What is astaxanthin?

Astaxanthin is a ketocarotenoid that marine organisms such as microalgae and phytoplankton make to protect themselves against environmental stressors. Larger organisms such as fish then eat these little critters, and astaxanthin accumulates in the tissues of the bigger animals. (Astaxanthin is the pigment that gives the flesh of salmon and other seafoods their pink color.) Astaxanthin is therefore a normal part of the human diet. 

Astaxanthin is a very stable and exceptionally potent antioxidant — for example, it appears to be hundreds of times more potent than α-tocopherol, a form of vitamin E. After consumption, it gets distributed to cells throughout the body and incorporated in cell membranes, mitochondria, and other cellular structures, where it helps protect cells and ultimately has a host of pro-longevity effects. 

Effects of astaxanthin on lifespan and healthspan 

Astaxanthin has been found to extend lifespan in several animals. Perhaps the most compelling of these experiments was done recently as part of the Interventions Testing Program (ITP), widely considered the gold standard of these types of tests. The ITP study in question found that astaxanthin extends average (median) lifespan in male mice by 12% when started at 12 months (middle age, for mice). There were no effects on female mouse lifespan, and this finding that only one biological sex benefited from a longer life is relatively common is this type of study. This is why Coastline contains ingredients shown to extend life in both males and females, respectively.

This work built on previous research showing that astaxanthin extends life in other organisms, including yeast, roundworms, and fruit flies experiencing high levels of oxidative stress. While the ITP study didn’t attempt to explain how astaxanthin prolongs life, these other experiments left some clues, and it appears that astaxanthin targets many of the hallmark processes that drive aging. 

To simplify how it exerts its other pro-longevity effects within cells, astaxanthin seems to increase the activity of several key proteins that each have various positive effects. One of the themes uniting several of the proteins astaxanthin acts on is that they help our bodies thrive during various stressors, such as Calorie restriction. For example, astaxanthin promotes the activity of a protein (“transcription factor”) named NRF2 that controls the expression of many genes involved in detoxifying foreign substances, clearing dysfunctional cellular components, and antioxidant defences. Astaxanthin’s stellar antioxidant actions help it protect structures against oxidative stress. For example, some astaxanthin is incorporated into both sides of cells’ membranes, protecting their fragile lipids against damage. It therefore makes sense that astaxanthin prolonged life in two studies of fruit flies with high oxidative stress burdens.

Then there’s FOXO3, a transcription factor activated by low food availability and hence low levels of insulin and IGF-1. In turn, FOXO3 helps animals hunker down and survive in times of scarcity, triggering beneficial processes such as repairing damaged DNA and eliminating cellular junk via autophagy. The aforementioned study of roundworms reported that astaxanthin’s pro-longevity effects relate to increased autophagy, finding astaxanthin might cause this by acting on the worm equivalent of FOXO3 and dialling down the growth-promoting insulin/IGF-1 and mTOR pathways. Consistent with this, astaxanthin supplementation has been found to increase expression of autophagy-related genes in people with type-2 diabetes.

Astaxanthin influences the activity of SIRT1, a nutrient-sensitive enzyme that also interacts with FOXO3. SIRT1 is a member of a family of enzymes that removes acetyl tags from proteins (they “deacetylate” them), including the histones that compact DNA. Since histones influence whether genes can be expressed, SIRT1 affects the expression of various genes implicated in aging, including genes involved in DNA repair and inflammation. SIRT1 is among a group of enzymes that act on PGC-1α, a protein that helps activate a set of transcription factors that increase the burning of fat and glucose, promote the generation of new mitochondria, and keep tabs on oxidative stress. 

AMP kinase is another nutrient-sensitive enzyme that feeds into PGC-1α, serving as a key coordinator of how cells respond to low levels of circulating nutrients. For example, AMP kinase inhibits mTOR, improves how cells respond to the storage hormone insulin, and promotes autophagy. Astaxanthin appears to increase AMP kinase activity too. 

As well as influencing mitochondria indirectly through the above proteins and others, astaxanthin pitches up in mitochondria and then guards them against free-radical induced damage. It further helps with mitochondrial quality control in other ways, all of which counter mitochondrial dysfunction. 

The mechanisms mentioned above don’t detail all the ways by which astaxanthin is thought to promote longevity, but hopefully they give you an idea of the diversity of astaxanthin’s beneficial actions and how it seems to target most of the hallmarks of aging, including chronic inflammation, deregulated nutrient sensing, epigenetic alterations, disabled macroautophagy (and hence loss of proteostasis), genome instability, and mitochondrial dysfunction. Astaxanthin seems to be doing a lot of good stuff!

Positive effects of astaxanthin on human health

While there have been several experiments reporting that astaxanthin enhances outcomes not detailed below (for example, exercise endurance performance), these studies have used products containing other active ingredients, so it’s not really possible to attribute the positive effects to astaxanthin per se. In the meantime, here are some positive beneficial effects that we can attribute directly to astaxanthin. 

Astaxanthin improves cardiovascular health and reduces chronic inflammation

There have now been enough studies on the effects of astaxanthin on cardiovascular and metabolic health to do a “meta-analysis”, a systematic compilation of data from multiple studies to try to identify what the overall body of literature shows. One of these focused on the effects of astaxanthin on people at risk of the “metabolic syndrome”, a constellation of risk factors that dispose people to diseases such as diabetes. Overall, the analysis showed that astaxanthin intake has small positive effects on cardiovascular risk by slightly reducing total cholesterol and blood pressure while the heart contracts (systolic blood pressure), and more substantially decreasing LDL cholesterol. 

Oxidative stress and chronic inflammation also have causal roles in cardiovascular disease and aging, and other research has shown that astaxanthin helps fight oxidative stress and chronic inflammation. Much of this research has focused on malondialdehyde, a blood marker generated by oxidative damage to polyunsaturated fats. Malondialdehyde can then itself run amok, damaging proteins by crosslinking with them and forming advanced lipoxidation end products (ALEs). Like the advanced glycation end products you might have read about elsewhere on this site, ALEs disrupt proteins’ functions. Returning to astaxanthin, another meta-analysis found that astaxanthin consistently reduces malondialdehyde. While effects of supplementation on other markers of oxidative stress have been less comprehensively tested, there’s also evidence astaxanthin reduces levels of another marker of oxidative damage to fats (isoprostane), increases antioxidant defences (superoxide dismutase), and reduces a marker of chronic inflammation (interleukin-6). 

Astaxanthin supports reproductive function in people with reproductive issues

Nowadays, difficulty getting pregnant is quite common, and in many cases it’s hard to pinpoint precisely why couples are struggling to conceive. In some cases of this type of “subfertility”, astaxanthin might be helpful, for both women and men. 

Regarding women, several clinical trials have given women with polycystic ovary syndrome (PCOS) astaxanthin at doses ranging from 6 to 16 mg per day. The results have been impressively positive, showing that astaxanthin improves egg (oocyte) maturation and reduces markers of oxidative stress and inflammation in women undergoing assisted reproduction, even at 6 mg per day. While there are some discrepancies between studies, this research has consistently found astaxanthin boosts women’s cardiovascular and metabolic health and egg cell quality, even if actual fertility and PCOS symptoms do not always improve. 

Regarding men, this is one of those rare instances where more studies have been done on their female counterparts. There has been a clinical trial showing that 16 mg astaxanthin per day for 3 months reduced semen oxidative stress, increased sperm velocity, and even increased the rate at which couples successfully conceived. A more recent study didn’t recapitulate these findings, however, so let’s watch this space!

Astaxanthin improves cognitive function

There is a little evidence that astaxanthin can enhance cognition. When healthy adults took 12 mg astaxanthin daily for 12 weeks they had more accurate short-term (“working”) memory and faster reaction times in a test of attention. While this research is preliminary, there are many reasons to think astaxanthin will prove to be excellent for brain health. For example, experiments on rats have shown that astaxanthin readily crosses the blood-brain barrier and accumulates in the brain. It then protects the brain against oxidative stress-induced damage. A study of rats found that astaxanthin increases activity of key antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and boosts mitochondrial function in the aging brain by increasing the gradient of protons on either side of the mitochondrial membrane. This gradient is used to generate ATP, the “energy currency” of cells. There’s also evidence that astaxanthin might help the brain remodel itself to cope with changing demands. 

Astaxanthin improves skin health

Like lutein and zeaxanthin, astaxanthin is a carotenoid that has been shown by several studies to support skin health. For example, supplementing just 4 mg astaxanthin each day for 9 weeks protected people’s skin against photodamage, helped maintain skin hydration during UV radiation exposure, and left users reporting their skin was smoother. In another study, 6 or 12 mg astaxanthin for 16 weeks prevented deterioration in skin dryness and wrinkles, which worsened in the placebo group. And while there haven’t yet been many studies, a meta-analysis of astaxanthin’s skin-protecting effects reported that supplementation restored skin moisture and improved skin elasticity.

Our use of astaxanthin

Regarding astaxanthin dose, we use 6 mg, a quantity at least as high as the lowest dose used in clinical trials to improve each of the health outcomes listed above. This dose has also been studied in conjunction with lutein and zeaxanthin.

Regarding timing, astaxanthin is in the Coastline SoftGels. Honestly, we don’t think the timing of when you take these matters significantly. Some of our team members take these in the morning based on a speculative rationale related to roles of the ingredients in the gel capsules on mitochondrial function and oxidative stress. Other team members, however, take them in the evening for convenience because they prefer to take all their capsules at once. The choice is yours! 

Regarding the form of astaxanthin we use, the product is sourced from a type of microalgae named Haematococcus pluvialis. Based on chemistry, there are reasons to think that natural astaxanthin sources like the one we use are superior to synthetic ones. Since astaxanthin is lipid soluble, the astaxanthin we use is suspended in oil to improve its bioavailability. 

Astaxanthin typical dietary intakes and safety

As mentioned above, astaxanthin is present in foods from the sea, including seaweed, crustaceans, fish, and others. The concentrations of astaxanthin in these sources can vary widely, but to give you an idea of their astaxanthin contents, 100 g salmon typically provides about 2 mg astaxanthin.

Astaxanthin has a fine safety profile, even at doses above 12 mg per day, twice the dose in Coastline. The European Food Safety Authority has deemed sustained astaxanthin supplementation to be perfectly safe at doses up to 8 mg per day.