Astaxanthin is a naturally occurring red-orange pigment in the carotenoid family. It is found in microalgae and enters various fish and crustaceans through aquatic food chains.
This article explains the origin and chemical properties of astaxanthin and distinguishes terms such as xanthophyll, algal biomass and oleoresin.
What is astaxanthin?
Astaxanthin belongs to the xanthophylls, a subgroup of carotenoids. It is related to other carotenoids but has its own molecular structure with oxygen-containing groups.
This structure influences its colour and solubility. Astaxanthin is fat-soluble and is not officially classified as a vitamin.
What role does Haematococcus pluvialis play?
Haematococcus pluvialis is a freshwater microalga. Under favourable growth conditions it appears mainly green. Under changed environmental conditions, such as high light intensity or limited nutrient availability, it can accumulate astaxanthin and develop a reddish colour.
Cultivated algal biomass can be harvested, dried and further processed. Astaxanthin-containing material may therefore occur in different raw-material forms.
Why are salmon and shrimp reddish?
Astaxanthin and related carotenoids pass through aquatic food chains. Small organisms take up the pigments and may then be consumed by larger animals.
The reddish colour of salmon, trout, shrimp and krill is partly associated with stored carotenoids. Colour alone, however, does not provide an exact measurement of astaxanthin content.
What do algal biomass and oleoresin mean?
- Algal biomass: harvested and dried material from cultivated microalgae.
- Algal meal: ground or otherwise processed algal biomass.
- Oleoresin: an oil-like extract containing astaxanthin and other fat-soluble constituents.
- Total astaxanthin: the analytically determined amount of astaxanthin in a material.
The name of a raw material and its actual astaxanthin content are not the same specification. Free and fatty-acid-bound, or esterified, forms may also be distinguished.
Natural and synthetic astaxanthin
Astaxanthin can be obtained from biological sources or produced synthetically. Depending on the source, the distribution of spatial molecular forms and the proportion of free and esterified forms may differ.
The word “natural” primarily describes origin. On its own, it is not evidence of a health effect, quality or suitability.
What does “antioxidant” mean in scientific research?
Astaxanthin can interact with reactive molecules in laboratory and model systems. Such observations are often described as antioxidant activity.
A laboratory reaction, absorption into the body, a change in a biomarker and a clinically relevant effect are separate levels of evidence. A finding in a test system does not automatically demonstrate a health effect in humans.
What has EFSA assessed?
The European Food Safety Authority has assessed astaxanthin-rich materials from Haematococcus pluvialis in the context of European novel food legislation.
These assessments concern defined materials, uses, population groups and exposure levels. A safety assessment or novel food authorisation is different from authorisation of a health claim.
Are there authorised health claims?
Health claims for foods are regulated separately in the European Union. The current general list of authorised health claims does not contain a specific claim for astaxanthin.
Laboratory findings and novel food assessments do not replace authorisation under health-claims legislation. This article therefore makes no statement about the effect of an astaxanthin-containing product.
Conclusion
Astaxanthin is a fat-soluble, red-orange xanthophyll carotenoid. A well-known natural source is the microalga Haematococcus pluvialis. Through food chains, the pigment can also occur in fish and crustaceans.
Algal biomass, oleoresin and actual astaxanthin content describe different characteristics. Laboratory findings, safety assessments and authorised health claims must also be distinguished.
Frequently asked questions
Is astaxanthin a vitamin?
No. Astaxanthin is a carotenoid, more specifically a xanthophyll.
Is astaxanthin the same as beta-carotene?
No. Both are carotenoids, but they differ in chemical structure and properties.
Does salmon contain astaxanthin?
Salmon can take up astaxanthin and related carotenoids through its diet and store them in its tissues.
Does a strong red colour prove a high astaxanthin content?
No. Accurate measurement requires an appropriate analytical method.
Does an EFSA safety assessment confirm a health effect?
No. A safety assessment examines defined conditions of use. Health claims are subject to a separate European authorisation procedure.
Scientific sources
- Ambati RR et al. Astaxanthin: Sources, Extraction, Stability, Biological Activities and Its Commercial Applications. Marine Drugs. 2014.
- Shah MMR et al. Astaxanthin-Producing Green Microalga Haematococcus pluvialis. 2016.
- EFSA NDA Panel. Safety of astaxanthin for its use as a novel food in food supplements. 2020.
- EFSA NDA Panel. Safety of the extension of use of astaxanthin-containing oleoresin. 2025.
Note: This article provides general scientific information, does not refer to a specific product and is not a substitute for medical advice, diagnosis or treatment.
