Vitamins & Supplements · Antioxidant
Astaxanthin
Astaxanthin (C40H52O4) · also called Astaxantina
Astaxanthin is a red-pink antioxidant pigment, mostly sold as a supplement made from algae. Small trials found better skin moisture and lower muscle-damage markers, but the evidence is low-certainty and often company-funded. Reviews found no clear gain for tiredness, thinking or performance. It has a good safety record in short studies, though liver enzymes and blood thinners need a doctor or pharmacist.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Astaxanthin
Astaxanthin is a red-pink pigment made by algae. It is sold as an antioxidant supplement. Small trials show some skin and exercise-marker changes, and no large trials show a health benefit.
What astaxanthin is
Astaxanthin is a xanthophyll carotenoid, a red-pink pigment related to beta-carotene. A 2021 review describes it as derived from the microalga Haematococcus pluvialis, and another review says it is found in bacteria and microalgae. It can also be made chemically, and the 2019 safety review says the synthetic form is chemically different from the natural one.
It is not an essential nutrient: the body does not need it to stay healthy. Krill oil, an omega-3 product, contains astaxanthin and has its own page.
Where astaxanthin comes from
Supplements and food ingredients are mostly made from cultivated Haematococcus pluvialis algae. EFSA describes an algal meal (about 5% astaxanthin) and an oleoresin extract (about 10%). Amounts of astaxanthin per portion of seafood were not found in USDA or NIH sources in this build, so none are given here.
What the research shows
The best-supported results are for skin: a 2021 meta-analysis found better moisture and elasticity, though not fewer wrinkles. A 2026 review of 24 exercise trials found lower muscle-damage markers but no gain in VO2max, time-trial or power. Results for oxidative stress and inflammation markers are mixed.
Evidence is thin or insufficient for tiredness, thinking, cholesterol and blood pressure, and for eye strain in children, where one company-linked trial exists. No trial read shows that astaxanthin prevents or treats a disease.
Most trials were small, short, in healthy people (often Japanese women), and many were funded by companies that make astaxanthin.
Natural versus synthetic, and food versus pills
Most trials used capsules, and many abstracts do not say whether the astaxanthin came from algae. Safety findings for natural astaxanthin should not be applied to the synthetic form. No trial compared eating astaxanthin-rich foods with taking pills.
At a glance
Traditional uses history, not proof
- A pigment found in algae and some seafood
- Sold as an antioxidant supplement for skin and exercise
Studied for research
- Skin moisture and elasticity, low certainty
- Oxidative stress markers, mixed
- Exercise recovery markers, low certainty
- Exercise performance, mixed
- Cholesterol and blood pressure, low certainty
- Digital eye strain in children, very low certainty
- Skin response to UV and inflammation markers, very low or insufficient
- Fatigue and thinking, insufficient
Main compounds
- Astaxanthin (natural, from Haematococcus pluvialis algae)
- Synthetic astaxanthin
Common forms
- Algal meal and algal oleoresin
- Capsules and soft gels
- Krill oil (contains astaxanthin)
Research links: 2021 meta-analysis: astaxanthin and skin ageing · 2022 meta-analysis: oxidative stress and inflammation markers · 2026 meta-analysis: exercise recovery and performance (24 trials) · 2019 safety review: how much is too much · 2024 meta-analysis: liver enzymes · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Astaxanthin (a red-pink carotenoid pigment, C40H52O4)
- Synonyms
- 3,3'-dihydroxy-beta,beta-carotene-4,4'-dione
- Common names
- Astaxanthin (English); Astaxantina (Spanish)
- Family or group
- A xanthophyll carotenoid. A 2021 review describes it as a xanthophyll carotenoid derived from the microalga Haematococcus pluvialis; a second review says astaxanthin is found in bacteria and microalgae.
- Harvest and processing
- EFSA describes algal meal (homogenised, crushed and spray-dried algal biomass, about 5% astaxanthin) and oleoresin (supercritical CO2 extract, about 10% astaxanthin).
- Look-alikes and adulterants
- Name: Krill oil; Note: An omega-3 oil that contains astaxanthin; it has its own page.; Name: Other carotenoids (lutein, zeaxanthin, lycopene, beta-carotene); Note: Related pigments with their own pages; astaxanthin is a different molecule.; Name: Synthetic astaxanthin; Note: Made chemically; the 2019 safety review says it is chemically different from the natural form.
- Sustainability and conservation
- Not assessed.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Astaxanthin PubChem 5281224 | xanthophyll carotenoid | EFSA: algal meal about 5% astaxanthin; oleoresin about 10%. | The studied active ingredient. Natural astaxanthin from Haematococcus pluvialis is used in most human studies read. 14 5 4 | Human data |
| Synthetic astaxanthin | xanthophyll carotenoid | Not read from a source. | Chemically different from the natural form, per the 2019 safety review. Few safety studies in people. 2 | Animal research |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Antioxidant activity | Not specified in the abstracts | Abstracts describe astaxanthin as an antioxidant and anti-inflammatory carotenoid, based on lab and animal studies. Human trials show only changes in blood markers such as malondialdehyde. 11 10 14 | Lab animal |
| Skin protection against UV | Not specified | A 2018 trial found a higher UV dose was needed to redden skin after astaxanthin. The mechanism was not shown. 7 | Human data |
Absorption, metabolism and elimination
- Absorption
- Not read in the abstracts.
- Distribution
- Not read.
- Metabolism
- Not read.
- Elimination
- Not read.
- Bioavailability
- Not read. Product forms (algal meal, oleoresin, oil capsules) were not compared in the sources read.
Isolated compounds versus whole extracts
Astaxanthin comes as an algal meal, an oleoresin, a synthetic compound, krill oil and as a pigment in some seafood. The trials read mostly used capsules, and some abstracts do not say whether the source was algae. The natural and synthetic forms are chemically different, and safety results for one should not be applied to the other. No trial compared food with pills.
Nutritional composition
Astaxanthin is not an essential nutrient. Food amounts per portion (for example in salmon, trout or shrimp) were not found in USDA or NIH sources in this build, so none are stated.
2 mixed findings3 low certainty2 very low certainty2 not enough evidence
What was looked at
The 9 benefits and uses checked for Astaxanthin, each with how strong the evidence is. Tap one to open it.
- Oxidative stress blood markersMixed findings
- Skin moisture and elasticityLow certainty
- Skin response to UV lightVery low certainty
- Inflammation blood markersNot enough evidence
- Exercise recovery blood markersLow certainty
- Exercise performanceMixed findings
- Fatigue and thinkingNot enough evidence
- Digital eye strain in childrenVery low certainty
- Cholesterol and blood pressureLow certainty
Lab markers tracked in the studies
Malondialdehyde (MDA)Interleukin-6 (IL-6)C-reactive protein (CRP) and TNF-alphaCreatine kinase (CK)Lactate dehydrogenase (LDH)LDL cholesterol
What is Astaxanthin good for?
The main studied uses and how strong the human evidence is for each. Most results are blood markers or questionnaires in healthy adults.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Oxidative stress blood markers
Mixed findingsA 2022 review of 12 trials (380 people) found lower blood malondialdehyde, a marker of oxidative damage, with astaxanthin than with placebo. A 2026 review of 24 exercise trials found no significant change in malondialdehyde. A lower marker is not proof of better health.
2 studiesOral astaxanthin supplements; forms and amounts varied. Trial amounts…
Studies, doses and limits
What the trials found
The 2022 meta-analysis pooled 12 randomised trials (380 people, astaxanthin for at least a week versus placebo). Malondialdehyde was lower (SMD -0.95, 95% CI -1.67 to -0.23). The fall was also seen in people with type 2 diabetes (SMD -0.64). Superoxide dismutase activity and isoprostane (in overweight people) improved in a few trials. The 2026 meta-analysis of 24 exercise trials in healthy people and athletes found no significant effect on malondialdehyde.
Results
Mixed. Malondialdehyde was lower overall in 2022, but not in exercise trials in 2026. Neither review shows that this protects against any disease.
Effect sizes as reported
Malondialdehyde SMD -0.95 (-1.67 to -0.23) in 12 trials. Exercise trials 2026: no significant effect.
Why this rating
Mixed: one review finds a lower marker, a later review in exercisers does not, and the trials differ in product, people and length. Markers are not health outcomes.
Form and dose studied
Oral astaxanthin supplements; forms and amounts varied. Trial amounts are in the studies table only.
Who was studied
Adults, including people with type 2 diabetes, overweight adults, healthy people and athletes.
Limits
Few trials per marker. Authors of the 2022 review call the effect mild. Funding is not stated in the abstracts.
Why researchers looked
Astaxanthin is sold as an antioxidant, so researchers measure blood markers of oxidative damage.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Preliminary mechanism
Lab and animal studies suggest astaxanthin acts as an antioxidant. Human trials measure markers only.
A proposed mechanism does not show that the effect happens in people.
No safety signal for this outcome; see the Safety tab for liver enzymes.
Skin moisture and elasticity
Low certaintyA 2021 meta-analysis of randomised trials found oral astaxanthin improved skin moisture and elasticity more than placebo. Wrinkle depth did not change significantly. Most studies were small, in healthy Japanese women, and many were funded by companies.
2 studiesOral astaxanthin, mostly from algae. Trial amounts are in the studies…
Studies, doses and limits
What the trials found
The 2021 meta-analysis (Nutrients) pooled 9 randomised trials of oral astaxanthin from Haematococcus pluvialis microalgae. Moisture was higher (SMD 0.53, 95% CI 0.05 to 1.01; I2 52%) and elasticity was higher (SMD 0.77, 0.19 to 1.35; I2 75%). Wrinkle depth was not significantly lower (SMD -0.26, -0.58 to 0.06). A separate 2021 systematic review of 11 studies (6 randomised) found improvements in texture, appearance and moisture in many randomised trials and no serious adverse events, but warned the studies were small, mostly in healthy Japanese women, and often funded by commercial companies.
Results
Small gains in moisture and elasticity in healthy adults, mostly women. No clear effect on wrinkles. Findings need larger, independent trials.
Effect sizes as reported
Moisture SMD 0.53; elasticity SMD 0.77; wrinkle depth SMD -0.26, not significant.
Why this rating
Low: small trials, moderate to high differences between trials, and commercial funding in many.
Form and dose studied
Oral astaxanthin, mostly from algae. Trial amounts are in the studies table only.
Who was studied
Mostly healthy Japanese women.
Limits
Small samples; one population; commercial funding; the wrinkle result was not significant. Open-label topical studies were not pooled.
Why researchers looked
Astaxanthin is marketed for skin ageing, so trials measured moisture, elasticity and wrinkles.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Preliminary mechanism
Animal and lab studies suggest astaxanthin acts as an antioxidant in skin. This was not shown to be the reason for the human results.
A proposed mechanism does not show that the effect happens in people.
No serious adverse events were reported in these studies.
Skin response to UV light
Very low certaintyIn one 10-week trial of 23 healthy people, the astaxanthin group needed more UV light to redden their skin than the placebo group. The trial was small and sponsored by the product maker. It does not replace sunscreen or shade.
2 studiesA single-product capsule; amounts are in the studies table only.
Studies, doses and limits
What the trials found
A randomised, double-blind trial gave 23 healthy Japanese adults either a capsule with 4 mg of astaxanthin or placebo for 10 weeks. After 9 weeks, the astaxanthin group had a higher minimal erythema dose (the UV amount that reddens skin), less loss of skin moisture in the irradiated area, and better self-rated rough skin and texture in unexposed areas. The abstract gives no numbers.
Results
Promising in one tiny trial; not confirmed.
Effect sizes as reported
No numbers in the abstract.
Why this rating
Very low: one trial of 23 people, funded by the maker of the product, with no numbers in the abstract.
Form and dose studied
A single-product capsule; amounts are in the studies table only.
Who was studied
Healthy Japanese adults.
Limits
Single small sponsored trial. Not a substitute for sun protection.
Why researchers looked
Because astaxanthin is sold for sun-related skin ageing, one trial tested UV reddening.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Preliminary mechanism
Animal and lab studies suggest astaxanthin acts as an antioxidant in skin. This was not shown to be the reason for the human results.
A proposed mechanism does not show that the effect happens in people.
No safety findings in the abstract.
Inflammation blood markers
Not enough evidenceA 2022 meta-analysis found interleukin-6 was lower with astaxanthin in people with type 2 diabetes. CRP and TNF-alpha did not change significantly. A 2026 review of exercise trials found no significant change in IL-6. Evidence of a real health effect is insufficient.
3 studiesOral astaxanthin supplements; amounts are in the studies table only.
Studies, doses and limits
What the trials found
The 2022 meta-analysis found IL-6 lower in type 2 diabetes (-0.70 pg/mL, 95% CI -1.29 to -0.11), with no significant effect on CRP or TNF-alpha. The 2026 exercise meta-analysis found no significant effect on IL-6. A 2026 systematic review of mixed human studies reports lower inflammatory cytokines (IL-6, TNF-alpha, TGF-beta1) but gathers very different studies without a pooled analysis in the abstract, so it counts for little here.
Results
Marker changes appear in some groups only (type 2 diabetes). No health benefit shown.
Effect sizes as reported
IL-6 in type 2 diabetes -0.70 pg/mL (-1.29 to -0.11). CRP and TNF-alpha: not significant.
Why this rating
Insufficient: results differ between groups and reviews, and no trial shows that lower markers improve health.
Form and dose studied
Oral astaxanthin supplements; amounts are in the studies table only.
Who was studied
Adults with type 2 diabetes, healthy people and athletes.
Limits
The 2026 systematic review mixes very different studies. Markers are not health outcomes.
Why researchers looked
Antioxidants are often marketed for inflammation, so trials measure blood inflammation markers.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Preliminary mechanism
Lab and animal studies suggest astaxanthin lowers inflammation signals. This was not shown in people to affect health.
A proposed mechanism does not show that the effect happens in people.
No safety signal for this outcome.
Exercise recovery blood markers
Low certaintyA 2026 review of 24 trials in healthy people and athletes found lower creatine kinase (a muscle-damage marker) and lower lactate dehydrogenase with astaxanthin. The lactate dehydrogenase result varied a lot between trials. Lower markers did not come with better performance.
1 studiesOral astaxanthin supplements; amounts and lengths varied.
Studies, doses and limits
What the trials found
The 2026 meta-analysis (Nutrients) pooled 24 randomised trials of oral astaxanthin versus placebo or control in healthy participants and athletes. Creatine kinase was lower (SMD -0.45, 95% CI -0.83 to -0.07). Lactate dehydrogenase was lower (SMD -0.93, -1.39 to -0.48) with large differences between trials. Malondialdehyde and IL-6 did not change significantly. The authors say creatine kinase is the most consistent finding and the lactate dehydrogenase result should be read with caution.
Results
Some muscle-damage markers were lower. This is not the same as feeling or performing better.
Effect sizes as reported
Creatine kinase SMD -0.45 (-0.83 to -0.07); lactate dehydrogenase SMD -0.93 (-1.39 to -0.48).
Why this rating
Low: marker results only, big differences between trials for one marker, and different exercise plans.
Form and dose studied
Oral astaxanthin supplements; amounts and lengths varied.
Who was studied
Healthy adults and athletes.
Limits
Different exercise protocols and outcome measures. Funding is not stated in the abstract.
Why researchers looked
Athletes use antioxidants hoping to recover faster, so trials measure blood markers of muscle damage.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Not established
The 2026 review describes astaxanthin as a fat-soluble carotenoid with antioxidant and anti-inflammatory properties. How it might lower these markers in people was not tested.
A proposed mechanism does not show that the effect happens in people.
No safety signal for this outcome.
Exercise performance
Mixed findingsReviews disagree. A 2026 review of 24 trials found no significant gain in VO2max, time-trial performance or maximal power. A 2024 review of 11 trials found better physical performance when astaxanthin was combined with regular training. Evidence is mixed and not established.
2 studiesOral astaxanthin supplements; amounts and lengths varied.
Studies, doses and limits
What the trials found
The 2026 meta-analysis (24 trials) found no significant improvement in VO2max, time-trial performance or maximal workload. The 2024 meta-analysis (11 trials, 346 healthy people) found that with regular training astaxanthin was linked to higher fat oxidation (SMD 2.56, 95% CI 1.24 to 3.89) and better physical performance (SMD 0.62, 0.17 to 1.06), mainly in aerobic exercise. The two reviews cover overlapping but not identical trials.
Results
Mixed. One review sees a training-related gain, the larger and newer review sees no gain in direct performance tests.
Effect sizes as reported
2026: VO2max, time-trial and power not significant. 2024: physical performance SMD 0.62 (0.17 to 1.06).
Why this rating
Mixed: the reviews reach different conclusions and trial designs differ a lot.
Form and dose studied
Oral astaxanthin supplements; amounts and lengths varied.
Who was studied
Healthy adults and athletes.
Limits
Small trials. The authors of the 2026 review ask for standardised dosing, duration and exercise protocols.
Why researchers looked
Astaxanthin is sold to athletes for endurance, so trials measured fitness and performance.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Not established
The reviews describe astaxanthin as an antioxidant. No source read shows how, or whether, it changes exercise performance.
A proposed mechanism does not show that the effect happens in people.
No safety signal for this outcome.
Fatigue and thinking
Not enough evidenceA 2024 review of 11 trials in healthy people (346 people) found only two studies on fatigue, with a positive trend. Thinking accuracy was marginal and reaction time did not change. The evidence is insufficient.
1 studiesOral astaxanthin supplements; amounts varied.
Studies, doses and limits
What the trials found
The 2024 meta-analysis (11 randomised trials, 346 healthy people) found that two studies on subjective fatigue showed a positive trend. Cognitive accuracy after 8 to 12 weeks was marginal (SMD 0.12, 95% CI -0.02 to 0.26) and reaction time did not change significantly (SMD -0.08, -0.26 to 0.10).
Results
No clear benefit for tiredness or thinking.
Effect sizes as reported
Cognitive accuracy SMD 0.12 (-0.02 to 0.26); reaction time SMD -0.08 (-0.26 to 0.10).
Why this rating
Insufficient: only two fatigue studies, and the thinking results were marginal or null.
Form and dose studied
Oral astaxanthin supplements; amounts varied.
Who was studied
Healthy adults.
Limits
Small trials in healthy people only; nothing tested in older people with memory problems.
Why researchers looked
Astaxanthin is sold for tiredness and focus, so trials looked at fatigue and thinking tests.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Not established
The review describes astaxanthin as an antioxidant. No mechanism for effects on fatigue or thinking was tested in these trials.
A proposed mechanism does not show that the effect happens in people.
No safety signal for this outcome.
Digital eye strain in children
Very low certaintyOne 84-day trial in 64 children aged 10 to 14 found eye-strain questionnaire scores improved more with astaxanthin than with placebo. Tear production and visual acuity did not differ between groups. The authors work for the product maker.
1 studiesA branded astaxanthin capsule; amount is in the studies table only.
Studies, doses and limits
What the trials found
In a randomised, double-blind, placebo-controlled trial (NCT05602402), 64 children aged 10 to 14 with at least 4 hours of daily screen time and mild to moderate eye-strain symptoms took a 4 mg astaxanthin capsule daily or placebo for 84 days. The questionnaire score fell by 4.00 points with astaxanthin and 1.72 with placebo (a 20% between-group difference). Visual fatigue scores were 11.55 versus 15.78. Stereopsis and pupil light reflex improved. There was no difference between groups in tear production (Schirmer test), visual acuity, near point of accommodation, immune markers or safety measures.
Results
A possible small benefit for self-reported eye strain in one company-linked trial. No evidence for eye disease.
Effect sizes as reported
Questionnaire change -4.00 vs -1.72; visual fatigue 11.55 vs 15.78.
Why this rating
Very low: one trial of 64 children, self-reported questionnaires, authors employed by the product maker.
Form and dose studied
A branded astaxanthin capsule; amount is in the studies table only.
Who was studied
Children aged 10 to 14 with screen-related eye strain.
Limits
Single trial; industry-linked; mostly subjective measures. No source read shows benefit for macular degeneration, dry eye disease or other eye conditions.
Why researchers looked
Children spend long hours on screens, so one company-run trial tested eye strain.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Not established
The trial paper does not show how astaxanthin might act on the eyes, and no mechanism was read.
A proposed mechanism does not show that the effect happens in people.
Safety variables did not differ between groups in this trial. Ask a doctor before giving supplements to children.
Cholesterol and blood pressure
Low certaintyA 2022 review of 7 trials (321 adults at risk of metabolic syndrome) found a significant lowering of LDL cholesterol and marginal effects on total cholesterol and systolic blood pressure. The abstract gives no numbers, so the size of the effect is unknown.
1 studiesOral astaxanthin supplements; amounts varied.
Studies, doses and limits
What the trials found
The 2022 systematic review and meta-analysis (Nutrients) included 7 randomised trials with 321 adults at risk of metabolic syndrome. The authors report a significant attenuating effect on LDL cholesterol and marginal effects on total cholesterol and systolic blood pressure, and say more robust evidence is needed. The abstract gives no numbers.
Results
A small cholesterol effect may exist but is not measured in numbers the abstract shares, so it cannot be judged.
Effect sizes as reported
No numbers in the abstract.
Why this rating
Low: seven small trials and no effect sizes in the abstract. Methodological quality was rated good or excellent by the reviewers.
Form and dose studied
Oral astaxanthin supplements; amounts varied.
Who was studied
Adults with risk factors for metabolic syndrome.
Limits
Small trials; no heart-attack or stroke outcomes.
Why researchers looked
Because oxidative damage is linked to heart and metabolic risk, trials looked at cholesterol and blood pressure.
Traditional use
Astaxanthin is a supplement ingredient and a red-pink pigment. Selling it for general antioxidant or anti-ageing use is modern; nothing here shows a long traditional use.
Proposed mechanism Not established
No mechanism for a cholesterol effect was read in the abstract.
A proposed mechanism does not show that the effect happens in people.
See the Safety tab for what is known about medicines and bleeding.
Connections to the rest of health
How Astaxanthin connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Cellular Protection | Mixed findings | Oxidative stress blood markers: A 2022 review of 12 trials (380 people) found lower blood malondialdehyde, a marker of oxidative damage, with astaxanthin than with placebo. A 2026 review of 24 exercise trials found no significant change in malondialdehyde. A lower marker is not proof of better health. | 11 10 | |
| Healthy Skin | Low certainty | Skin moisture and elasticity: A 2021 meta-analysis of randomised trials found oral astaxanthin improved skin moisture and elasticity more than placebo. Wrinkle depth did not change significantly. Most studies were small, in healthy Japanese women, and many were funded by companies. | 14 13 | |
| Healthy Skin | Very low certainty | Skin response to UV light: In one 10-week trial of 23 healthy people, the astaxanthin group needed more UV light to redden their skin than the placebo group. The trial was small and sponsored by the product maker. It does not replace sunscreen or shade. | 7 13 | |
| Inflammation Balance | Not enough evidence | Inflammation blood markers: A 2022 meta-analysis found interleukin-6 was lower with astaxanthin in people with type 2 diabetes. CRP and TNF-alpha did not change significantly. A 2026 review of exercise trials found no significant change in IL-6. Evidence of a real health effect is insufficient. | 11 10 12 | |
| Muscle Recovery | Low certainty | Exercise recovery blood markers: A 2026 review of 24 trials in healthy people and athletes found lower creatine kinase (a muscle-damage marker) and lower lactate dehydrogenase with astaxanthin. The lactate dehydrogenase result varied a lot between trials. Lower markers did not come with better performance. | 10 | |
| Endurance Support | Mixed findings | Exercise performance: Reviews disagree. A 2026 review of 24 trials found no significant gain in VO2max, time-trial performance or maximal power. A 2024 review of 11 trials found better physical performance when astaxanthin was combined with regular training. Evidence is mixed and not established. | 10 9 | |
| Reduce Fatigue | Not enough evidence | Fatigue and thinking: A 2024 review of 11 trials in healthy people (346 people) found only two studies on fatigue, with a positive trend. Thinking accuracy was marginal and reaction time did not change. The evidence is insufficient. | 9 | |
| Mental Clarity | Not enough evidence | Fatigue and thinking: A 2024 review of 11 trials in healthy people (346 people) found only two studies on fatigue, with a positive trend. Thinking accuracy was marginal and reaction time did not change. The evidence is insufficient. | 9 | |
| Eye Comfort | Very low certainty | Digital eye strain in children: One 84-day trial in 64 children aged 10 to 14 found eye-strain questionnaire scores improved more with astaxanthin than with placebo. Tear production and visual acuity did not differ between groups. The authors work for the product maker. | 6 | |
| Cholesterol Balance | Low certainty | Cholesterol and blood pressure: A 2022 review of 7 trials (321 adults at risk of metabolic syndrome) found a significant lowering of LDL cholesterol and marginal effects on total cholesterol and systolic blood pressure. The abstract gives no numbers, so the size of the effect is unknown. | 8 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Whole Body | Biological association | Mixed findings | Studied for: Oxidative stress blood markers Studied for: Inflammation blood markers | 11 10 12 |
| Skin Hair Beauty | Biological association | Low certainty | Studied for: Skin moisture and elasticity Studied for: Skin response to UV light | 14 13 7 |
| Integumentary System | Biological association | Low certainty | Studied for: Skin moisture and elasticity | 14 13 |
| Immune System | Biological association | Not enough evidence | Studied for: Inflammation blood markers | 11 10 12 |
| Musculoskeletal System | Biological association | Low certainty | Studied for: Exercise recovery blood markers Studied for: Exercise performance | 10 9 |
| Energy Fatigue | Biological association | Mixed findings | Studied for: Exercise performance Studied for: Fatigue and thinking | 10 9 |
| Brain Focus | Biological association | Not enough evidence | Studied for: Fatigue and thinking | 9 |
| Eyes | Biological association | Very low certainty | Studied for: Digital eye strain in children | 6 |
| Cardiovascular System | Biological association | Low certainty | Studied for: Cholesterol and blood pressure | 8 |
C. Body parts and organs
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Malondialdehyde (MDA) | Biological association | Mixed findings | Measured in trials: lower. A lab change is not the same as a health benefit. | 11 10 |
| Interleukin-6 (IL-6) | Biological association | Not enough evidence | Measured in trials: lower. A lab change is not the same as a health benefit. | 11 10 |
| C-reactive protein (CRP) and TNF-alpha | Biological association | Low certainty | Measured in trials: lower. A lab change is not the same as a health benefit. | 11 |
| Creatine kinase (CK) | Biological association | Low certainty | Measured in trials: lower. A lab change is not the same as a health benefit. | 10 |
| Lactate dehydrogenase (LDH) | Biological association | Very low certainty | Measured in trials: lower. A lab change is not the same as a health benefit. | 10 |
| LDL cholesterol | Biological association | Low certainty | Measured in trials: lower. A lab change is not the same as a health benefit. | 8 |
K. Biological pathways
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Krill oil | Preliminary mechanism | Human | Contains astaxanthin; sold as an omega-3 product. | |
| Carotenoids (lutein, zeaxanthin, lycopene) | Preliminary mechanism | Human | Same chemical family (carotenoid pigments). | 14 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Astaxanthin | Biological association | Human | The studied active ingredient. Natural astaxanthin from Haematococcus pluvialis is used in most human studies read. | 14 5 4 |
| Synthetic astaxanthin | Biological association | Animal | Chemically different from the natural form, per the 2019 safety review. Few safety studies in people. | 2 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).
Evidence at a glance: what the research found for 9 outcomes
Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.
The evidence
The research centre for Astaxanthin. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing astaxanthin summary, re-read PubMed abstracts for reviews and trials, read two EFSA Journal abstracts through Europe PMC, and confirmed the chemical record in PubChem. Only abstracts were read for studies. US agency pages were not checked.
Study library: every study we checked 14
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Arefpour 2024 The effects of astaxanthin supplementation on liver enzyme levels. Int J Vitam Nutr Res · PMID 38407143 · DOI |
Systematic review meta analysis |
196 5 randomised trials in adults |
Oral astaxanthin supplements 6 to 12 mg a day in the trials 4 to 48 weeks · vs Placebo |
ALT was slightly higher with astaxanthin than placebo. AST, GGT and ALP did not change significantly. The authors call for longer, better trials. ALT +1.92 U/L (95% CI 0.16 to 3.68 U/L) Methods, limits and fundingOutcomes: ALT, AST, GGT and ALP liver enzymes Limitations: Only five trials; a small enzyme shift is not the same as liver injury, and the abstract does not report any liver injury. Funding and conflicts: Funding and conflicts are not stated in the abstract. Read: abstract |
| Brendler 2019 Astaxanthin: How much is too much? A safety review. Phytother Res · PMID 31788888 · DOI |
Narrative safety review |
Review of approved intake levels, 87 human studies of natural astaxanthin, and toxicology studies | Natural and synthetic astaxanthin Natural form from algae; synthetic form made chemically Approved or recommended amounts differed between countries (2 to 24 mg a day, per the abstract) Varied |
None of 87 human studies of natural astaxanthin found safety concerns, 35 of them at 12 mg a day or more. The 2 mg a day ADI proposed by EFSA came from a rat study of synthetic astaxanthin. The authors say synthetic and natural astaxanthin are chemically different and should be assessed separately. 87 human studies, none with safety concerns (Not applicable) Methods, limits and fundingOutcomes: Safety findings in human and animal studies; acceptable daily intake (ADI) Limitations: A review of published studies, not a new trial. Few safety studies of synthetic astaxanthin exist. One author works for an herbal products company; funding is not stated in the abstract. Funding and conflicts: Funding is not stated in the abstract. One author is affiliated with Traditional Medicinals. Read: abstract |
| Dobre 2025 Navigating the Effects of Anti-Atherosclerotic Supplements and Acknowledging Associated Bleeding Risks. Int J Mol Sci · PMID 41155474 · DOI |
Narrative review |
Review of heart and blood-vessel supplements | Many supplements; astaxanthin is named once among antioxidants |
The abstract names astaxanthin among antioxidant agents (with vitamin C, vitamin E, resveratrol and coenzyme Q) that provide vascular protection but can interfere with hemostasis (blood clotting), metabolism or redox-sensitive pathways. It gives no astaxanthin-specific data. No numbers (Not applicable) Methods, limits and fundingOutcomes: Benefits and bleeding or interaction risks of heart-related supplements Limitations: Astaxanthin is a passing mention in the abstract. No clotting results for astaxanthin are given there. Funding and conflicts: The authors declare no conflicts of interest. Read: abstract |
| EFSA Panel on Nutrition 2025 Safety of the extension of use of oleoresin from Haematococcus pluvialis containing astaxanthin as a novel food pursuant to Regulation (EU) 2015/2283. EFSA J · PMID 41346946 · DOI |
Regulatory opinion n/a |
Not applicable (regulatory safety opinion) | Haematococcus pluvialis astaxanthin novel food Oleoresin (about 10% astaxanthin) |
The panel set the acceptable daily intake (ADI) for astaxanthin at 0.2 mg per kg body weight per day. Adding astaxanthin from food supplements, children aged 3 and over and adolescents would be above it, and adults at it. The panel judged the new uses safe provided astaxanthin food supplements are not eaten the same day by children and adolescents. ADI 0.2 mg per kg body weight per day (Not applicable) Methods, limits and fundingOutcomes: Safety of use as a novel food; combined intake against the acceptable daily intake (ADI) Limitations: Abstract read through Europe PMC. This is a regulator opinion about added uses in dairy-style drinks and juices, not a health trial. Funding and conflicts: Regulator opinion; applicant intake assessments underlie it. Read: abstract |
| EFSA Panel on Nutrition 2025 Safety of algal meal from Haematococcus pluvialis containing astaxanthin as a novel food pursuant to Regulation (EU) 2015/2283. EFSA J · PMID 41346945 · DOI |
Regulatory opinion n/a |
Not applicable (regulatory safety opinion) | Haematococcus pluvialis astaxanthin novel food Algal meal (about 5% astaxanthin) |
The panel set the acceptable daily intake (ADI) for astaxanthin at 0.2 mg per kg body weight per day. Adding astaxanthin from food supplements, children aged 3 and over and adolescents would be above it, and adults at it. The panel judged the new uses safe provided astaxanthin food supplements are not eaten the same day by children and adolescents. ADI 0.2 mg per kg body weight per day (Not applicable) Methods, limits and fundingOutcomes: Safety of use as a novel food; combined intake against the acceptable daily intake (ADI) Limitations: Abstract read through Europe PMC. This is a regulator opinion about added uses in dairy-style drinks and juices, not a health trial. Funding and conflicts: Regulator opinion; applicant intake assessments underlie it. Read: abstract |
| Hecht 2025 Astaxanthin (AstaReal(R)) Improved Acute and Chronic Digital Eye Strain in Children: A Randomized Double-Blind Placebo-Controlled Trial. Adv Ther · PMID 40014233 · DOI |
Randomised controlled trial |
64 64 children aged 10 to 14 with at least 4 hours of daily screen time and mild to moderate digital eye strain symptoms |
Branded astaxanthin soft capsule (AstaReal) Source not stated in the abstract 4 mg a day in the trial 84 days · vs Placebo |
Questionnaire scores fell more with astaxanthin than placebo (a 20% between-group difference). Visual fatigue scores were lower. Tear production, visual acuity, immune markers and safety measures did not differ between groups. CVS-Q change -4.00 vs -1.72 points; visual fatigue 11.55 vs 15.78 (Not given in the abstract) Methods, limits and fundingOutcomes: Computer Vision Syndrome Questionnaire score (primary), visual fatigue scale, eye tests and safety measures Limitations: Single trial. Eye-strain scores are self-reported questionnaires. Authors are employed by the product maker or its subsidiaries. Funding and conflicts: Several authors are employees of the product maker (Fuji Chemical Industries) and its subsidiaries; a contract research organisation hired by Fuji ran the study. Registered as NCT05602402. Registration: NCT05602402; CTRI/2022/10/046606 Read: abstract |
| Ito 2018 The Protective Role of Astaxanthin for UV-Induced Skin Deterioration in Healthy People-A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients · PMID 29941810 · DOI |
Randomised controlled trial |
23 23 healthy Japanese adults |
Astaxanthin capsule Source not stated in the abstract 4 mg a day in the trial 10 weeks (UV tests after 9 weeks) · vs Placebo capsule |
The astaxanthin group needed more UV to redden the skin than placebo, lost less skin moisture in the irradiated area, and rated rough skin and texture better in non-irradiated areas. Numbers not given in the abstract (Not applicable) Methods, limits and fundingOutcomes: Minimal erythema dose (UV dose needed to redden skin), skin moisture, transepidermal water loss, self-rated skin condition Limitations: Very small trial. Sponsor and funder was the maker of the product (the authors work for it). It does not replace sunscreen. Funding and conflicts: The authors work for FUJIFILM Corporation, a sponsor and funder of the study. Read: abstract |
| Leung 2022 Astaxanthin Influence on Health Outcomes of Adults at Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis. Nutrients · PMID 35631193 · DOI |
Systematic review meta analysis |
321 7 randomised trials in adults with risk factors for metabolic syndrome |
Oral astaxanthin supplements Varied Varied · vs Placebo |
The review found marginal effects on total cholesterol and systolic blood pressure, and a significant lowering of LDL cholesterol. The authors say more robust evidence is needed. No numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Cholesterol, LDL cholesterol, blood pressure and other metabolic syndrome measures Limitations: Seven small trials; numbers were not given in the abstract. Funding and conflicts: The authors declare no conflict of interest. Funding is not stated in the abstract. Read: abstract |
| Liu 2024 Effects of Astaxanthin Supplementation on Fatigue, Motor Function and Cognition: A Meta-Analysis of Randomized Controlled Trials. Biol Res Nurs · PMID 38243785 · DOI |
Systematic review meta analysis |
346 11 randomised trials in healthy people |
Oral astaxanthin supplements Varied 8 to 12 weeks for cognition results; longer in some subgroups · vs Placebo |
Only two studies measured fatigue (a positive trend). Cognitive accuracy was marginal and reaction time was not significant. With regular training, fat oxidation and physical performance were higher, especially for aerobic exercise. Cognitive accuracy SMD 0.12; reaction time SMD -0.08; physical performance SMD 0.62; fat oxidation SMD 2.56 (95% CI -0.02 to 0.26; -0.26 to 0.10; 0.17 to 1.06; 1.24 to 3.89) Methods, limits and fundingOutcomes: Subjective fatigue, cognitive accuracy, reaction time, fat oxidation, physical performance with training Limitations: Small trials in healthy people; the performance finding conflicts with the larger 2026 review of 24 trials, which found no gain in VO2max, time-trial or power. Funding and conflicts: The authors declared no potential conflicts of interest. Funding is not stated in the abstract. Read: abstract |
| Liu 2026 The Effects of Astaxanthin Supplementation on Exercise Recovery Biomarkers and Exercise Performance: A Systematic Review and Meta-Analysis. Nutrients · PMID 42197030 · DOI |
Systematic review meta analysis |
24 randomised trials in healthy people and athletes | Oral astaxanthin supplements Varied; the authors call for standardised dosing Varied · vs Placebo or control |
Creatine kinase (a muscle-damage marker) and lactate dehydrogenase were lower with astaxanthin. Malondialdehyde and IL-6 did not change significantly. VO2max, time-trial performance and maximal power did not improve significantly. Creatine kinase SMD -0.45; lactate dehydrogenase SMD -0.93 (95% CI -0.83 to -0.07 (creatine kinase); -1.39 to -0.48 (lactate dehydrogenase)) Methods, limits and fundingOutcomes: Creatine kinase, lactate dehydrogenase, malondialdehyde, IL-6; VO2max, time-trial performance, maximal power Limitations: Large differences between trials for lactate dehydrogenase; the authors say to read it cautiously. Exercise plans and outcomes varied. Funding and conflicts: The authors declare that they have no competing interests. Funding is not stated in the abstract. Read: abstract |
| Ma 2022 Astaxanthin supplementation mildly reduced oxidative stress and inflammation biomarkers: a systematic review and meta-analysis of randomized controlled trials. Nutr Res · PMID 35091276 · DOI |
Systematic review meta analysis |
380 12 randomised trials; adults including people with type 2 diabetes and overweight people |
Astaxanthin supplements (forms and amounts varied) Varied; at least 1 week of use 1 week or longer · vs Placebo |
Blood malondialdehyde was lower with astaxanthin than placebo. The drop was seen in type 2 diabetes too. Interleukin-6 fell in type 2 diabetes. CRP and TNF-alpha did not change significantly. Malondialdehyde SMD -0.95; IL-6 in type 2 diabetes -0.70 pg/mL (95% CI -1.67 to -0.23 (malondialdehyde); -1.29 to -0.11 pg/mL (IL-6)) Methods, limits and fundingOutcomes: Blood markers of oxidative stress (malondialdehyde, superoxide dismutase, isoprostane) and inflammation (IL-6, CRP, TNF-alpha) Limitations: Few trials per marker. The review authors call the effect mild. Markers are not health outcomes. Funding and conflicts: The authors declare no conflicts of interest. Funding is not stated in the abstract. Read: abstract |
| Malcangi 2026 The Role of Astaxanthin as an Antioxidant and Anti-Inflammatory Agent in Human Health: A Systematic Review. Int J Mol Sci · PMID 41596351 · DOI |
Systematic review |
Human studies of mixed designs and conditions (no pooled analysis in the abstract) | Oral astaxanthin supplements Varied Varied · vs Varied |
The review reports that astaxanthin lowered inflammatory markers (IL-6, TNF-alpha, TGF-beta1) and raised antioxidant capacity in the studies it gathered. It also reports gains in combination with exercise and in small studies of women with PCOS. It says well-designed trials are needed. No pooled numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Oxidative stress markers, inflammatory cytokines, metabolic and other measures Limitations: Pools studies of very different designs and groups. The 2022 and 2026 meta-analyses found more modest results, so this review is treated as low-weight. Funding and conflicts: The authors declare no conflicts of interest. Read: abstract |
| Ng 2021 Effects of Astaxanthin Supplementation on Skin Health: A Systematic Review of Clinical Studies. J Diet Suppl · PMID 32202443 · DOI |
Systematic review |
11 clinical studies (6 randomised, double-blind trials; the rest open-label); mostly healthy Japanese women | Oral astaxanthin supplements Reviewers describe the studied range as 3 to 6 mg a day Varied · vs Placebo (randomised trials) |
In many of the randomised trials, skin texture, appearance and moisture improved. Astaxanthin also appeared to protect against UV skin damage. No serious adverse events were reported. No pooled numbers in the abstract (Not applicable) Methods, limits and fundingOutcomes: Skin texture, wrinkles, moisture, UV-induced skin damage, adverse events Limitations: Most studies were small and in healthy Japanese women. The reviewers say many studies were funded by commercial companies and that this could not be accounted for. Funding and conflicts: Commercial funding of many included studies, as noted by the reviewers. Read: abstract |
| Zhou 2021 Systematic Review and Meta-Analysis on the Effects of Astaxanthin on Human Skin Ageing. Nutrients · PMID 34578794 · DOI |
Systematic review meta analysis |
9 randomised oral-astaxanthin trials plus 2 open-label studies (topical or oral plus topical) | Oral astaxanthin from Haematococcus pluvialis microalgae (per the abstract) Microalgae extract Varied Varied · vs Placebo |
Oral astaxanthin improved skin moisture and elasticity compared with placebo. Wrinkle depth did not change significantly. Moisture SMD 0.53; elasticity SMD 0.77; wrinkle depth SMD -0.26 (not significant) (95% CI 0.05 to 1.01 (moisture); 0.19 to 1.35 (elasticity); -0.58 to 0.06 (wrinkles)) Methods, limits and fundingOutcomes: Skin moisture, elasticity and wrinkle depth Limitations: Small studies; moderate to high differences between trials (I2 52% and 75%). The authors conclude it may reduce wrinkles, but the wrinkle result was not significant. Funding and conflicts: The authors declare no conflict of interest. Funding is not stated in the abstract. Read: abstract |
What we do not know yet
- History of use as a supplement was not read from a source, so none is stated.
- Absorption and how the body handles astaxanthin were not read.
- Food amounts per portion were not found.
- Which source (algae, yeast, krill, synthetic) was used in each trial is not always stated in the abstracts.
- No large, independent trial was read that tests astaxanthin on a health outcome rather than a blood marker.
- Skin trials were mostly in healthy Japanese women and many were funded by companies.
- No trial was read that tests astaxanthin for eye disease such as macular degeneration or dry eye disease.
- No safety data for pregnancy or breastfeeding were found in the sources read.
- The US FDA, NIH Office of Dietary Supplements, NCCIH and LiverTox were not checked for astaxanthin.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Metabolic 1
LDL cholesterol
Lower in trials
Often called "bad" cholesterol; higher levels are linked to heart disease risk.
Low certaintyResults and what it means
Why it was measured
To see whether astaxanthin changes blood fats in adults at risk of metabolic syndrome.
Statistical vs. clinical meaning
A lab marker with no effect size in the abstract; not proof of fewer heart problems.
Safety implication
Ask a doctor before adding supplements to cholesterol medicines.
| Study | Result | People | Product |
|---|---|---|---|
| 8 | A significant lowering effect reported; no numbers in the abstract | 7 trials, 321 adults at risk of metabolic syndrome | Oral astaxanthin, forms and amounts varied |
Other 5
Malondialdehyde (MDA)
Lower in trials
A blood marker of damage to fats by oxidation. Higher levels suggest more oxidative stress.
Mixed findingsResults and what it means
Why it was measured
To see whether astaxanthin lowers a marker of oxidative damage.
Statistical vs. clinical meaning
A lab marker that moved in one review and not in another; not proof of better health.
Safety implication
None found for this marker.
Interleukin-6 (IL-6)
Lower in trials
A blood signal produced during inflammation.
Not enough evidenceResults and what it means
Why it was measured
To see whether astaxanthin lowers a marker of inflammation.
Statistical vs. clinical meaning
Changed in one group only; no health effect shown.
Safety implication
None found for this marker.
| Study | Result | People | Product |
|---|---|---|---|
| 11 | Lower in people with type 2 diabetes (-0.70 pg/mL, 95% CI -1.29 to -0.11) | Adults with type 2 diabetes in the pooled trials | Oral astaxanthin, forms and amounts varied |
| 10 | No significant effect in exercise trials | 24 trials in healthy people and athletes | Oral astaxanthin, forms and amounts varied |
C-reactive protein (CRP) and TNF-alpha
Lower in trials
Two more blood markers of inflammation.
Low certaintyResults and what it means
Why it was measured
To see whether astaxanthin changes general inflammation markers.
Statistical vs. clinical meaning
A null result: astaxanthin did not move these markers in the pooled trials.
Safety implication
None found.
| Study | Result | People | Product |
|---|---|---|---|
| 11 | No significant change in either marker | Pooled trials | Oral astaxanthin, forms and amounts varied |
Creatine kinase (CK)
Lower in trials
An enzyme that leaks from damaged muscle into the blood after hard exercise.
Low certaintyResults and what it means
Why it was measured
To see whether astaxanthin lowers a muscle-damage marker after exercise.
Statistical vs. clinical meaning
The most consistent finding in the 2026 review, but it did not come with better performance.
Safety implication
None found.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | Lower with astaxanthin (SMD -0.45, 95% CI -0.83 to -0.07) | 24 trials in healthy people and athletes | Oral astaxanthin, forms and amounts varied |
Lactate dehydrogenase (LDH)
Lower in trials
An enzyme released from damaged cells, including muscle.
Very low certaintyResults and what it means
Why it was measured
A second muscle-damage marker measured in exercise trials.
Statistical vs. clinical meaning
The authors say to read this result cautiously.
Safety implication
None found.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | Lower with astaxanthin (SMD -0.93, 95% CI -1.39 to -0.48), with substantial differences between trials | 24 trials in healthy people and athletes | Oral astaxanthin, forms and amounts varied |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 3
- Safety record is reassuring but limited. A 2019 safety review found none of 87 human studies of natural astaxanthin reported safety concerns, 35 of them at 12 mg a day or more. Most trials last weeks to months, so long-term safety is not known. Natural (algae-based) and synthetic astaxanthin are chemically different, and synthetic astaxanthin has been studied much less in people. Review of clinical and toxicology studies 2
- Liver enzyme ALT rose slightly in trials. A 2024 meta-analysis of 5 trials (196 adults) found ALT, a liver enzyme, was slightly higher with astaxanthin than placebo (1.92 U/L higher). AST, GGT and ALP did not change significantly. No liver injury was reported in the abstract. Ask a doctor if you have liver disease or take medicines that affect the liver. Meta-analysis 1
- Limited data for children, pregnancy and breastfeeding. One 84-day trial in 64 children aged 10 to 14 found no difference in safety measures versus placebo, but the trial was run by the product maker. No source read gives safety data for pregnancy or breastfeeding. EFSA says astaxanthin food supplements should not be eaten on the same day as certain added-astaxanthin foods by children and adolescents, because combined intake can pass its acceptable daily intake. Trial and regulator opinion 6 4 5
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Slightly higher ALT liver enzyme The review used amounts of 6 to 12 mg a day for 4 to 48 weeks. The authors call for longer trials. | Mean difference 1.92 U/L (95% CI 0.16 to 3.68) in 5 trials of 196 adults | A small laboratory change; no injury was described in the abstract Not reported in the abstract. | Meta-analysis 1 |
| Serious adverse events Studies were small and short. | None reported in the skin trials reviewed in 2021 | Not applicable Not applicable | Systematic review 13 |
| No difference in safety measures versus placebo in children Abstract does not list side effects individually. | 64 children, 84 days | Not applicable Not applicable | Randomised trial (industry linked) 6 |
Liver
A 2024 meta-analysis found a small rise in ALT with astaxanthin and no change in AST, GGT or ALP. No case of liver injury from astaxanthin was found in the sources read. The liver-safety reference LiverTox was not checked. 1
How often. No frequency of liver injury was found.
Monitoring. No agency monitoring advice was found.
This is a safety connection. It is not evidence that Astaxanthin supports liver health.
Medicines and supplements 3
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Blood thinners and anti-clotting medicines prescription | A 2025 review lists astaxanthin among antioxidant supplements that can interfere with hemostasis (blood clotting), metabolism or redox-sensitive pathways. | The abstract gives no astaxanthin-specific bleeding data. This is a possible interaction, not a documented one. | Review mention Very low certainty 3 | Ask a doctor or pharmacist before combining astaxanthin with blood thinners. |
| Blood pressure and cholesterol medicines prescription | A meta-analysis found marginal lowering of systolic blood pressure and a significant lowering of LDL cholesterol with astaxanthin alone. | No interaction study was read. Whether adding astaxanthin to these medicines changes their effect is unknown. | Inference from trial effects Not enough evidence 8 | Ask a doctor or pharmacist before combining. |
| Other antioxidant supplements (vitamin C, vitamin E, coenzyme Q10) supplement | The same 2025 review groups astaxanthin with these as antioxidants that can interfere with clotting or other pathways. | No data on combinations were given in the abstract. | Review mention Very low certainty 3 | Ask a pharmacist when combining several antioxidant supplements. |
Who should check first 4
| Situation | Advice | Evidence |
|---|---|---|
| Pregnancy and breastfeeding | No safety data were found in the sources read. Ask a doctor before using astaxanthin. | Absence of data |
| Children and adolescents | Only one trial in 64 children aged 10 to 14 was read. EFSA says astaxanthin food supplements should not be eaten on the same day as foods with added astaxanthin by children and adolescents. Ask a doctor first. | Trial and regulator opinion 6 5 4 |
| Liver disease or liver-enzyme medicines | A small ALT rise was seen in trials. Ask a doctor first. | Meta-analysis 1 |
| Planned surgery or bleeding disorders, or taking blood thinners | Astaxanthin is named among antioxidants that may affect clotting. Evidence is weak. Tell your doctor or pharmacist. | Review mention 3 |
Overdose, product quality and regulators
Summary. Natural astaxanthin has a good safety record in human studies, and no toxicity signal was seen in the 87 human studies reviewed. The acceptable daily intake EFSA proposed in 2019 was based on an animal study of the synthetic form.
Animal. A rat toxicology study of synthetic astaxanthin was the basis for the acceptable daily intake EFSA proposed in 2019 (as reported by the safety review).
High dose or long term signals. Long-term safety beyond weeks to months was not found in the sources read. A small ALT rise was seen in trials up to 48 weeks.
Overdose response. Not found in the sources read.
Genotoxicity. Not researched.
Contamination and label accuracy of astaxanthin supplements were not researched. The only quality point found is the difference between natural and synthetic forms.
Natural versus synthetic astaxanthin. The 2019 safety review says synthetic astaxanthin is chemically different from natural astaxanthin from algae, and that human safety trials of the synthetic form are few. Products do not always say which form they contain; this was not checked. 2
| Body | Action | Date |
|---|---|---|
| European Food Safety Authority (EFSA), NDA Panel (European Union) | Sets an acceptable daily intake (ADI) for astaxanthin of 0.2 mg per kg body weight per day. Says that combined intake from food, added-astaxanthin foods and food supplements would exceed the ADI for children aged 3 and over and for adolescents, and be at the ADI for adults. Judges two new uses (dairy analogues, beverage whiteners, fruit juices) safe provided astaxanthin food supplements are not eaten the same day by children and adolescents. This is a regulator statement, not advice to take astaxanthin. source | 2025-12 |
| Approved intake levels by country (as reported in a 2019 review) (Various) | A 2019 review says recommended or approved amounts for astaxanthin differ between countries, and describes an acceptable daily intake of 2 mg a day recently proposed by EFSA (as of 2019), based on a rat study of synthetic astaxanthin. The review authors argue for separate limits for natural and synthetic forms. source | 2019-12 |
When to get medical help
- Signs of an allergic reaction such as hives, swelling of the face or throat, or trouble breathing: stop and get emergency help.
- Yellow skin or eyes, dark urine, or pain in the upper right belly: contact a doctor. These are general signs of a liver problem, not signs specific to astaxanthin.
- Unusual bleeding or bruising while taking blood thinners: contact a doctor or pharmacist.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What is astaxanthin?
Is astaxanthin the same as krill oil?
No. Krill oil is an omega-3 oil that contains astaxanthin. Astaxanthin supplements are sold on their own and are often made from algae.
Does astaxanthin help skin?
Does astaxanthin protect against sunburn?
One 23-person trial sponsored by the product maker found skin needed more UV to redden. It does not replace sunscreen or shade.
Does astaxanthin help exercise performance or recovery?
Does astaxanthin help with tiredness or memory?
The evidence is insufficient. A 2024 review found only two fatigue studies and marginal or no effect on thinking tests in healthy people.
Does astaxanthin help tired eyes from screens?
One company-linked 84-day trial in 64 children found less self-reported eye strain than placebo, but tear production and visual acuity did not differ. No evidence was read for eye disease.
Does astaxanthin lower cholesterol or blood pressure?
A 2022 review of 7 trials reports a significant LDL cholesterol lowering and marginal effects on total cholesterol and systolic blood pressure. The abstract gives no numbers, so the evidence is low-certainty.
Is astaxanthin safe?
Does astaxanthin interact with medicines?
No proven interaction was read. A 2025 review groups astaxanthin with antioxidants that may affect clotting, so ask a pharmacist if you take blood thinners.
Is astaxanthin safe in pregnancy or for children?
No safety data for pregnancy or breastfeeding were found. For children, one company-linked trial in 10 to 14 year olds showed no difference in safety measures, and EFSA advises against children and adolescents eating astaxanthin supplements on the same day as certain added-astaxanthin foods. Ask a doctor first.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-26
- Last substantive update
- 2026-10-26
- How we research
- We started from our existing astaxanthin summary, re-read PubMed abstracts for reviews and trials, read two EFSA Journal abstracts through Europe PMC, and confirmed the chemical record in PubChem. Only abstracts were read for studies. US agency pages were not checked.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. Several trials were funded by or linked to companies that make astaxanthin, as noted in the studies table.
Sources 14
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Arefpour H, Rasaei N, Amini MR, Salavatizadeh M, Hashemi M, Makhtoomi M, Hajiaqaei M, Gholizadeh M, Askarpour M, Hekmatdoost A. The effects of astaxanthin supplementation on liver enzyme levels.. Int J Vitam Nutr Res. 2024. PMID 38407143. DOI 10.1024/0300-9831/a000804. (abstract)
- Brendler T, Williamson EM. Astaxanthin: How much is too much? A safety review.. Phytother Res. 2019. PMID 31788888. DOI 10.1002/ptr.6514. (abstract)
- Dobre MZ, Virgolici B, Doicin IC, Virgolici H, Stanescu-Spinu II. Navigating the Effects of Anti-Atherosclerotic Supplements and Acknowledging Associated Bleeding Risks.. Int J Mol Sci. 2025. PMID 41155474. DOI 10.3390/ijms262010183. (abstract)
- EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Safety of the extension of use of oleoresin from Haematococcus pluvialis containing astaxanthin as a novel food pursuant to Regulation (EU) 2015/2283.. EFSA J. 2025. PMID 41346946. DOI 10.2903/j.efsa.2025.9737. (abstract)
- EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Safety of algal meal from Haematococcus pluvialis containing astaxanthin as a novel food pursuant to Regulation (EU) 2015/2283.. EFSA J. 2025. PMID 41346945. DOI 10.2903/j.efsa.2025.9736. (abstract)
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Where to buy
Check the label first. Whatever you buy, look for these:
- The amount of the active ingredient per serving, not just the front-label claim
- A third-party testing mark (USP, NSF or ConsumerLab)
- Other ingredients and allergens
- Ask a pharmacist about interactions with your medicines
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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