Astaxanthin: Uses, Side Effects, Precautions, and More

Astaxanthin is a pigment (colored compounds used to color other substances) typically found in water-living organisms. Still, it can be found in other living things, such as algae, salmon, and shrimp.

Astaxanthin is a carotenoid (multicolored organic pigments that plants and algae produce). More specifically, astaxanthin can be classified as a ketocarotenoid (a ruby-reddish carotenoid).

However, unlike beta-carotene (an orange-yellow carotenoid), it doesn't possess vitamin A activity.

Instead, astaxanthin might have some potential antioxidant and anti-inflammatory effects that are likely responsible for how it works.

This article will discuss what you should know about astaxanthin, including its potential uses, side effects, interactions, and more.

Dietary supplements are not regulated in the same way drugs are in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Choose a supplement tested by a trusted third party, such as the U.S. Pharmacopeia (USP), ConsumerLab.com, or NSF, whenever possible.

However, even supplements that are third-party tested are not necessarily safe for all or effective in general. Therefore, talking to your healthcare provider about any supplements you plan to take and checking in about potential interactions with other supplements or medications is important.

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider.

No supplement is intended to treat, cure, or prevent disease.

While more extensive research is necessary regarding effectiveness, astaxanthin is sometimes used to treat various health conditions.

Research is most robust for its effect on the following:

Oxidative stress might have a huge role in several brain-related health conditions, such as Alzheimer's disease (AD).

In general, oxidative stress is when there aren't enough naturally occurring antioxidants in your body to attack unstable molecules known as free radicals.

Free radicals can damage components (parts) within the body, including the hereditary material DNA.

Per a review article, a clinical trial studied astaxanthin in a few healthy older adults.

In this clinical trial, older adults in the astaxanthin group had fewer errors in maze tests and experienced quicker reaction times in computer-based memory and thinking tests. These results suggest that astaxanthin may improve brain function.

In another clinical trial discussed in the review article, middle-aged study participants in the astaxanthin group performed better on word memory tests. However, there were no differences in performance between the astaxanthin and placebo groups (people given an intentionally ineffective drug) for participants over 54 years old.

Additionally, from the same review article, other studies showed that astaxanthin improved hand-eye coordination, information processing, and mental or physical fatigue (excessive tiredness).

Even with these encouraging results, it is still challenging to quantify astaxanthin's effects.

This is because, in all but one study, astaxanthin was combined with another supplement called sesamin (a fat-reduction supplement from the bark of Fagara plants and sesame oil). This makes it difficult to determine which substance may have been responsible for the positive results.

According to another study in the review article, results suggested that astaxanthin might prevent dementia by lowering phospholipid hydroperoxide (PLOOH) levels in middle-aged and older adults. PLOOH builds up abnormally in the red blood cells (RBCs) of people with AD and dementia.

Drawbacks in these trials include the small number of participants and the combined use of astaxanthin with sesamin. And results of one study suggested that astaxanthin didn't help people older than 54 on word memory tests.

For these reasons, more rigorous and standardized research with higher quality and more extensive clinical trials is still needed.

Oxidative stress might play a role in several eye conditions, such as cataracts (cloudy vision) and age-related macular degeneration (AMD).

AMD is a vision-threatening condition that tends to affect people over 50—especially those older than 65.

In AMD, blood leaks into the macula, which is the center of the retina in the back of the eye. The macula helps you see fine details.

Per a review article, small studies showed that astaxanthin improved blood flow in different parts of the eye—like the retina in the back of the eye—when compared to placebo (a substance with no medicine in it).

The article included other small clinical trials, which showed that astaxanthin improved visual sharpness and deep vision compared to a placebo.

While there were mixed results when it came to eye strain, results from a study in a review article showed that astaxanthin helped with eye accommodation. Eye accommodation is switching focus from far away to nearby objects.

Although promising, many of these studies were small and sometimes reflected conflicting results.

Therefore, additional, rigorous research with higher quality and more extensive clinical trials is still necessary to better understand astaxanthin's effects.

A review article included a small clinical trial that studied astaxanthin in people with mildly high cholesterol.

And in the study, the participants in the astaxanthin group experienced an increase in high-density lipoprotein (HDL) cholesterol ("good cholesterol") levels and a decrease in triglycerides.

The review article also mentioned another small study. And in this clinical trial, the astaxanthin study participants had a reduction in low-density lipoprotein (LDL) cholesterol ("bad cholesterol") when compared to the placebo group.

Although the results are positive, there are few human studies. And the available human studies have been small and short-term.

Therefore, additional high-quality research with extensive and longer-term clinical trials is warranted.

According to a review article, there are a limited number of human studies on astaxanthin for the potential benefit of immune support.

But based on the few small clinical trials in humans, these results showed that astaxanthin increased the activity of the immune system.

Since there are only a few small studies, additional higher-quality research with a larger group of people is warranted.

Per a review article, astaxanthin might support skin health with potential antioxidant effects, which may protect the skin from UV-related oxidative stress.

The same review article also mentioned several small studies that supported astaxanthin for skin health.

When compared to a placebo, astaxanthin resulted in the following:

While these results are positive, further extensive research with more significant and higher-quality clinical trials is still warranted.

As with many medications and natural products, astaxanthin supplements may have side effects.

Astaxanthin is generally safe with no side effects when taken with food.

The FDA has placed astaxanthin on the GRAS (generally recognized as safe) list.

But astaxanthin is only GRAS at 6 to 7 milligrams (mg) daily. It must also come from one of the following two organisms (living things):

However, common side effects of astaxanthin might typically include digestive system-related symptoms, such as diarrhea.

Based on a review article, no severe side effects were seen—even at high doses. At high doses, however, some side effects may include:

Aside from these, a severe allergic reaction is a profound side effect possible with any medication or natural product.

If you're having a severe allergic reaction, symptoms may include breathing difficulties, itchiness, and rash.

If any of your symptoms feel life-threatening, call 911 and get medical help right away.

A healthcare provider may advise against astaxanthin use if any of the following applies to you:

Severe allergic reaction: Avoid astaxanthin if you have a known allergy to it or its ingredients or parts. If you need clarification on whether it's safe, ask a registered dietitian, pharmacist, or healthcare provider for more information.

Pregnancy: There is one study regarding the use of astaxanthin as a pretreatment to improve fertility treatment outcomes in people with endometriosis (a condition in which tissue similar to that lining the uterus grows outside the uterus).

Otherwise, there is little information about the effects and safety of astaxanthin in pregnant people and the unborn fetus. Pregnant people typically are not mentioned on product labels.

Reach out to a healthcare provider to discuss the benefits and risks of astaxanthin if pregnant.

Breastfeeding: There is limited information about the effects and safety of astaxanthin on breastfeeding parents and nursing babies. Moreover, most astaxanthin product labels are unlikely to target breastfeeding parents. Before using astaxanthin, discuss its benefits and risks with a healthcare provider.

Adults over age 65: Older adults have participated in astaxanthin-related clinical trials. Still, caution should be used with astaxanthin in older adults, since this population traditionally has a higher likelihood of medication side effects.

Children: There is little information about the impact and safety of astaxanthin in children. Furthermore, since astaxanthin product labels target adults and not infants or children, the supplement is likely not intended for this age group. Consult with a healthcare provider if you're considering astaxanthin for your child.

Animals: Too much astaxanthin may build up in the eyes and skin, causing the skin to look yellow or red. Before giving astaxanthin to animals, contact a veterinarian to discuss the benefits and risks.

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

While there are some studies on astaxanthin in humans, more research with high-quality clinical trials is still necessary.

For this reason, there are no guidelines on the appropriate dosage to use astaxanthin for any condition. But astaxanthin doses may be between 2 mg and 24 mg in different countries.

The specific dose may vary based on the dosage form and medical condition.

Follow a healthcare provider's recommendations or product label instructions if you use astaxanthin.

As mentioned, astaxanthin is generally safe, causing no side effects when taken with food.

The FDA recognizes astaxanthin as safe at 6 mg or 7 mg doses taken daily. And there were no safety concerns at dosages above 11 mg per day.

Astaxanthin has a good safety profile at short-term daily doses of up to 100 mg and long-term daily doses between 8-12 mg. But if you take too much astaxanthin, side effects may include red-colored stool (poop) and frequent bowel movements.

If you suspect you are experiencing life-threatening side effects from too much astaxanthin, seek immediate medical attention.

Astaxanthin might interact with the following medications:

It is essential to carefully read a supplement's ingredient list and nutrition facts panel to know which ingredients and how much of each element is included. Please review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

Storage instructions may vary for different products. Carefully read the directions and packaging label on the container.

Most medicines' optimal storage condition is in a cool and dry place. You should also keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet.

Discard after one year or as indicated on the packaging. Avoid putting unused and expired products down the drain or in the toilet. Visit the FDA website to learn where and how to discard all unused and expired medications. You may also be able to find disposal boxes in your area.

Ask a pharmacist or healthcare provider if you have any questions about how to dispose of your medications or natural products.

If you plan to travel with astaxanthin, get familiar with your final destination's regulations. The U.S. Embassy website might be a helpful resource.

Ask a healthcare provider how to travel with your medications or natural products if necessary.

Astaxanthin may affect brain health, eye health, high cholesterol, immune support, and skin health.

Oher potentially similar supplements include:

Only combine multiple natural products once you first talk with a healthcare provider, pharmacist, or dietitian. Checking in can help you avoid possible harmful interactions and side effects and ensure you're giving these supplements a fair trial at appropriate doses.

Astaxanthin supplements are available in a few different dosage forms—with capsules potentially being the most common.

Yes. Manufacturers in the United States make astaxanthin supplements.

To safely take herbal medications—like astaxanthin—inform your healthcare providers and pharmacists about all medications you take.

This includes over-the-counter (OTC), herbal, natural medicines, and supplements.

They can help prevent possible interactions and side effects. They can also ensure you’re given astaxanthin a fair trial at appropriate doses.

There are a few different sources of astaxanthin.

Astaxanthin is a carotenoid and pigment (natural coloring) typically found in water-living organisms, such as lobster, shrimp, and salmon.

You may also find astaxanthin added to food.

Astaxanthin supplements are commonly available in capsule form.

Other dosage forms of astaxanthin, which may contain other ingredients, include:

You may be able to find vegetarian and vegan options.

The product that works for you will depend on personal preferences and your desired results. Each product may work a bit differently, depending on the form.

Following a healthcare provider's recommendations or label directions is essential.

Astaxanthin is a carotenoid and pigment typically found in water-living organisms. Astaxanthin may have potential uses in brain health, eye health, high cholesterol, immune support, and skin health.

Before using astaxanthin, involve a registered dietitian, pharmacist, or healthcare provider in your decision-making process.

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By Ross Phan, PharmD, BCACP, BCGP, BCPSRoss is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.