Astaxanthin
The red algal pigment that colours salmon, taken mostly for skin.
- Skin and sunlight
- Exercise and recovery
- Everyday antioxidant
- Memory and thinking
- Blood sugar and cholesterol
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
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On this page
What is astaxanthin?
Astaxanthin is the deep red pigment made by a green microalga, Haematococcus pluvialis, and it is the same pigment that colours trout, salmon and shrimp. Chemically it is a xanthophyll carotenoid, kin to the yellow and orange pigments in plants, though it carries keto and hydroxyl groups reviews call unusual. Most astaxanthin made in the world is a synthetic version for fish feed, and the algal kind sold to people is about one per cent of the market; reviews note the two are not chemically identical. It is sold as soft gels, capsules and oils, on its reputation as an antioxidant.
Why do people take astaxanthin?
Skin and sunlight
The thinking. Skin is the commonest reason people buy astaxanthin: dryness, fine lines, and how skin holds up to a summer of sun. The idea is that a pigment which soaks up reactive oxygen, and which reviews describe as settling inflammation, leaves less of the wear ultraviolet light does.
What research has found. Trials measure moisture in the outer layer, how far skin stretches and springs back, and the depth of lines. Two reviews of about a dozen small studies, most in Japanese adults at 3 to 6 mg a day, found moisture and elasticity better than a dummy capsule, while pooled wrinkle depth did not shift. One trial found skin reddened less readily under ultraviolet light. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Exercise and recovery
The thinking. Runners, cyclists and lifters take astaxanthin through a block of hard training, hoping to turn up fresher for the next session. Hard exercise raises markers of damage and inflammation in the blood, and the idea is that a daily antioxidant might take the edge off those, and tilt the body towards burning fat.
What research has found. A review of twenty-four randomised trials found two of those markers, creatine kinase and lactate dehydrogenase, lower after supplementing, while oxygen uptake, time trials and peak power were no different from a dummy capsule. An earlier review of eleven trials in 346 healthy adults reported better aerobic efficiency at 20 mg and above, and a week-long trial in twelve club cyclists took fifty seconds off a 40 km time trial. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.
An everyday antioxidant
The thinking. Plenty of people take astaxanthin for nothing in particular, on the strength of what it does in a test tube: reviews rank its antioxidant activity above other carotenoids and vitamins C and E. The thinking is that mopping up the reactive oxygen the body makes as it burns fuel leaves less wear behind.
What research has found. What gets measured here is blood, not how anyone feels. A review of fifteen human studies described inflammation signals falling and antioxidant capacity rising; a meta-analysis of twelve trials in 380 people found malondialdehyde, a sign of fat being oxidised, lower, most clearly in adults with type 2 diabetes, while C-reactive protein and tumour necrosis factor did not move. A year-long trial in adults after a kidney transplant found no difference in artery stiffness or those markers. Results here go both ways, which usually means the dose, the length of a trial or the group taking part makes the difference.
Memory and thinking
The thinking. Astaxanthin also sells to people who want to stay sharp as the years go on. Reviews of it cover the ageing brain among many other organs, and carotenoids as a group have been studied for memory because they are the antioxidants in fruit and vegetables. The thinking is the one running through this page: less reactive oxygen sitting in tissue.
What research has found. Only one review has gathered this up, and it found two astaxanthin trials to gather. One reported better recall of words in middle-aged adults, and the reviewers said two studies were too few to tell which way it pointed. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Blood sugar and cholesterol
The thinking. A smaller group takes astaxanthin with a blood test in mind, often after one came back borderline. Most of that research has been in adults carrying extra weight or living with type 2 diabetes, and the thinking is that settling oxidation and inflammation would show in the numbers.
What research has found. Two reviews pooled seven and fourteen trials between them. Neither found a change in fasting blood sugar, HbA1c, total cholesterol or blood pressure across the trials as a whole; one found LDL cholesterol lower, the other HDL cholesterol slightly higher at larger doses taken for longer. Individual trials in adults with type 2 diabetes, prediabetes and polycystic ovary syndrome did report lower fasting sugar and less insulin resistance. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.
What does astaxanthin do in the body?
Astaxanthin is a fat-soluble pigment, and what it does in the body is chemistry with oxygen. Ordinary breathing and burning fuel leave reactive oxygen behind, which over time damages what is around it. Astaxanthin quenches singlet oxygen, mops up peroxyl and hydroxyl radicals, turning them into steadier compounds, stops some free radicals forming at all, and interrupts the chain reaction by which oxidation spreads.
It also latches on to loose metal ions that would otherwise set oxidation going. Its shape is what makes it unusual: keto and hydroxyl groups on a long pigment backbone, which reviews say is what lets it work on oxygen as it does. That shape is also fragile: heat, light and acidity rearrange the molecule into different isomers, into clumps, or locked up as an ester, and those changes alter how much is absorbed and how active it is. It is also why the synthetic pigment made for fish feed cannot be assumed to behave like the algal one.
What do people say about taking astaxanthin?
These are anecdotes people have shared, not evidence.
What people like
- Skin is what people most often say they noticed themselves, several describing better condition while not having looked for it.
- Several describe taking it for a year or more with nothing to complain about, which is much of why they carry on.
- Many buy it as a general antioxidant rather than for one complaint, with sun and everyday wear what they mention.
- A couple noticed something they were not expecting, in training or in general energy, rather than the reason they started.
Common complaints
- Noticing nothing at all is the commonest complaint, reported after a month, after several years, and by people who tried twice.
- In one long-illness community several describe unexpected tiredness within hours of a dose, which may reflect that group more than the supplement.
- Those reporting tiredness were mostly on 12 mg capsules; some cut to a smaller dose or took it only on harder days.
- Odd single reports turn up, including dizziness in someone also taking fish oil, but no repeated pattern of stomach upset.
How people take it
- Two figures come up again and again, 4 mg and 12 mg, and several deliberately stay on the smaller one.
- Nearly everyone takes one soft gel once a day, and most describe it sitting inside a longer list of supplements.
- Fish oil, magnesium, ubiquinol and turmeric are most often mentioned alongside it, which makes any single effect hard to separate.
- Several give it about a month before judging, and one or two restarted at a lower dose rather than stopping.
Read from these public discussions:
- Anyone have problems with Astaxanthin? (Phoenix Rising ME/CFS Forums, 2012)
- Astaxanthin (Phoenix Rising ME/CFS Forums, 2014)
- Astaxanthin Supplements - Any Users? (HairLossTalk Forums, 2018)
- Astaxanthin and light sensitivity (Dry Eye Zone Forums, 2012)
- Please can I have all you anti ageing tips thrown this way...? (Mumsnet, 2017)
What forms of astaxanthin are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| Astaxanthin | A red xanthophyll carotenoid; labels name either the pigment itself or the microalga it is grown from. | not in our price tables yet |
What else is worth knowing about astaxanthin?
- A safety review of 87 human studies found none reporting safety concerns with the algal form, thirty-five of them at 12 mg a day or more. Approved daily amounts differ by country, from 2 mg to 24 mg, and the European figure of 2 mg rests on a study of the synthetic form.
- A review pooling five trials in 196 adults found one liver enzyme, ALT, around two units higher in the astaxanthin groups than in the comparison groups, with the other liver enzymes unchanged.
- Labels give the amount per serving, and a serving may be more than one soft gel. The trials here used 4 mg to 20 mg a day, most often 6 to 12 mg.
- Much of this research was in particular groups rather than in people with nothing wrong: adults with type 2 diabetes, women having fertility treatment, people after a kidney transplant, firefighters and trained cyclists.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (27 studies)
- Effects of Astaxanthin Supplementation on Skin Health: A Systematic Review of Clinical Studies. (2021, systematic review)
- Systematic Review and Meta-Analysis on the Effects of Astaxanthin on Human Skin Ageing. (2021, meta-analysis)
- The Protective Role of Astaxanthin for UV-Induced Skin Deterioration in Healthy People-A Randomized, Double-Blind, Placebo-Controlled Trial. (2018, randomised trial)
- Cosmetic benefits of astaxanthin on humans subjects. (2012, randomised trial)
- The Effects of Astaxanthin Supplementation on Exercise Recovery Biomarkers and Exercise Performance: A Systematic Review and Meta-Analysis. (2026, meta-analysis)
- Effects of Astaxanthin Supplementation on Fatigue, Motor Function and Cognition: A Meta-Analysis of Randomized Controlled Trials. (2024, meta-analysis)
- Impact of astaxanthin supplementation on markers of cardiometabolic health and tactical performance among firefighters. (2024, randomised trial)
- The effect of astaxanthin supplementation on performance and fat oxidation during a 40 km cycling time trial. (2021, randomised trial)
- The Role of Astaxanthin as an Antioxidant and Anti-Inflammatory Agent in Human Health: A Systematic Review. (2026, systematic review)
- Astaxanthin supplementation mildly reduced oxidative stress and inflammation biomarkers: a systematic review and meta-analysis of randomized controlled trials. (2022, meta-analysis)
- Randomized clinical trial of astaxanthin supplement on serum inflammatory markers and ER stress-apoptosis gene expression in PBMCs of women with PCOS. (2024, randomised trial)
- The antioxidant and anti-inflammatory effects of astaxanthin supplementation on the expression of miR-146a and miR-126 in patients with type 2 diabetes mellitus: A randomised, double-blind, placebo-controlled clinical trial. (2021, randomised trial)
- Effects of Astaxanthin Supplementation on Oxidative Stress. (2020, randomised trial)
- Astaxanthin has no effect on arterial stiffness, oxidative stress, or inflammation in renal transplant recipients: a randomized controlled trial (the XANTHIN trial). (2016, randomised trial)
- Effects of Lutein and Astaxanthin Intake on the Improvement of Cognitive Functions among Healthy Adults: A Systematic Review of Randomized Controlled Trials. (2020, systematic review)
- Astaxanthin Influence on Health Outcomes of Adults at Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis. (2022, meta-analysis)
- The effects of astaxanthin supplementation on obesity, blood pressure, CRP, glycemic biomarkers, and lipid profile: A meta-analysis of randomized controlled trials. (2020, meta-analysis)
- Astaxanthin supplementation impact on insulin resistance, lipid profile, blood pressure, and oxidative stress in polycystic ovary syndrome patients: A triple-blind randomized clinical trial. (2024, randomised trial)
- Astaxanthin Supplemented with High-Intensity Functional Training Decreases Adipokines Levels and Cardiovascular Risk Factors in Men with Obesity. (2023, randomised trial)
- The Beneficial Effects of Astaxanthin on Glucose Metabolism and Modified Low-Density Lipoprotein in Healthy Volunteers and Subjects with Prediabetes. (2021, randomised trial)
- Astaxanthin improves glucose metabolism and reduces blood pressure in patients with type 2 diabetes mellitus. (2018, randomised trial)
- Astaxanthin: sources, extraction, stability, biological activities and its commercial applications--a review. (2014, review)
- Recent progress in practical applications of a potential carotenoid astaxanthin in aquaculture industry: a review. (2024, review)
- Astaxanthin: A super antioxidant from microalgae and its therapeutic potential. (2022, review)
- Health benefits of astaxanthin against age-related diseases of multiple organs: A comprehensive review. (2023, review)
- Structures of Astaxanthin and Their Consequences for Therapeutic Application. (2020, review)
- Astaxanthin: How much is too much? A safety review. (2019, review)
How much does astaxanthin cost?
That depends on the form and the pack, so we work out the price of the same dose of every astaxanthin product we can find and rank them.