Astaxanthin: an antioxidant that can boost physical performance?

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When protecting cells helps push back fatigue

For several years, astaxanthin has attracted growing interest in the fields of sports nutrition and metabolic health. Found naturally in certain microalgae, shrimp, crustaceans and wild salmon, this molecule belongs to the carotenoid family and stands out for its particularly high antioxidant power.

A recent study published in 2025 examined its impact on physical performance, muscle damage and oxidative stress in young adults undertaking an endurance effort. The results are promising, but deserve a critical reading.

Astaxanthin: a red pigment with remarkable biological properties

Astaxanthin is produced naturally by the microalga Haematococcus pluvialis. It then accumulates up the marine food chain, which explains the pink colouring of salmon, shrimp and krill.

Unlike many water-soluble or fat-soluble antioxidants, astaxanthin has a structure capable of crossing cell membranes and positioning itself within them as a genuine protective “bridge”. This feature allows it to efficiently neutralise certain reactive oxygen species (ROS) involved in oxidative stress.

The study: four days of supplementation before a prolonged effort

The researchers compared a group receiving 28 mg of astaxanthin per day for four days with a placebo group.

At the end of this period, participants performed a constant-intensity cycling exercise corresponding to about 75% of their VO₂max, until exhaustion.

The aim was to evaluate:

• physical performance;
• markers of muscle damage;
• oxidative stress;
• inflammation;
• certain metabolic parameters.

A significant improvement in time to exhaustion

The most striking result concerns the duration of the effort.

Participants supplemented with astaxanthin sustained the exercise for about 85 minutes, compared with 72 minutes in the placebo group.

This difference represents nearly 18% improvement in time to exhaustion.

For such a short intervention, the observed effect is impressive and suggests that astaxanthin could help delay the onset of fatigue during prolonged efforts.

Less muscle damage after exercise

The researchers also measured several biomarkers reflecting exercise-induced muscle damage.

Concentrations of creatine kinase (CK) and lactate dehydrogenase (LDH) were lower in the supplemented participants.

These results suggest that the muscle fibres experienced less strain or coped better with the mechanical and metabolic effects of exercise.

In practice, this could translate into better recovery after certain endurance efforts.

A measurable reduction in oxidative stress

The study also shows a decrease in malondialdehyde (MDA), a marker commonly used to assess lipid peroxidation.

When physical effort is intense or prolonged, free radical production rises sharply within the mitochondria. This production contributes to fatigue but can also damage cell membranes.

By reducing this phenomenon, astaxanthin appears to play a protective role with respect to muscle tissue.

No effect on inflammation or energy metabolism

Interestingly, the researchers observed no significant change in:

• CRP;
• TNF-α;
• carbohydrate utilisation;
• lipid utilisation;
• respiratory parameters.

In other words, astaxanthin does not appear to transform the body’s energy engine.

Its action seems more closely linked to cellular protection than to a modification of metabolic pathways.

Why these results must be interpreted with caution

Despite their interest, several important limitations must be highlighted.

A very small sample

The study involves only a small number of participants.

Small samples increase the risk of obtaining spectacular results that will not be reproduced in larger studies.

An extremely short duration

The supplementation lasted only four days.

It is therefore impossible to know whether the observed benefits persist after several weeks or months.

A very specific population

The participants were healthy young adults.

The results cannot be automatically extrapolated to:

• women;
• older adults;
• elite athletes;
• patients with chronic diseases.

Antioxidants: a more complex story than it seems

This study raises a fundamental question in exercise physiology.

For a long time, free radicals were considered enemies to be eliminated.

Today we know that these molecules also play an essential role in adaptation mechanisms.

ROS are notably involved in:

• mitochondrial biogenesis;
• cell signalling;
• training-induced muscle adaptations.

In other words, a certain level of oxidative stress is necessary to trigger performance-improvement mechanisms.

Excessive reduction of these signals could, in some situations, limit long-term adaptations.

This is why researchers are now interested in the notion of balance rather than the mere suppression of free radicals.

Key takeaways

The initial ten-participant trial was an exploratory signal. The 2026 meta-analysis of 24 randomised trials found no significant effect on VO₂max, time-trial performance, or maximal load/power.

Some muscle-damage biomarkers, including CK and LDH, may move favourably, but heterogeneity is substantial. A biomarker change does not establish improved performance.

Revised conclusion: efficacy for improving physical performance is not demonstrated.

Reference

Effect of astaxanthin supplementation on cycling performance, muscle damage biomarkers and oxidative stress in young adults. Journal of the International Society of Sports Nutrition, 2025.