Astaxanthin

We evaluated 139 human studies on Astaxanthin, including 54 randomised controlled trials and 32 meta-analyses or systematic reviews; the controlled studies include 2,957 participants in total. As of 5 October 2026.

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1. What Is Astaxanthin? Occurrence, Origin and Forms

Astaxanthin is a red carotenoid of the xanthophyll group. It gives marine animals such as crabs, shrimp and salmon, as well as flamingo feathers, their pink to red colour. It is sold as a dietary supplement in capsules, and in aquaculture it is used to pigment farmed fish.

Astaxanthin is formed in microalgae, above all in Haematococcus pluvialis, and in yeasts such as Xanthophyllomyces dendrorhous. Through the food chain it accumulates in krill, shrimp, crabs and salmon; in humans it is studied as a dietary supplement.

For study material, astaxanthin is mostly obtained from cultivated Haematococcus pluvialis algae, and also from yeast fermentation and chemical synthesis. What is tested are oil-based capsules with esterified or free astaxanthin, algal extracts, and occasionally preparations applied to the skin.

Forms and Preparations Studied

• Algal extract from Haematococcus pluvialis
• Astaxanthin from yeast fermentation
• Synthetically produced astaxanthin
• Esterified astaxanthin in an oil carrier
• Free astaxanthin
• Preparation for application to the skin

Not covered on this page:

• Krill oil and fish oil as a whole: they contain astaxanthin but are mixtures of omega-3 fatty acids and further substances.
• Other carotenoids such as beta-carotene, lutein, zeaxanthin and lycopene.
• Canthaxanthin, a different carotenoid that is likewise used for pigmentation.
• Astaxanthin as a feed additive in aquaculture when humans are not the subjects studied.

2. What Does Astaxanthin Do? Results by Area

How to read the table: counted are human studies whose results concern the area. “High” means at least one meta-analysis and two controlled studies showing improvement, or at least three controlled studies of which three quarters show improvement, with at least 300 participants in total. “Moderate” means at least two controlled studies showing improvement, as a majority, or one meta-analysis alongside controlled studies. “Low” means one controlled study showing improvement. Where an area has no controlled study, the strength of evidence is at most “low” (result “reviews only” or “observational data only”). Everything else is “unclear”. A study counts as showing improvement when at least half of its outcomes in this area improved. Reviews of combination products do not count as meta-analyses; results that only describe side effects or shares of users do not count as an effect. The same study is counted only once.

3. What the Studies Show in Detail

Astaxanthin, Oxidative Stress and Inflammation: Human Studies

Compared with placebo, malondialdehyde, a marker of lipid peroxidation, fell more strongly in two randomized studies: in heart failure and after exhaustive cycling 3875. In the heart failure study, total antioxidant capacity and superoxide dismutase also rose more strongly than under placebo 38. In women with PCOS, catalase and total antioxidant capacity rose more strongly than under placebo, while malondialdehyde and superoxide dismutase did not 76. In type 2 diabetes under metformin, superoxide dismutase and catalase rose more strongly than under placebo, while malondialdehyde did not differ 55. Another randomized study found no difference from placebo for malondialdehyde 73, and a meta-analysis classifies the antioxidant effect overall as unclear 27. Inflammatory markers fell more strongly than under placebo in two randomized studies: TNF-α in heart failure 36, interleukin-6 and TNF-α in pneumonia 37. C-reactive protein fell in a meta-analysis only with a higher dose or longer intake 29. With dark chocolate in lycosome form, malondialdehyde and oxidized LDL fell more markedly than with astaxanthin alone 65. It remains open in which patient groups and at which doses the effect occurs reliably; this requires larger studies with uniform measures.

Further studies in this area: 14 21 22 27 29 35 36 37 38 42 45 46 48 49 51 53 54 55 56 57 61 63 66 68 72 73 75 76 77 78 79 82 90 95 102 103 104 105 107 108 109 110 112 115 116 118 119 121 126 127 128

Astaxanthin and Cardiometabolic Markers: Human Studies

In prediabetes and type 2 diabetes, astaxanthin lowered fasting blood glucose, HbA1c, triglycerides, total and LDL cholesterol and raised HDL cholesterol compared with control in a meta-analysis 2. In type 2 diabetes, two randomized studies with the same design found lower blood glucose, HbA1c and blood lipid levels than under placebo 5152. In women with PCOS, fasting blood glucose, insulin resistance and LDL cholesterol decreased in a placebo-controlled study, while HDL cholesterol increased 48. In coronary heart disease, however, blood glucose levels did not differ from placebo 54. For blood lipids, the meta-analyses are inconsistent: HDL cholesterol increased in three of them 21529. LDL cholesterol decreased in two reviews 25, while three others found no effect on LDL and total cholesterol 61529. Body weight and body mass index did not change in two meta-analyses 219. Combinations with red yeast rice, berberine, policosanol, folic acid and coenzyme Q10 lowered LDL cholesterol, also in addition to a statin; this does not allow any statement about astaxanthin alone 3032. It remains open whether the better laboratory values translate into fewer cardiovascular events; studies with such endpoints are still pending.

Further studies in this area: 21 25 29 30 35 36 38 42 43 44 47 48 49 51 54 62 67 85 89 95 102 108 109 110 118 123 127 128

Astaxanthin, Exercise and Physical Performance: Human Studies

The most consistent finding is on recovery: in a meta-analysis of randomized studies, creatine kinase, a marker of muscle damage, was lower after exertion than under placebo 10. Randomized studies showed the same in young soccer players and after exhaustive cycling 6675. For performance, the meta-analyses are inconsistent: one found better physical performance when taken together with training 4. A larger meta-analysis, by contrast, found no improvement in maximum oxygen uptake, time trial performance or maximum performance 10. In small randomized studies with cyclists, astaxanthin shortened the time trial time and lengthened the time to exhaustion 7475. In older nursing home residents, the walking distance in the six-minute walk test was greater than under placebo 82. Fat burning during cycling was higher than under placebo in two randomized studies 7174, but not in another 73. An algal extract with astaxanthin and lutein did not reduce muscle damage after strength training 83; a crossover study with strength athletes also found no difference from placebo 85. It remains open whether the better recovery values translate into noticeably faster regeneration.

Further studies in this area: 73 74 75 82 83 84 85 94 95 110 117 121 124

Astaxanthin and Skin: Human Studies

In a small randomized study, skin tolerated more UV light until redness and lost less moisture when irradiated under astaxanthin than under placebo 69. In a placebo-controlled study with women in Japan, wrinkles and skin moisture worsened over the autumn months only under placebo, not under astaxanthin 79. Suspicion: A systematic review sees advantages for skin structure, wrinkles, moisture and UV protection; many of the included studies were small and company-funded 26. A combination with collagen hydrolysate improved elasticity and water loss of facial skin compared with placebo, but does not allow any statement about astaxanthin alone 80. It remains open whether the protective effect is confirmed in larger studies and outside Japan.

Further studies in this area: 116 118

Astaxanthin and Cognition: Human Studies

In healthy older adults with forgetfulness, individual cognitive tests improved with Haematococcus algae extract, without a confirmed difference from placebo 34. A meta-analysis found no effect on reaction time and only a borderline effect on cognitive accuracy 4. Clearer advantages over placebo were shown by combinations: with tocotrienols for memory 59, with Bacopa, lycopene and vitamin B12 in the Trail-Making Test and for verbal fluency 40. In athletically active young women, after mental fatigue, reaction time and speed in two tasks improved only with astaxanthin, not with placebo 81. Hypothesis: A review of older people sees indications of better cognition that are not statistically confirmed 23. For astaxanthin alone, larger studies with memory tests as the primary aim are needed.

Further studies in this area: 113 116 118

Astaxanthin and Eyes: Human Studies

In schoolchildren with eye strain from screens, astaxanthin in a randomized study reduced complaints and visual fatigue more than placebo; visual acuity and accommodation did not change 45. A mixture with anthocyanin and lutein improved pupil response and focusing complaints in adults with screen fatigue compared with placebo 58. In dry eye, an antioxidant mixture with anthocyanosides, vitamins and herbal extracts improved the overall impression compared with placebo, but sicca complaints did not differ 60. Without a comparison group, in people of middle and older age with dry eye, complaints and tear film stability improved under algae extract from Haematococcus pluvialis 91. It remains open whether the findings of the mixtures are due to astaxanthin or to the combination partners.

Astaxanthin, Tolerability and Safety: Human Studies

Under astaxanthin alone, in controlled studies neither side effects nor differences in safety values compared with placebo were noted 34454988. In pneumonia, astaxanthin as an addition to standard therapy was safe and well tolerated 37. Two systematic reviews report no serious adverse events or notable laboratory findings 2326. Mixed preparations with astaxanthin, for example with krill oil and hyaluronic acid or with red yeast rice and berberine, were also well tolerated 3133. Data on intake for more than a few months are still pending.

Further studies in this area: 78 88 92 96 102 122 123 127 128

Astaxanthin: Further Outcomes in Studies

In women with PCOS before artificial fertilization, the proportion of mature eggs was higher than under placebo in two randomized studies 5676. In one of them, the proportion of high-quality embryos also increased 76. A meta-analysis confirms the higher maturation proportion; pregnancy rates did not differ either there or in the randomized study 2276. In men with impaired sperm quality, astaxanthin did not change any semen parameter in a randomized study 39. In rheumatoid arthritis, disease activity fell more than under placebo 46, in pneumonia, severity scores improved in addition to standard therapy 37. In knee or hip osteoarthritis, a mixed preparation of krill oil, astaxanthin and hyaluronic acid relieved joint pain more than placebo 31. These findings each come from individual small studies and need independent replication.

Further studies in this area: 22 24 36 37 38 39 46 50 53 54 56 70 76 86 87 88 90 92 94 97 98 99 103 104 108 109 110 116 118 120 125 129

4. How Is Astaxanthin Dosed? Preparation, Dose and Duration in Studies

The studies used predominantly oral astaxanthin capsules, some with algal extract from Haematococcus pluvialis or extract from Paracoccus carotinifaciens, some without stated origin. Individual investigations tested combination preparations, for example with lutein, tocotrienols, krill oil, collagen or dark chocolate. Origin and esterification of the astaxanthin are not reported in many studies; the doses are shown in the table.

5. Is Astaxanthin Safe? Side Effects in Studies

In placebo-controlled studies with astaxanthin alone, no side effects or differences in safety values were observed 344549. In a study on a combination preparation of krill oil, astaxanthin and hyaluronic acid, fewer participants reported adverse events than under placebo; gastrointestinal complaints were most common in both groups 31. Long-term data are still pending, because the studies were mostly small and lasted from a few weeks to months.

6. What Remains Open: Limits of the Evidence

• Origin and esterification of the astaxanthin are not reported in many studies; which form is most effective remains open.
• Many controlled studies are small and short, which limits the transferability of the results.
• Some of the findings come from combination preparations and do not allow any statement about astaxanthin alone.
• Most findings concern blood and measured values; for clinical endpoints such as pregnancy rate, the studies found no difference.

7. Bottom Line: What Is Established About Astaxanthin

Astaxanthin is a carotenoid from the xanthophyll group that is offered as a dietary supplement in capsules. The clearest evidence is for higher HDL cholesterol and less muscle damage after exertion, and in prediabetes and diabetes also for better blood glucose levels. For oxidative stress, the results are inconsistent; for skin, eyes and memory, the evidence comes from small studies and partly from combination preparations. Meta-analyses showed no effect on body weight, maximum oxygen uptake and reaction time. The findings apply to the preparations studied, mostly capsules, often with algal extract from Haematococcus pluvialis; combination preparations do not allow any statement about astaxanthin alone. Next, larger and longer studies with clearly described preparations are needed that also capture clinical endpoints.