Supplement analysis backed by scientific evidence · PT · ES · DE · FR

← All supplements
Limited evidenceLongevity & antioxidants

Astaxanthin

Astaxanthin is a potent antioxidant in the test tube and it does shift some blood biomarkers, but the changes are small and rarely map onto anything you would notice. Skin photoprotection is the most promising use; the endurance and eye-fatigue claims are weakly supported.

View on iHerb Ships to 180+ countries · welcome discount for new customers

What the science says

  • Small reductions in oxidative stress and inflammation biomarkers Moderate evidence

    A meta-analysis of randomized controlled trials found astaxanthin mildly reduced malondialdehyde and increased superoxide dismutase, with inconsistent effects on CRP and IL-6. The authors described the effects as mild, and no trial has linked these biomarker shifts to clinical outcomes.

  • Protects skin from UV-induced deterioration Limited evidence

    A 16-week randomized double-blind trial in healthy adults found that 4 mg/day astaxanthin reduced the worsening of skin moisture loss and roughness that occurred in the placebo group after UV exposure, suggesting a protective rather than cosmetic-improvement effect. Sample sizes in skin trials are small (typically 20-65 per arm) and several are industry-funded.

  • Improves endurance performance Limited evidence

    Trials in cyclists and runners using 4-12 mg/day have produced mixed and mostly null results on time trial performance and substrate utilization. There is no reliable ergogenic effect at doses used in humans.

  • Reduces eye strain and improves visual function Limited evidence

    Small Japanese trials report improved accommodation and reduced asthenopia at 6 mg/day, but the studies are underpowered, poorly blinded in places, and largely sponsored. This claim should be considered unproven.

Dosage & safety

Studied doseCommon supplement doses are 4-12 mg/day of natural astaxanthin from Haematococcus pluvialis. Skin trials used 4-6 mg/day for 8-16 weeks; biomarker trials used 4-20 mg/day. Take with a fat-containing meal — absorption is poor on an empty stomach.
SafetyWell tolerated at doses up to 12 mg/day in trials lasting months. Reported side effects are minor: red-orange stool discoloration, mild GI upset, and occasionally lowered blood pressure. It has weak 5-alpha-reductase inhibitory activity in vitro, so theoretical hormonal effects at high doses have not been ruled out. May mildly lower blood pressure and inhibit platelet aggregation — caution with antihypertensives and anticoagulants. Avoid synthetic astaxanthin intended for aquaculture feed. Insufficient safety data in pregnancy and lactation.

How to take it

TimingTiming does not matter.
With food?Take it with a fat-containing meal - absorption is poor on an empty stomach.
Worth knowingOnly natural astaxanthin from Haematococcus pluvialis has been tested in people; the synthetic version is aquaculture feed.

Interactions

With medications

  • blood pressure medication

    Astaxanthin can modestly lower blood pressure, which adds to the drug's effect. monitor your blood pressure when you start

  • warfarin, DOACs and antiplatelet drugs

    Astaxanthin inhibits platelet aggregation and may add to bleeding risk. tell your prescriber and stop it before surgery

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

What are the proven benefits of astaxanthin?

Astaxanthin has moderate evidence for mildly reducing some oxidative stress biomarkers, but no trial has linked those shifts to clinical outcomes. Its most promising use is skin photoprotection, where a 16-week trial at 4 mg/day reduced UV-related skin deterioration, though that evidence is limited.

Does astaxanthin improve endurance or exercise performance?

No reliable effect: trials in cyclists and runners using 4-12 mg/day of astaxanthin produced mixed and mostly null results on time trial performance. The evidence for an ergogenic effect is limited.

How much astaxanthin should I take per day?

Common astaxanthin doses are 4-12 mg/day of natural astaxanthin from Haematococcus pluvialis, and skin trials used 4-6 mg/day for 8-16 weeks. Take it with a fat-containing meal, since absorption is poor on an empty stomach.

Does astaxanthin have side effects?

Astaxanthin was well tolerated at up to 12 mg/day in trials lasting months; side effects include red-orange stool, mild stomach upset and occasionally lower blood pressure. It may add to blood pressure medication and anticoagulants, so monitor and stop it before surgery.

Scientific references

Where to buy

Double Wood Supplements, Astaxanthin AstaReal®, 12 mg, 60 Softgels

View on iHerb

Ships to 180+ countries · welcome discount for new customers

Referral link — this site may earn a commission on purchases.

Related in Longevity & antioxidants