Astaxanthin (AX) is a natural chemical compound that belongs to the carotenoid group which are the most widely distributed pigments found in nature.  It is Astaxanthin that confers the rich pink color observed in various aquatic species including the salmon and crustaceans and even some nonaquatic species such as the flamingo.  The pink in the feathers of a flamingo is the result of eating food rich in AX (Fasset et al, 2009; Guerin et al, 2003; Higuera-Hussein et al, 2006; Pashkow et al, 2008).

Carotenoids also act as antioxidants, and research shows that AX is the most powerful antioxidant found in nature.  Antioxidants are substances that may prevent or delay some types of cell damage (Halliwell, 2007).  Antioxidants are found in many foods and in dietary supplements.

Tip:  When cells use oxygen to generate energy, free radicals are created because of energy production the mitochondria. These by-products are generally referred to as reactive oxygen species (ROS) as well as reactive oxygen and nitrogen species (RONS).  In chemistry, an atom, molecule, or ion, with one or more unpaired electron in its outer shell is called a free radical.

Your body needs a balance between antioxidants and free radicals. If free radicals overwhelm the body's ability to regulate them, a condition known as oxidative stress ensues which can lead to cell and tissue damage. Oxidative stress is a phenomenon caused by an imbalance between production and accumulation of oxygen reactive species (ROS) in cells and tissues, and the ability of a biological system to detoxify these reactive products via antioxidants (Gomez-Cabrera et al, 2009).

AX's ability to fight free radicals is 6000 times greater than vitamin C, 550 times than vitamin E and 40 times than beta-carotene (Miki, 1991; Goto et al, 2001; Nishida & Hamashita, 2007).

Tip:  Free radicals have a positive role as they can fight infections but must be in balance with antioxidants which are molecules that fight inflammation.

AX is not produced in the human body.  Humans commonly consume astaxanthin from seafood such as salmon, trout, shrimp, lobster, crab, and fish eggs. 

Anti-Inflammatory
Inflammation is a necessary biological response to harmful stimuli, such as pathogens, damaged cells, toxic compounds or irradiation (Medzhitov, 2010).  Inflammation is part of the healing process to mitigate the damage and restore health (Nathan & Ding, 2010). 

AX has properties that reduce inflammation in the body. In that regard, it is anti-inflammatory (Park et al, 2010), anti-cancer (McCall et al, 2018), anti-diabetic (Sila et al, 2015), and it has been reported to have beneficial gastro- (Kang & Kim, 2017), hepato- (Rao et al, 2015), neuro- (Feng et al, 2018), cardio- (Fasset & Coombes, 2011), ocular- (Hashimoto et al, 2013) and skin-protective (Davinelli et al, 2018) properties. 

For athletes, AX could potentially improve markers of exercise metabolism, performance, and recovery because of its potent antioxidant capacity.  Prolonged and strenuous physical exertion can create reactive oxygen species (ROS) which is a form of oxidative stress at the cellular level.  The ROS can overwhelm the antioxidant defense system, with detrimental impacts on normal physiological function (Davies et al, 1982; Borzone et al, 1994; Halliwell & Gutteridge, 1999; Banerjee et al, 2003; Powers et al, 2008; Peternelj & Coombes, 2011; Pingitore et al, 2015)

AX has been suggested to enhance exercise metabolism, performance, and recovery because of its potent antioxidant capacity.  Evidence to support this notion has been derived from studies using in vitro and in vivo animal models (Aoi et al, 2003; Liu et al, 2014).

In accordance with antioxidant activity, 12 weeks of AX supplementation has been demonstrated to improve total antioxidant capacity and decrease levels of inflammation in sedentary, obese subjects (Choi et al, 2011) and lower the levels of lipid peroxidation (free radicals) in healthy untrained males (Karppi et al, 2007).  

A human clinical trial on elite soccer players looked at whether AX can reduce free radical production after a 2-hour period of intense exercise. The treatment group took 4 mg of astaxanthin for 90 days.  They concluded that the astaxanthin prevented exercise-induced free radical production and prevented the depletion of antioxidant defense in young soccer players (Djordjevic et al, 2012). 

A recent study looked at mice who underwent high intensity interval training (HIIT) for six weeks while taking 10 mg/kg body weight of AX or placebo.  The training groups participated in 30 min/day high intensity interval training for 6 weeks.  Muscle samples were collected following the exercise training period.  The mice who received the AX during training, showed reduced oxidative stress and greater antioxidant capacity and mitochondrial growth (Wang et al, 2023).

The marker used by doctors to measure how much silent (also called “systemic”) inflammation is occurring in a person’s body is called C-reactive protein (CRP).

A double-blind, placebo-controlled human clinical trial was done to test the effect of AX on CRP levels in healthy volunteers. The subjects took either 12mg per day of AX or a placebo for eight weeks. CRP levels were measured before and after the eight-week supplementation period. Results were very good—in only eight weeks people taking AX reduced their CRP levels by over 20%; meanwhile, people taking placebo saw a slight increase in their CRP levels (Spiller et al, 2006a).

A company experimenting with AX production back in 2006 publicized a human clinical trial on patients with CRP levels that were high enough to place them in a high-risk category for cardiovascular disease. The patients took AX or placebo for three months, after which their CRP levels were again measured. Nearly half of the people taking AX fell out of the high-risk category while none of those taking placebo improved (Mera, 2006).

A team of researchers from Washington State University did a multi-faceted study on AX to test its effect on the human immune response. They used young women in this randomized, double-blind, and placebo-controlled study. They measured immune markers as well as DNA damage, oxidative stress levels and CRP. The results were positive on all markers. In fact, at a dose of only 2mg of AX per day they found a statistically significant decrease in CRP levels after eight weeks of supplementation (Park et al, 2010).

Natural AX is considered as a “superior antioxidant” because of its molecular structure and localization within the cell membrane, which increases the potency of astaxanthin compared to beta-carotene and vitamin E (Miki, 1991).

Muscle Health
The maintenance of skeletal muscle mass depends on the balance between muscle protein synthesis and muscle protein degradation (Gordon et al, 2013) Muscle atrophy occurs when the rate of protein degradation outweighs the rate of protein synthesis (Sandri, 2013). 

The effect of AX on muscle metabolism and performance is less clear in humans, with some showing a reduction in injury markers (Djordjevic et al., 2012) but not others (Bloomer et al., 2005). 

The effects of astaxanthin on muscle injury were studied among resistance-trained men (n=20, aged 25.1±1.6 years). The subjects were equally divided into the placebo (administered 1,732 mg safflower oil) or astaxanthin (administered 4 mg AX and 480 mg lutein) groups. After three weeks of assigned treatments, the participants were subjected to eccentric exercise (10 sets of 10 repetitions at 85% of one repetition maximum) and followed through 96 h post-exercise. The parameters measured in this study include muscle soreness, creatine kinase (CK) activity and muscle performance. A similar response in these variables was noted for both groups, reiterating that astaxanthin supplementation exerted negligible effects on skeletal muscle injury following eccentric loading. No significant difference was observed (Bloomer et al, 2005).

In contrast, thirty-two male elite soccer players participated in a random assigned double-blind study to determine whether astaxanthin supplementation reduced the oxidative stress and muscle damage induced from training.  One group received 4 mg AX for 90 days and other received a placebo.  Following supplementation, the athletes performed a 2-hour exercise bout after which blood samples were taken.  Those who received the AX showed reduced levels of exercise-induced muscle damage (Djordjevic et al, 2012).

Energy Metabolism
During exercise, the body has two main sources of fuel: carbohydrates and fat.  Studies show that astaxanthin can increase the use of fat as an energy source during exercise, which can lead to improved performance, endurance, and fat reduction.

During exercise, free radical-induced damage can alter the metabolism of fat, limiting the ability for fats to be oxidized as an energy source.  AX counters this and provides protection against the impact of free radicals on energy metabolism (Wolf et al, 2010; Kidd, 2011) and indirectly enhances fat metabolism (Aoi et al, 2008).

Prolonged AX supplementation has been reported to improve athletic performance in mice.  Male mice were given AX (1.2, 6, or 30 mg per kg body weight) by stomach intubation for 5 weeks to determine the effect of endurance capacity.  The AX group showed a significant increase in swimming time to exhaustion as compared to the control group. Blood lactate concentration in the astaxanthin group was significantly lower than in the control group.  AX treatment also significantly decreased fat accumulation. These results suggest that improvement in swimming endurance by the administration of astaxanthin is caused by an increase in utilization of fatty acids as an energy source (Ikeuchi et al, 2006).

8-week-old mice were treated with astaxanthin for four weeks, then ran on a treadmill.  Those who received AX showed increased fat utilization during exercise, and could run for a longer time, compared with mice on a normal diet.  The results suggested that AX promoted lipid metabolism rather than glucose utilization during exercise via CPT I activation, which led to an improvement of endurance and a reduction of adipose tissue with training (Aoi et al, 2008).

Increased Strength and Endurance Improvement in
Muscle contractions during exercise can lead to elevated levels of reactive oxygen species (ROS) in skeletal muscle, creating an imbalance in the body’s defenses against damage.  This imbalance and the elevated levels of ROS during muscular contractions contribute significantly to the reduction of the contractility force, an increase in muscular injuries, and speed up the fatigue processes (Purvis et al, 2010).

Research shows that AX can increase strength and endurance in athletes.  Researchers in Sweden conducted a 6-month clinical trial on young, healthy, male students between the ages of seventeen and nineteen.  Each subject took one 4 mg capsule per day with a meal for six months. The subjects’ strength was measured at the beginning of the experiment, halfway through (after three months), and again at the end of the experiment (af­ter six months) by counting the maximum number of knee bends to a 90º angle that each subject could do.  The results showed that, in six months, the students taking AX improved their strength and endurance by 62%.  The students taking a placebo increased their strength by 22%, which is normal for people in this age group over a six-month period, as they were generally involved in sports and physical activ­ity.  This means that the participants who receive the AX gain about 3 times faster in strength and endurance than their counterparts who received the placebo. (Malmsten & Lignell, 1998). This is the first study in humans to show that AX supplementation has a positive effect on physical performance.

Amateur endurance-trained males from 18 to 39 years of age who had a VO2 max > or equal to 50 ml/kg/mn and who actively participated in competitive cycling activities of at least 160 km per week were recruited. They took 4 mg/d of astaxanthin or placebo for 4 weeks.  The group who received the AX significantly increased power output and showed a 5% (2 min average) improvement in the time needed to complete the 20 km.  Their total time gains were accompanied by a 20 W increase (15 %) in the average power output generated by riders during the total time condition. Changes in time and power output for the placebo group were 0.8 % and 0.5 %, respectively.  At the end of 4 weeks, the placebo group showed no improvement in their cycling times. However, the cyclists taking natural astaxanthin were on average 5% faster. In addition, their power output increased by 15% (Earnest et al, 2011).

However, in another study of astaxanthin supplementation with endurance trained male cyclists, there was no improvement in either time trial or fat oxidization (Reis et al, 2013).  

Tennis elbow is a form of tendonitis that affects the arms. The repetitive motion of hitting tennis balls with a racket can cause a loss of grip strength in the hands and pain while gripping objects in the hand. A study of people suffering from tennis elbow, showed that those who took 12mg per day of natural astaxanthin for 8 weeks, doubled their grip strength in only 8 weeks. The average increase was 93%, to be exact, and there was also a decrease in the self-assessment of pain in their hands (Spiller et al, 2014).

Recreational runners were given 12 mg/day of astaxanthin for eight weeks. 14 males and 14 females, aged 42.  There was no improvement in maximal oxygen uptake (running VO2max) or maximal power output (cycling watts) with AX supplementation. However, subjects in the AX group showed a significant ~10% lower average heart rate at submaximal running intensities.  The AX appears to reduce the running heart rate at submaximal endurance intensities (Talbott et al, 2017).

A combination of AX supplementation (12 mg), tocotrienol (10 mg) and zinc (6 mg) along with interval-incline walking, improved muscle strength, size, and specific force in a healthy elderly population (Liu et al, 2018). 

Later, this formulation, in combination with endurance training, was given to a population of healthy, older adults (65-82 years).  Those who received the AX showed improved muscle endurance, increased fat metabolism, and increased exercise efficiency in males but not in females.  The metabolic improvements combined with the improvements in muscle size, strength and force strongly supports the addition of AX into an exercise training program (Liu et al, 2021).

Twelve recreationally trained male cyclists were recruited to take a placebo or 12 mg AX/day for 7 days, separated by 14 days of washout.  On day 7 of supplementation, the participants completed a 40 km cycling time trial on a cycle ergometer.  Those taking the AX showed a 1.2-2.9% improvement in their cycling time and had greater whole-body fat oxidation rate and a lower respiratory exchange ratio (Brown et al, 2020).

VO2Max
A Japanese study looked at the impact of AX on the autonomic nervous (ANS) and respiratory metabolism during different exercise intensities.  One group received 5 mg astaxanthin for two weeks while others took a placebo for two weeks, while working out on a treadmill.  The exercise load was in the form of running exercise on a treadmill at intensities of 30％, 50％ and 70％ of maximum heart rate. Those who received the AX showed improvements in respiratory metabolism and energy metabolism (Tajima & Nagata, 2004).

Recovery1
Vigorous intensity, exercise training sessions and competitive events are known to increase physiological stress on the tissue, resulting in muscle damage, oxidative stress, and inflammation (Leeder et al, 2012).  The stress may result from the damage directly induced by RONS or from damage induced through the inflammatory cascade.

A study looked at whether AX could help prevent the soreness that occurs after intense exercise. The young men who participated in this study were training regularly with weights. The subjects used a resistance training apparatus for strenuous knee exercises during the three-week treatment period and took either 4mg of AX or placebo every day.  The men taking placebo had significant joint pain in their knees immediately after performing the exercises. This pain was tested 10 hours after the heavy exercises, and then again at 24 hours and 48 hours after. Whether immediately afterward or at the various test times up to and including 48 hours afterward, the pain persisted for those who took placebo. But the men who were taking 4mg of Astaxanthin every day showed no change in knee soreness right after exercise. This pain-free state remained consistent at the three other test times of 10, 24 and 48 hours after exercise (Fry, 2001).

Another study with soccer players proved that astaxanthin reduced muscle damage and protected the function of cells during heavy exercise (Djordjevic et al, 2002)

A study of healthy volunteers using progressively heavier loads in a stepwise exercise were tested with 5 mg AX supplementation versus a placebo over two weeks. For those taking AX, metabolism during exercise became more efficient, respiratory-circulatory ability improved, and anti-fatigue and antioxidant profiles were augmented. These results led the researchers to conclude that recovery ability from exercise stress may be improved by taking AX (Nagata et al, 2003)

Forty elite soccer players in Europe took 4 mg of AX over a 90-day period, while a control group took a placebo. Those who received AX showed significant improvements in inflammation levels, immune system function, and most importantly for athletes, muscle recuperation.  The researchers concluded that AX “attenuates muscle damage, thus preventing inflammation induced by rigorous physical training.” They hypothesized that the mechanism of action may be that AX “protects the cell membranes against free radicals generated during heavy exercise, thus preserving the functionality of muscle cells (Baralic et al, 2015)

Another study looked at the effect of AX on delayed onset of muscle soreness (DOMS).  Nineteen resistance-trained men, mean age 22.6 completed a four-week supplementation period of 12 mg/day of either AX or placebo. Subjects completed four trials, with trials One and Three designed to induce muscle damage, Trials Two and Four were performance trials, conducted 48 h later and consisting of repetitions to failure at 65%, 70%, and 75% of 1RM.  Although performance was not affected (p > 0.05), AX supplementation significantly decreased subjective markers of delayed onset muscle soreness (p = 0.01) compared to the placebo. The results demonstrated that AX may enhance recovery by reducing DOMS without detriment to performance in resistance-trained men (Barker et al, 2023).

Immune Support
A new clinical study looked to see if AX could serve as a nutrition-based strategy to mitigate exercise-induced physiological stress.  Participants were randomized to receive AX or placebo trials, with supplements ingested daily for 4 weeks prior to running.  Blood samples were collected before and after supplementation, immediately post-exercise, and at 1.5, 3, and 24 hours, post-exercise.  The results showed that astaxanthin supplementation did not counter exercise-induced increases in plasma cytokines and oxylipins but was linked to normalization of post-exercise levels of numerous immune-related proteins within 24 hours. Thus, AX supplementation provided immune support for runners engaging in a vigorous running bout and uniquely supported 20 plasma immunoglobulins, including IgM (Nieman et al, 2023).

Reduced Fatigue
Lactic acid builds up during physical exertion and causes a burning sensation in the muscles and fatigue.  A study in Japan involved healthy adult men taking 6mg of AX daily for 4 weeks. Both the placebo and the AX group ran 1200m and had their lactic acid levels tested before and after running at the beginning of the study (before supplementation began).  They found a statistically significant reduction in exercise-induced lactic acid build-up in the men taking AX. The result was excellent: a 28.6% reduction in lactic acid on average from taking 6mg of AX per day for a month, which would allow for increased endurance (Sawaki et al, 2002).

A study examined the influence of one month of 12 mg daily Astaxanthin supplementation on heat tolerance and aerobic capacity. Astaxanthin improved exercise recovery but had no influence on performance in the heat. 22 male participants, age 23-26, received placebo or AX,  12 mg/day for 30 days.  They then walked for 2 hours in the heat at 40 °C, (104.0 °F)with 40% relative humidity on a 2% incline.  They were tested pre and post supplementation for a maximal oxygen uptake (VO₂ Max) test and the heat tolerance test (HTT).  The rise in blood lactate caused by the VO₂ Max test was significantly diminished in the group who received AX, improving exercise recovery (Fleischmann et al, 2019).

Dose
Recommended dosages vary in different countries range between 2 and 24 mg.  AX is marketed in the EU in multiple products at daily doses up to 12 mg and has been approved by national authorities around the world at daily doses up to 24 mg.  Human studies have not identified any significant toxicity at any doses, over any length of time for natural AX in at least 87 clinical trials involving 2,000+ participants using short-term daily doses (up to 100 mg) and long-term daily doses averaging between 8 and 12 mg. No severe adverse events have been recorded (Brendler & Williamson, 2019).

The most concentrated, naturally occurring source of AX is the astaxathin-producing microalgae Haematococcus pluvialis (Lorenz & Cysewski, 2000; Yuan et al, 2011). The best supplements use the AX that is extracted from this microalga. 

Synthetic astaxanthin is chemically different from natural astaxanthin, and functions differently in the body, meaning that you may not get the same outcomes.  Synthetic AX is manufactured in a lab from petrochemicals or petrochemical derivatives.  Synthetic AX has never been directly safety-tested in humans, and it has never been clinically tested to show any health benefit in humans (Capelli et al, 2013). 

The astaxanthin in Ultra K is made from Haematococcus pluvialis.  It is also microencapsulated, which protects the AX so that you get a 7x increase in bioavailability when compared to straight AX powder or resin. 

The recommended daily dosage of AX is 4-8 mg per day for normal health maintenance, with a higher dosage of 12 mg/day when used in therapy.  Also, athletes, particularly those doing high endurance activity, generally report better results at 12 mg/day (Capelli & Cysewski, 2013).

Table 1.  Recommendation dosage for different uses (Capelli, 2013).

Use	Use Recommended Dosage
Antioxidant	2-4 mg per day
Arthritis	8-12 mg per day
Tendonitis or Carpal Tunnel Syndrome	8-12 mg per day
Silent Inflammation (C-reactive protein)	4-12 mg per day
Internal Sunscreen	4-8 mg per day
Internal Beauty and Skin Improvement	4-8 mg per day
Immune System Enhancer	2-4 mg per day
Cardiovascular Health	4-8 mg per day
Strength and Endurance	4-12 mg per day
Competitive Athletes	8-12 mg per day
Brain and Central Nervous System Health	4-8 mg per day
Eye Health	6-8 mg per day
Topical Use	20-100 parts per million

 

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