Astaxanthin: Benefits, Dose, UK Rules, Side Effects and Who Should Avoid It

What is astaxanthin?

Astaxanthin is a fat-soluble carotenoid, in the same pigment family as beta-carotene and lutein, but deep red. The microalga Haematococcus pluvialis makes large amounts of it when stressed by strong light, and animals that eat the algae, or the krill and shrimp that eat it, store the colour in their flesh and shells.

Astaxanthin is often called a “super antioxidant” in adverts. That phrase comes mostly from lab tests, not from proof of health effects in people, and there are no authorised health claims for astaxanthin in Great Britain.

How much astaxanthin should you take a day?

Most astaxanthin supplements give 4 to 12mg a day, and skin trials mostly used 3 to 6mg. In Great Britain the authorised algae form is limited to 8mg of astaxanthin a day for food supplements, the amount the European Food Safety Authority (EFSA) judged safe for adults in 2020. Take it with a meal that contains some fat.

• Read the astaxanthin figure, not the oleoresin figure. A label may say “astaxanthin oleoresin 100mg” with 5mg of astaxanthin inside. The 8mg limit refers to astaxanthin itself.
• Count every product. Krill oil, some fish oils, eye formulas and “skin” blends can all contain astaxanthin.
• Diet adds a little. EFSA’s safety assessment included astaxanthin from eating salmon, trout and shellfish on top of 8mg from supplements, and still found it safe for adults.

Is 12mg of astaxanthin too much?

12mg of astaxanthin a day is more than the 8mg a day authorised for food supplements in Great Britain, so a UK-compliant product shouldn’t provide it in its daily dose. A 2019 safety review of 87 human studies found no safety concerns with natural astaxanthin, including 35 studies at 12mg a day or more, but most were short. Sticking to 8mg or less is the sensible choice.

Is astaxanthin legal in the UK?

Yes. Astaxanthin-rich oleoresin from Haematococcus pluvialis algae is an authorised novel food in England, Scotland and Wales, for use in food supplements at up to 8mg of astaxanthin a day. It must be called “astaxanthin” on the label. It is the only astaxanthin entry on the FSA’s register of authorised novel foods (checked November 2026).

• Children: in a 2026 safety assessment, the Food Standards Agency (FSA) and Food Standards Scotland concluded the oleoresin is safe for adults and teenagers aged 14 and over, and recommended a label line saying younger children shouldn’t take it. EFSA had found that children under 14 taking 8mg a day could go over the safe intake.
• EU difference: since 2023 the EU has allowed lower doses for some younger age groups. Great Britain sets its own rules after Brexit, so UK products should follow the GB conditions.
• Synthetic astaxanthin: it is used in fish feed to colour farmed salmon. The authorised supplement form in Great Britain is the algae oleoresin.

Novel food rules exist because a food without a history of use in Europe before May 1997 needs a safety assessment first. For another example, see our guide to vitamin K2, and for how high-dose supplements add up, can you overdose on vitamins?

What are the benefits of astaxanthin?

The benefits of astaxanthin are not proven. Small trials suggest it may help skin moisture and wrinkles, ease screen-related eye strain and reduce a marker of muscle damage after exercise, but most studies are short, small and funded by astaxanthin makers. Reviews found no effect on cholesterol, blood sugar or exercise performance.

Does astaxanthin work for skin?

Astaxanthin may modestly help skin, but the evidence is thin. The 2021 review that found better moisture and fewer fine lines also warned that most trials were small, done mainly in healthy Japanese women, and often funded by companies selling astaxanthin. Sunscreen still does far more for sun damage than any supplement. For other skin options, see collagen supplements, vitamin C, which contributes to normal collagen formation for the normal function of skin, and reishi and skin.

Is astaxanthin good for your eyes?

Studies on astaxanthin and tired eyes are early. Most tested people with screen-related eye strain over a few weeks, some used combination products, and the makers often paid for them. If your eyes feel tired a lot, see our guides to heavy, tired eyes, dry eyes and whether blue light glasses work, and see an optician for any change in your sight.

Does astaxanthin help exercise recovery?

The best evidence is for a lower creatine kinase level after exercise, a blood marker of muscle damage. That isn’t the same as feeling less sore or performing better, and the same review found no gain in endurance or power. A 2024 review found bigger effects at 20mg or more a day, which is above the GB limit. Sleep, protein and rest matter more; see muscle recovery: how long it takes.

Which foods contain astaxanthin?

Wild salmon, trout, prawns, shrimp, crab, lobster, krill and salmon roe contain astaxanthin, because they eat algae or the small creatures that feed on it. Farmed salmon get it from colour added to their feed. The amount in a portion is far lower than a supplement dose, and varies a lot between wild and farmed fish.

Oily fish is worth eating for its omega-3 fats anyway: the NHS advises at least 2 portions of fish a week, 1 of them oily. Krill oil supplements contain small amounts of astaxanthin alongside EPA and DHA; see our omega-3 guide for krill oil vs fish oil. For a wider eating pattern, see the anti-inflammatory diet guide.

Astaxanthin side effects and who should avoid it

Astaxanthin is well tolerated by healthy adults at up to 8mg a day, and trials have reported few side effects. It hasn’t been tested properly in pregnancy, breastfeeding or young children, and studies on interactions with medicines are limited.

• Pregnancy and breastfeeding: there isn’t enough safety data, so avoid it unless your midwife or GP advises otherwise.
• Children under 14: the FSA’s 2026 assessment limits use to adults and teenagers aged 14 and over.
• Regular medicines: interaction studies are few, so check with your GP or pharmacist first, especially if you take blood thinners, blood pressure medicines or several medicines at once.
• Shellfish allergy: krill oil and shrimp-derived products carry a crustacean allergen warning. Algae astaxanthin doesn’t come from shellfish, but check the label.
• Stomach upset: take it with food; stop if it disagrees with you.
• Before surgery or a new diagnosis: tell your doctor about every supplement you take.

iIf you are taking astaxanthin for a health problem such as eye trouble, skin changes or tiredness, see your GP or optician first so the cause is found. Ongoing tiredness has many causes; our guide why am I always tired? covers the common ones.

How to choose an astaxanthin supplement

Choose an astaxanthin supplement that states the astaxanthin content in mg (not just the oleoresin weight), gives 8mg or less a day, names Haematococcus pluvialis as the source, and comes in an oil-based softgel. Avoid big “antioxidant” promises; no health claims are authorised for astaxanthin in Great Britain.

Comparing antioxidant supplements more widely? See our guides to resveratrol, coenzyme Q10, vitamin E, supplements for women over 40 and supplements for men over 50.