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The Three Astaxanthins

Updated: Aug 1, 2023

Haematococcus pluvialis. The red filling is Astaxanthin.

Astaxanthin: why it's crucial to trace the source

Astaxanthin is a carotenoid. This natural pigment is essential for some photosynthetic organisms and is the world’s most potent antioxidant. It has been in the natural food chain for a very long time. Shrimp, salmon, trout, crabs, other shellfish, and even flamingos’ diets include Astaxanthin, which is the reason behind their pink-reddish tones. All these animals obtain their Astaxanthin from the same origin: microalgae. A species called Haematococcus pluvialis is the only source of natural Astaxanthin.

Astaxanthin’s benefits cover a wide range of organs in your body: skin, brain, eyes, joints, muscles, and more. This is due to its ability to penetrate and stay within the cellular membrane and even cross the blood-brain-and-retina barriers, so it can go everywhere to protect from oxidative damage. This means a continuous intake of Astaxanthin will build it up across your body.

Astaxanthin’s chemical and biological natures are very delicate and precise. This is an important characteristic of this beautiful molecule, but there is more to it.

We mentioned that Astaxanthin has been part of the natural food chain for ages. That accounts for natural Astaxanthin only because it can be synthesized from non-natural sources or produced by non-natural processes. There is synthetic Astaxanthin, manufactured from petrochemicals, and bio-synthetic Astaxanthin, derived from yeast fermentation (Phaffia rhodozyma). All these Astaxanthin types share the same chemical formula (C40-H50-O4), with a nuance that makes all the difference: How some molecule components interact with light changes. These slightly different molecules are called optical isomers or enantiomers, and Astaxanthin has 3 of them: 3S-3’S, 3R-3’S, and 3R-3’R. These are defined by the position of the -OH group at both ends of the central carbon chain. Look at the diagram and read the next section to understand this better.


Chirality, isomers and their different origins

Chirality is a non-symmetric molecule's three-dimensional configuration, affecting how it reflects light. This means a chiral molecule has more than one configuration, each called an isomer, as in Astaxanthin.

And why is the direction in which the light is reflected important? Think of a pair of gloves. There are a right and a left one, each almost identical to the other. You can even fit the incorrect glove onto your hand! Although it feels uncomfortable. It fits, but it doesn’t fit. Or better said, it fits but doesn’t work exactly right.

Something similar happens biologically speaking. When two different isomers of a chiral molecule interact with some of the body’s structures, they can have vastly different effects. One might be therapeutical while the other harmful, as is the case of Thalidomide, where one isomer helped with morning sickness in pregnant women. In contrast, the other was ineffective and produced birth defects.

See the table describing the composition of isomers in Natural, Bio-synthetic and Synthetic Astaxanthin.

3S - 3'S

3R - 3'S

3R - 3'R

Natural Astaxanthin




Bio-synthetic Astaxanthin




Synthetic Astaxanthin





Human consumption safety and clinical trials

It is crucial to know that natural Astaxanthin’s safety is clinically proven. On top of the millennia that Astaxanthin has been part of the human food chain through the consumption of seafood, there are various clinical studies which have concluded Astaxanthin is safe to consume for humans even with dosages four times above the daily intake recommendation by the FDA, 12 mg a day. All of these have been conducted using natural Astaxanthin.

There is no information regarding synthetic Astaxanthin's physiological effects and safety in humans, so don’t take any chances. Synthetic Astaxanthin is widely used in animal farms, especially within the aquaculture industry, where the goal is pigmentation, as Astaxanthin is a carotenoid. So, there is pigmentation, but there are no benefits, which aligns with the much less antioxidant potency synthetic Astaxanthin has shown in comparison to natural Astaxanthin (see reference).

Another issue with Astaxanthin from a source different from Haematococcus pluvialis is the high ratio of non-esterified to esterified Astaxanthin content. Esterified Astaxanthin is stable, which is desirable as antioxidants are prone to interact with many different types of molecules, allowing Astaxanthin to maintain its antioxidant capacity until it is accumulated within your body. Non-esterified Astaxanthin is highly unstable and prone to degrade into Canthaxanthin, which is harmful to the eyes in high dosages.

Synthetic Astaxanthin potency reference

Capelli, B., Bagchi, D. & Cysewski, G.R. Synthetic astaxanthin is significantly inferior to algal-based astaxanthin as an antioxidant and may not be suitable as a human nutraceutical supplement. Nutrafoods 12, 145–152 (2013).


Given that Astaxanthin is a delightful antioxidant and a great addition to your supplement intake routine, it is vital to establish the ground level for quality Astaxanthin. You should always take natural Astaxanthin, as Astaxanthin from synthetic and bio-synthetic origins aren’t widely studied for human consumption, have a weaker antioxidant effect and are unstable.

Taking only natural Astaxanthin means protecting yourself with the most potent antioxidant known to humankind, with the safety background provided by nature and clinical studies. This way, you will avoid the intake of unstudied enantiomers that can harm you instead of boosting your health, which is probably the leading cause of taking nutritional supplements.

Stay safe and avoid oxidative damage with natural Astaxanthin such as NatAxtin®, made as nature intended with the full power of the Atacama Desert.

Also, stay tuned. We will develop this topic further in our next blog entry by the end of August. Surprises are coming, so stay tuned and don’t miss the Astaxanthin news!

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