August/September 2025 Issue
Ask the Expert: Astaxanthin
By Toby Amidor, MS, RD, CDN, FAND
Today’s Dietitian
Vol. 27 No. 7 P. 6
Q: My clients have been asking me about astaxanthin supplementation. Are there any research-backed benefits to taking this supplement?
A: Astaxanthin is a liposoluble nutrient naturally found in some plants and animals and is naturally synthesized by numerous microalgae, bacteria, and yeast.1 The microalgae Haematococcus pluvialis is used to make astaxanthin supplements for commercial use. Astaxanthin has been shown to have antioxidant and anti-inflammatory activity,1 which may be beneficial for health conditions such as heart, eye, brain, and skin health and helps support immunity. The following article will cover more information about astaxanthin, as well as research to back up some of its health claims.
About Astaxanthin
The carotenoid astaxanthin gives foods like wild salmon, prawns, crab, lobster, and shrimp their reddish color. It’s also used commercially in feed production for farmed salmon, trout, and shrimp and provides color to egg yolks and broiler chicken carcasses.1 The microalgae Haematococcus pluvialis synthesizes the highest amount of astaxanthin in nature, which makes it an optimal choice for commercial production as a supplement.
Antioxidant and Anti-Inflammatory Activity
Astaxanthin has antioxidant and anti-inflammatory properties. The carotenoid scavenges radicals from the surface of the cell and the interior of the phospholipid membrane.2 Astaxanthin’s oxygen radical absorbance capacity (ORAC) is 100 to 500 times higher than alpha-tocopherol, and it has a 10 times higher free radical inhibitory activity than related antioxidants (alphatocopherol, alpha-carotene, beta-carotene, lutein, and lycopene).2 Astaxanthin also has anti-inflammatory activity and may suppress some inflammatory cell signaling in vitro and in animal and human studies.3-5
Healthy Aging
Astaxanthin may play a role in healthy aging, including skin and brain health. Astaxanthin’s anti-inflammatory, immune-modulating, and DNA-repairing properties may help maintain skin health.6 Research supports that astaxanthin may help promote healthy skin by improving skin elasticity and moisture, and by reducing wrinkle formation.1,7
In addition, brain aging is associated with a decline in cognitive function and motility. In mice, astaxanthin was shown to cross the blood-brain barrier, which may have a healing effect on brain aging.8 Research shows that astaxanthin may help protect the central nervous system.9
Heart Health
Astaxanthin has been shown to help support heart health by reducing oxidative stress and inflammation, which play a role in CVD.10 A 2023 study focused on individuals with prediabetes and dyslipidemia who were supplemented with astaxanthin or placebo for 24 weeks. Astaxanthin treatment was associated with significantly lower LDL and total cholesterol, along with other CVD risk markers, compared with placebo.11
Eye Health
Numerous clinical trials showcase the potential role of astaxanthin in promoting eye health. Significant improvements were seen in various ocular diseases, including diabetic retinopathy, age-related macular degeneration, glaucoma, and cataracts.12 However, more long-term clinical trials are needed to define appropriate dosage and route of administration.
Immune Support
There are published studies that detail the improved immune response associated with short-term astaxanthin supplementation in animals and humans.13,14 One randomized, double-blind, placebo-controlled study in young healthy women receiving 2 mg or 8 mg of astaxanthin for eight weeks found an enhanced immune response with an increase in interferon gamma and interleukin-6 in subjects given 8 mg astaxanthin.14
Safety of Supplementation
Astaxanthin supplements are available in capsule, tablet, drop, and powder form. The FDA classified astaxanthin as GRAS when consumed within the recommended dosage. For optimal absorption, timing based on the method of consumption must be considered. Since astaxanthin is liposoluble, better absorption occurs with consumption of fat in foods like avocados, olive oil, nuts, and fatty fish.
Common side effects of supplementation may include gastrointestinal discomfort, increased frequency of bowel movements, red-colored stool, and mild stomach pain. There’s minimal risk of severe side effects, and although rare, severe allergic reactions can occur. Astaxanthin supplementation is cautioned in bleeding disorders, diabetes, autoimmune disorders, hypertension, low blood calcium levels, parathyroid disorders, and asthma. Additional caution is recommended for adults over 65 years of age and should be avoided in kids, pregnancy, and lactation. Like other carotenoids, accumulation and associated risks or side effects may be more common in supplement form compared with food form.
Recommendation for Dietetic Professionals
Astaxanthin has emerging evidence for a supportive role in health. In adults, the supplement form is considered rather safe when taken in recommended dosages with consideration of the above listed cautions. If a client asks about supplementation with astaxanthin, the health care provider should review basic astaxanthin information, look at contraindications, and stress the importance of using a third-party verified supplement and following listed instructions. The client should also seek medical attention if any signs of an allergic reaction occur, including difficulty breathing, itching, or rash development.
— Toby Amidor, MS, RD, CDN, FAND, is founder of Toby Amidor Nutrition (tobyamidornutrition.com) and a Wall Street Journal bestselling author. She’s written 11 cookbooks, including Up Your Veggies: Flexitarian Recipes for the Entire Family, Diabetes Create Your Plate Meal Prep Cookbook: 100 Delicious Plate Method Recipes, and The Family Immunity Cookbook: 101 Easy Recipes to Boost Health. She’s also a nutrition expert for FoodNetwork.com and a contributor to U.S. News and other national outlets.
References
1. Bjørklund G, Gasmi A, Lenchyk L, et al. The role of astaxanthin as a nutraceutical in health and age-related conditions. Molecules. 2022;27(21):7167.
2. Donoso A, González-Durán J, Muñoz AA, González PA, Agurto-Muñoz C. Therapeutic uses of natural astaxanthin: an evidence-based review focused on human clinical trials. Pharmacol Res. 2021;166:105479.
3. Choi SK, Park YS, Choi DK, Chang HI. Effects of astaxanthin on the production of NO and the expression of COX-2 and iNOS in LPS-stimulated BV2 microglial cells. J Microbiol Biotechnol. 2008;18(12):1990-1996.
4. Park CH, Xu FH, Roh SS, et al. Astaxanthin and corni fructus protect against diabetes-induced oxidative stress, inflammation, and advanced glycation end product in livers of streptozotocin-induced diabetic rats. J Med Food. 2015;18:337-344.
5. Baralic I, Andjelkovic M, Djordjevic B, et al. Effect of astaxanthin supplementation on salivary IgA, oxidative stress, and inflammation in young soccer players, evidence-based complement. Altern Med. 2015;2015:783761.
6. Singh KN, Patil S, Barkate H. Protective effects of astaxanthin on skin: recent scientific evidence, possible mechanisms, and potential indications. J Cosmet Dermatol. 2020;19(1):22-27.
7. Tominaga K, Hongo N, Fujishita M, Takahashi Y, Adachi Y. Protective effects of astaxanthin on skin deterioration. J Clin Biochem Nutr. 2017;61(1):33-39.
8. Fu M, Liang X, Zhang X, et al. Astaxanthin delays brain aging in senescence-accelerated mouse prone 10: inducing autophagy as a potential mechanism. Nutr Neurosci. 2023;26(5):445-455.
9. Fakhri S, Aneva IY, Farzaei MH, Sobarzo-Sánchez E. The neuroprotective effects of astaxanthin: therapeutic targets and clinical perspective. Molecules. 2019;24(14):2640.
10. Kato T, Kasai T, Sato A, et al. Effects of 3-month astaxanthin supplementation on cardiac function in heart failure patients with left ventricular systolic dysfunction—a pilot study. Nutrients. 2020;12(6):1896.
11. Ciaraldi TP, Boeder SC, Mudaliar SR, Giovannetti ER, Henry RR, Pettus JH. Astaxanthin, a naturalantioxidant, lowers cholesterol and markers of cardiovascular risk in individuals with prediabetes and dyslipidaemia. Diabetes Obes Metab. 2023;25(7):1985‐1994.
12. Giannaccare G, Pellegrini M, Senni C, Bernabei F, Scorcia V, Cicero AFG. Clinical applications of astaxanthin in the treatment of ocular diseases: emerging insights. Mar Drugs. 2020;18(5):239.
13. Fan Q, Chen Z, Wu Y, Zhu J, Yu Z. Study on the enhancement of immune function of astaxanthin from Haematococcus pluvialis. Foods. 2021;10(8):1847.
14. Park JS, Chyun JH, Kim YK, Line LL, Chew BP. Astaxanthin decreased oxidative stress and inflammation and enhanced immune response in humans. Nutr Metab (Lond). 2010;7:18.