frequency was similar in the treatment and placebo groups [35].

Dosage

Because astaxanthin is not approved by the FDA for any condition, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor if astaxanthin may be useful as a complementary approach in your case and which dose you should take.

Beneficial results have been observed at 2 mg in humans with dose-dependent effects at 8 mg [52].

No signs of toxicity were found at very high doses (over 500 mg/kg of body weight) in mice [4, 5].

About the Author

Carlos Tello

Carlos Tello

PhD (Molecular Biology)
Carlos received his PhD and MS from the Universidad de Sevilla.
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.

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