Supplement analysis backed by scientific evidence · PT

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Limited evidenceWeight management

Fucoxanthin

A brown-seaweed carotenoid that increases thermogenesis in rodents. Human trials are few and small, and the best-known weight-loss result came from a combination product rather than fucoxanthin alone.

Evidence last reviewed: August 2026

What the science says

  • Body weight and fat Limited evidence

    A randomized trial of Xanthigen, a fucoxanthin plus pomegranate seed oil combination, reported weight and liver fat reductions in obese premenopausal women over 16 weeks. It is a single trial of a combination product, so fucoxanthin's own contribution is unclear.

  • Metabolic markers Limited evidence

    A randomized controlled trial found effects of fucoxanthin on metabolic syndrome measures and insulin sensitivity in a small group. An earlier trial reported HbA1c reductions with fucoxanthin-enriched oil, apparently dependent on a UCP1 genotype.

  • Seaweed intake generally Limited evidence

    A systematic review and meta-analysis of randomized trials of dietary seaweed on obesity-related metabolic status found small and inconsistent effects. Whole-seaweed data do not establish an effect for isolated fucoxanthin.

Dosage & safety

Studied doseHuman trials used roughly 2.4–8 mg/day of fucoxanthin, often within a combination product, for 8–16 weeks. Supplement labels vary widely and frequently overstate content.
SafetyShort-term trials reported no serious adverse effects. Brown seaweed products can carry substantial iodine and sometimes heavy metals, so people with thyroid disease should be cautious and check the source. Avoid in pregnancy and breastfeeding for lack of data.

Scientific references

Where to buy

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