Astaxanthin

Haematococcus pluvialis · 3,3'-dihydroxy-beta,beta-carotene-4,4'-dione

Snapshot

Indications	Contraindications
Skin hydration and elasticity¹ Photoaged skin^{1, 2} Digital eye strain^3–5 Aerobic exercise performance^6–9 C-reactive protein lowering¹⁰ Prediabetes glycemic markers^{11, 12} Polycystic ovary syndrome markers¹³	Pregnancy or nursing¹⁴ Fish allergy¹⁴ Soy allergy¹⁴

Astaxanthin is a red xanthophyll carotenoid made by the microalga Haematococcus pluvialis and also found in yeast, salmon, and shellfish¹⁵. It sits in cell membranes and quenches reactive oxygen species, the antioxidant effect that drives supplementation¹⁶. Uses that follow are skin hydration and photoaging, digital eye strain, and metabolic or inflammatory markers^{2, 3, 10}. Typical users are adults with photoaged skin, heavy screen exposure, or endurance training^{2, 3}.

Evidence varies by use. A meta-analysis of trials found no effect on glucose, lipids, blood pressure, or body weight, apart from higher high-density lipoprotein cholesterol and lower C-reactive protein¹⁰. A 2026 narrative review found preclinical work supports sperm quality, while clinical evidence in men remains limited and heterogeneous¹⁷. Products listing astaxanthin are mostly capsules and softgels; see Form comparison.

Health Canada labels ask for a practitioner's advice before use in pregnancy or breastfeeding¹⁸. United States product labels warn of fish or soy source allergens, and one asks for a doctor's advice first with blood thinners¹⁴.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

76 sources, 66 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources