Astaxanthin
Astaxanthin is the red carotenoid that makes salmon pink and cooked shrimp red. Microalgae make it, seafood passes it on, and supplements are the most concentrated source.
No set daily amount
8 mg a day from supplements, judged safe for adults by EFSA
Vitamin A · none; it is not turned into vitamin A
- Made by Microalgae and some yeasts
- Main sources Salmon and shellfish none in plant foods
- Human evidence Small trials mixed results, no clear benefit
- In Caltide Not totaled yet food tables do not list it
Safety: EFSA opinion on astaxanthin in food supplements (2020).
Astaxanthin Food Sources
Food tables do not measure astaxanthin, so these are the sources by kind, without amounts. An ordinary diet supplies little unless it includes salmon or shellfish often.
- Salmon and troutwild fish get it from krill and other prey; farmed fish from their feed
- Shrimp, crab, lobster, and crayfishthe same pigment colors their shells
- Krill and fish roekrill oil owes its red color to astaxanthin
- Plant foodsessentially none
- Supplementsthe most concentrated source, mostly made from algae extract
What Is Astaxanthin?
Astaxanthin is a xanthophyll, a carotenoid with oxygen in its rings, like lutein and zeaxanthin. In the green microalga Haematococcus pluvialis it builds up when the cells are stressed by strong light or lack of nutrients, turning them blood red.
How Astaxanthin Gets Into Salmon
Fish cannot make astaxanthin themselves. Krill and other small crustaceans take it in from algae, and fish such as salmon eat the crustaceans and store the pigment in their muscle. That is why salmon flesh is pink while most fish is white.
Farmed salmon eat pellets, not krill, so astaxanthin is added to their feed, either made synthetically or grown in algae or yeast. Without it, the fillet would be pale. EFSA assesses it as a feed additive for this use.
Why Shrimp Turns Red When Cooked
A raw shrimp or lobster looks gray, brown or blue because its astaxanthin is bound to proteins, in lobster one called crustacyanin, which shift the color it reflects. Heat unfolds the proteins and releases the pigment, and its own red-orange shows. The astaxanthin was there all along.
Astaxanthin Benefits: What Human Studies Show
In lab studies, astaxanthin is a strong antioxidant. Human research is much thinner: mostly small, short trials on skin, eye strain, exercise, and blood lipids, with mixed results. None has established a health benefit, and astaxanthin does not provide vitamin A.
Common Astaxanthin Mistakes
Reading the extract, not the astaxanthin. A label may give the weight of algae extract and, separately, the astaxanthin it provides. Only the second figure tells you the dose.
Counting on krill oil for it. Krill oil is red because of astaxanthin, but it is sold for its omega-3 fats, and not every label says how much astaxanthin it holds.
Expecting it to work like vitamin A. Unlike beta-carotene, astaxanthin is not turned into vitamin A in people, so it does not count toward vitamin A needs.
Astaxanthin Supplements
Supplements are also a source, and the main one for people who rarely eat salmon or shellfish. They come in two kinds, and both are best taken with a meal that has some fat.
Algal or Synthetic Astaxanthin
- From Haematococcus algaethe usual supplement form; mostly bound to fatty acids as esters, which the gut splits before absorbing
- Syntheticused mainly in fish feed; free rather than esterified, and a mix of mirror-image forms
Astaxanthin Safety
In 2020 EFSA concluded that 8 mg a day from supplements is safe for adults, on top of astaxanthin from food. Interactions with medicines have not been well studied, so ask a pharmacist if you take any.
Sources are listed at the end of this page. Not medical advice.
Astaxanthin in Caltide
- Not totaled yetFood tables do not list astaxanthin, so Caltide does not add it up from the foods or supplements you log. Salmon and shrimp you log still count for all their other nutrients.
Astaxanthin Sources and References
The figures and claims on this page are checked against these sources.
Questions About Astaxanthin
Astaxanthin is a red carotenoid made by microalgae such as Haematococcus pluvialis and by some yeasts. It passes up the food chain and gives salmon, trout, shrimp and krill their pink to red color.
Salmon, trout, shrimp, crab, lobster, crayfish, krill and fish roe. Plant foods have essentially none, so most people get little from diet unless they eat salmon or shellfish often.
Because of astaxanthin. In a raw shell it is bound to a protein that makes it look blue-gray or brown; heat unfolds the protein and frees the red-orange pigment.
Yes. Farmed salmon cannot get it from wild algae and krill, so astaxanthin is added to their feed; without it their flesh would be pale. EFSA has assessed it as a feed additive for salmon and trout.
In 2020 EFSA concluded that 8 mg a day from supplements is safe for adults, on top of what food provides. Interactions with medicines have not been well studied.
It is not established. Most human studies are small and short, with mixed results, and none has established a benefit for skin, eyes, exercise or heart health.
No. Astaxanthin is not a provitamin A carotenoid in people, so it adds nothing to your vitamin A intake.
Not yet. Food tables do not list it, so Caltide does not total astaxanthin from food or supplements.
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