What is astaxanthin?

Astaxanthin is a red-orange carotenoid pigment naturally present in various marine organisms, including microalgae, crustaceans and fish, such as salmon. It is renowned for its powerful antioxidant properties, surpassing those of many other similar substances. Thanks to its ability to neutralise free radicals, astaxanthin is beneficial for skin and eye health and the immune system. It is also used in food supplements for its potential effects on reducing inflammation and improving athletic performance. Its growing popularity stems from its many health benefits.

Numerous studies have been conducted on the benefits of astaxanthin. Above all, it is its antioxidant and anti-inflammatory properties that give it beneficial effects in preventing or helping to combat certain diseases and/or disorders in which oxidative stress and inflammation are involved.

Reactive oxygen species, when present in excess in our bodies, cause damage to cellular components, such as DNA, lipids and proteins, leading to various diseases. Our bodies are equipped to defend themselves against oxidising species, but they can be overwhelmed by too many reactive oxygen species. This is where exogenous antioxidants can play an essential role in combating oxidative stress. Astaxanthin is considered to be a powerful antioxidant[3]. Among multiple carotenoids, including lycopene, β-carotene and lutein, astaxanthin has shown the highest antioxidant activity[4]. Its antioxidant power is far greater than that of vitamin C and vitamin E. Astaxanthin owes its exceptional antioxidant properties to its unique molecular structure. It also has the advantage of never becoming a pro-oxidant, unlike vitamin E, which can promote oxidation in high doses.

A meta-analysis of 12 randomised controlled trials involving 380 participants[5] showed that astaxanthin supplementation reduced blood levels of malondialdehyde, a compound produced by lipid peroxidation and used as a marker of oxidative stress.

Astaxanthin's powerful antioxidant properties enable it to combat the signs of ageing, particularly with regard to skin health and the functioning of the central nervous system[6]. Astaxanthin can compensate for the reduced effectiveness of the antioxidant defence system during the ageing process, helping to combat the damage caused by oxidative stress.

Astaxanthin has anti-inflammatory properties, mainly because it has the ability to act on the expression of inflammatory cytokines. These anti-inflammatory properties are beneficial and could be put to good use in a number of diseases caused by chronic inflammation. Additionally, by acting on inflammation, astaxanthin has been shown to have beneficial effects in animal models or cell lines as a neuroprotective compound in Alzheimer's and Parkinson's disease, as well as on eye and skin health. Astaxanthin is also thought to protect the liver and kidneys, as well as prevent atherosclerosis[7].

Randomised controlled trials have corroborated these results and confirmed astaxanthin's ability to fight inflammation. For example, taking 2 mg of astaxanthin a day for 8 weeks reduced plasma levels of C-reactive protein, a marker of inflammation, in young women in good health. At a dose of 8 mg/day, astaxanthin stimulates the immune system[8].

According to an experimental study, astaxanthin is capable of modulating lymphocyte immune responses[9]. In a randomised controlled trial[10], researchers noted an improvement in the immune response of healthy female participants who had received daily astaxanthin supplementation for 8 weeks.

Studies report that astaxanthin can improve the general appearance of the skin, helping it to combat damage caused by external stressors, as well as relieving certain skin conditions. Astaxanthin can build up in the skin[11].

Sun exposure also subjects the skin to stress, particularly by encouraging the build-up of reactive oxygen species in the dermis and epidermis. Chronic exposure to the sun's ultraviolet rays contributes to sun-related skin ageing, clinically characterised by dryness, pigmentation, sagging skin and deep wrinkles[12].

Astaxanthin supplementation helps prevent skin ageing by improving hydration and elasticity, according to the results of a meta-analysis[13]. Another meta-analysis[14] reported similar results, concluding that a dose of 3 to 6 mg/day of astaxanthin could protect against skin damage caused by UV exposure.

In a study conducted on mice[15] suffering from atopic dermatitis, astaxanthin supplementation reduced skin irritation, inflammation and itching.

Astaxanthin can also be applied to the skin. One study[16] evaluated the effect of the combination of oral supplementation and topical administration of astaxanthin. A number of improvements in the appearance of the skin were observed, notably wrinkles, age spots, skin elasticity and texture, and the water content of corneocytes, the outermost layer of the skin. The combination of the two methods of administration amplifies the cosmetic effects of astaxanthin.

A powerful antioxidant, astaxanthin also offers significant hair health benefits. By protecting cells from free radical damage, it helps to maintain healthy hair and strengthens its structure. Astaxanthin's anti-inflammatory properties may also play a role in reducing scalp inflammation, promoting an environment conducive to hair growth.

Multiple scientific articles suggest that astaxanthin is capable of preserving cognitive function. In a study conducted on mice, astaxanthin supplementation encouraged new neurons to form in the hippocampus, an area of the brain involved in memory[17]. Researchers also noted that astaxanthin improved spatial memory in mice. Astaxanthin's neuroprotective properties are linked to its antioxidant and anti-inflammatory properties, but also to its ability to maintain neuronal plasticity[18].

A randomised controlled trial[19] conducted on people complaining of memory loss concluded that astaxanthin supplementation at doses ranging from 6 to 12 mg/day for 12 weeks improved certain cognitive parameters.

Oxidative stress and inflammation are implicated in the development of cardiovascular disease. Astaxanthin is effective in combating both these phenomena[20]. In addition, one study[21] reported that astaxanthin had beneficial effects in preventing atherosclerosis - a cardiovascular risk factor - thanks to its antioxidant potential and anti-inflammatory properties[22], as well as its ability to slightly reduce blood sugar levels[23] and improve lipid profiles[24].

A meta-analysis of 7 studies involving 321 participants[25] suggests that astaxanthin may improve certain markers of metabolic syndrome, which is in itself a risk factor for cardiovascular disease. However, the researchers conclude that their results need to be consolidated by other studies.

Astaxanthin has been tested in top-level footballers. Supplementation for 90 days reduces the production of reactive oxygen species during physical training and strengthens the antioxidant defence system, thereby reducing muscle damage[26]. Its consumption is also recommended as part of sports nutrition.

The gastrointestinal mucosa is constantly exposed to various sources of oxidative stress and inflammation, such as bacterial infections (Helicobacter Pylori), chronic alcohol consumption, smoking and non-steroidal anti-inflammatory drugs. Oxidative stress and inflammation are implicated in the development of gastrointestinal disorders (gastric ulcer, ulcerative colitis, gastric cancer, colorectal cancer, etc.). One article[27] listed the studies conducted on the impact of astaxanthin on gastrointestinal health. The authors came to multiple conclusions: astaxanthin could improve gastric ulcers by modulating the immune response and reducing oxidative stress, particularly when linked to the presence of Helicobacter Pylori bacteria; astaxanthin appears to inhibit cancer cell growth and metastasis (in experimental models of stomach and colon cancer) by modulating signalling pathways linked to cell spread and apoptosis. Finally, the authors reported a beneficial effect of astaxanthin on ulcerative colitis, a chronic inflammatory bowel disorder, thanks to its antioxidant and anti-inflammatory properties.

Astaxanthin's exceptional properties mean it has a positive impact on eye health[28]. Multiple studies suggest its possible beneficial effects for preventing and treating eye diseases, in particular dry eye syndrome and age-related macular degeneration. In a study of 60 people, astaxanthin supplementation at a dose of 6 mg twice a day improved the symptoms of dry eye syndrome[29]. Taking an antioxidant supplement containing astaxanthin increases tear production and improves the stability of the tear film needed to protect the eye. Researchers have noted a reduction in the level of reactive oxygen species present in tears when antioxidants are administered orally[30]. A number of studies have also shown a beneficial effect of supplementation with a mixture of antioxidants - including astaxanthin - on certain symptoms of AMD.

Laboratory studies on cells and animal models suggest that astaxanthin has anti-cancer properties. In colorectal cancer, melanoma and gastric carcinoma cell lines, astaxanthin has been shown to induce apoptosis - the mechanism by which cells destroy themselves. Astaxanthin also appears to restrict spreading in numerous experimental models and could improve the efficacy of conventional chemotherapeutic drugs on tumour cells[31].

All these results need to be confirmed in clinical trials.

Natural astaxanthin has a higher antioxidant activity than synthetic astaxanthin, and is currently considered to be the only effective and safe source for human consumption[32]. It is obtained by extraction after cultivating the algae in bioreactors. The green microalga Haematococcus pluvialis builds up a high astaxanthin content under stressful conditions, such as high salinity, nitrogen deficiency, high temperature and light[33],[34].

Astaxanthin is mainly found in natural sources, such as the green alga Haematococcus pluvialis, the red yeast Phaffia rhodozyma, wild salmon and certain shellfish. Organic farming guarantees the highest quality astaxanthin, with no residues of pesticides or other undesirable substances.

The ideal period for a course of astaxanthin can vary according to individual needs. Some people choose to take it during periods of intense sun exposure to boost protection against UV-induced damage. Others opt to take it regularly to enjoy its ongoing benefits.

Astaxanthin-rich oleoresin from the algae Haematococcus pluvialis is authorised for use in food supplements at doses ranging from 40 to 80 mg/day, corresponding to a maximum dose of 8 mg of astaxanthin per day. This dose is considered safe and takes into account any dietary intake, whose high estimate is 0.06 mg/kg body weight per day[35] for an adult.