There are a number of reason why people may start including astaxanthin into their dietary regimen.
The main functioning mechanisms are its antioxidant and anti-inflammatory activity which can benefit various areas of health.
While there are many, here are the most prominent and well-researched reasons of them all:
1. Astaxanthin Fights Metabolic Syndrome
Various age-related chronic diseases can be traced to a cluster of disorders referred to as metabolic syndrome.
This includes concerns like hypertension, insulin resistance, elevated cholesterol and obesity among others.
In this scenario, astaxanthin supplementation can help lower blood glucose levels and reduce insulin resistance.
Astaxanthin also holds the potential to scavenge free radicals which damage lipids and lower insulin sensitivity.
At the same time, it also preserves the ability of the pancreas to manufacture more insulin on its own. 
2. Astaxanthin Enhances Brain Health
Some research has linked the antioxidant activity of astaxanthin to neuroprotective functioning.  
Because oxidative stress is a normal part of aging and is linked to many disease conditions, astaxanthin supplementation is seen as helpful in reducing markers of oxidative damage.
For instance, both Alzheimer’s and dementia are conditions linked to oxidative stress.
Some studies suggest that astaxanthin can help preserve neural functioning in middle and elderly subjects. 
However, study samples for this research are small and more investigation is needed.
3. Cardioprotective Benefits
Another area where research seems promising is boosting heart health.
Most of the concerns in this area arise from oxidative stress and inflammation and astaxanthin seem to offer some much-needed help. 
Areas of cardiovascular health it seems to impact include blood pressure, atherosclerosis, and cholesterol levels.
This carotenoid is believed to promote blood flow due to its antioxidant properties as excessive oxidization can be responsible for impaired blood flow.
Animal studies show oral administration of astaxanthin in hypertensive rats resulting in reductions in BP.
Another study investigated the effects of astaxanthin on overweight and obese adults with results suggesting supplementary astaxanthin having a positive effect on LDL cholesterol levels and oxidative stress biomarkers. 
4. Skin Benefits
Alongside brain and heart health, astaxanthin also provides benefits to the skin.
Not only does it enhance the appearance of the skin, but may also hold the potential to treat specific skin conditions.
A topical application of this carotenoid seems to improve skin elasticity and symptoms of skin aging. 
Its skin health-boosting properties also include its potential to increase skin moisture, moisture retention and promote smoothness.
Astaxanthin also has UV blocking properties offering protection against sun-related damage. 
And if you refer back to the earlier point of astaxanthin promoting blood flow and circulation, it translates to helping the skin have improved circulation as well.
This activity helps the skin by increasing cell turnover, amplified elasticity, and increased water retention.
5. Astaxanthin Reduces Exercise-related Fatigue
Astaxanthin has also shown potential in improving energy levels and reducing post-exercise fatigue.
Athletes at any level need a reliable source of energy to keep performing at their peak.
The challenge arises when athletes work their muscles hard and cell-damaging substances called free radicals are produced.
When the level of free radicals becomes excessive, with the body being unable to keep up and detoxify or eliminate the damaging substances, you get in a state of oxidative stress.
Being an athlete, your body undergoes inflammation along with muscle soreness, fatigue, weakness, and pain.
Astaxanthin supplementation can help manage this cumulative effect of oxidative stress.
It does so by preventing the body from overproducing free radicals and getting the balance right.
If you exhaust yourself times and again, you become more liable to cause muscle and tissue damage.
But if you work hard enough to regulate the expression of cell-defending antioxidants in the face of free radicals with some help from astaxanthin, your body learns to cope with the oxidative stress of exercise.
At the same time, exercise also depletes your glycogen stores leading you to fatigue quickly. But with astaxanthin supplementation, you can utilize lipids or fatty acids as an energy source instead.
This activity spares the glycogen stores and keeps fueling your workout.
So, using up the fatty acids instead of glycogen earlier on in the workout lets them be stored for later use. This mechanism helps to delay the onset of fatigue.
6. Astaxanthin Improves Joint Health
The first line of treatment for most people suffering from joint pain is using painkillers.
However, these can soon become addictive and present plenty of negative side effects.
Research in this field suggests that a potential answer lies in astaxanthin.
Given its powerful anti-inflammatory potential, its use has grown in popularity with medical evidence supporting its benefits.
Working somewhat along similar lines as fish oil, astaxanthin seems to target joint pain, stiffness and mobility problems associated with the two most common types of arthritis including osteoarthritis and rheumatoid arthritis.
The anti-inflammatory properties of this carotenoid reduce joint swelling and pain.
For osteoarthritis patients, this may mean relief from the associated pain and tenderness of the condition while improving flexibility.
For rheumatoid arthritis sufferers, relief also centers on reduced inflammation and some pain relief. Although both conditions are non-reversible, using astaxanthin may help with symptom management.
Other similar conditions that may benefit from astaxanthin supplementation include carpal tunnel syndrome.
7. Astaxanthin Helps With Improving Our Vision
Age-associated vision problems like cataracts, glaucoma and macular degeneration are commonplace and can cause a number of uncomfortable symptoms like blurry vision to a complete loss of vision.
Supplementing with astaxanthin can help improve eye health. It can work to protect retinal cells against oxidative damage as well as against eye fatigue and strain.
8. Astaxanthin Offers Immune Support
The immune system slowly loses its potential to manufacture protective antibodies as it ages. At the same time, it also develops a tendency to produce adverse autoimmune reactions.
To counter this effect with antioxidant activity, astaxanthin boosts the bodily generation of antibodies as a response to foreign microbes. It also modifies the manner in which immune system cells react to foreign invasions.