Fucoxanthin
Summary
Fucoxanthin is a carotenoid pigment from brown seaweed. The main weight-loss evidence is one 16-week trial of a fucoxanthin and pomegranate seed oil blend in obese women; other trials are small, combined with other ingredients, or report only before-and-after changes (grade D). It is poorly absorbed from food, and seaweed supplements can contain inorganic arsenic.
Key facts
- A carotenoid pigment found in brown seaweeds and diatoms[9]
- One 16-week RCT of a fucoxanthin + pomegranate seed oil blend in 151 obese women[1]
- From wakame food (6.1 mg/day), blood fucoxanthinol stayed under 1 nmol/L; a 31 mg extract dose peaked at about 44 nmol/L[6][5]
- Pooled carotenoid trials suggested small glucose drops with astaxanthin and fucoxanthin in type 2 diabetes, on very low certainty evidence[7]
- Seaweed supplements tested contained 1.2–31 µg/day of inorganic arsenic[8]
- 4 graded human outcomes on this page
- October 13, 2026
How it works
ProposedFucoxanthin is converted in the gut to fucoxanthinol, the form measured in blood, and taking it with fat or oil may improve absorption. A mouse study linked it to raised UCP1 in white fat, and the 2010 trial reported a rise in resting energy expenditure. These mechanisms are not established in people.[6][5][9][10][1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Weight | Grade D | Improved | RCT · n = 151 · 2010 | 1 row |
| Cognition | Grade D | Mixed | RCT · n = 43 · 2024 | 1 row |
| Liver | Grade D | Improved | RCT · n = 42 · 2021 | 1 row |
| Metabolic health | Grade D | Improved | RCT · n = 28 · 2023 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Body weight and liver fat in obese women (fucoxanthin + pomegranate seed oil) | Improved | Grade D | RCT · n = 151 · 2010 Obese, non-diabetic premenopausal women with or without fatty liver Form: Xanthigen: brown seaweed extract (2.4 mg fucoxanthin) + 300 mg pomegranate seed oil · Dose: Xanthigen-600 (2.4 mg fucoxanthin/day) · Duration: 16 weeks Body weight fell 5.5 kg (fatty-liver group) and 4.9 kg (normal-liver group), with less body and liver fat, lower triglycerides and CRP. Resting energy expenditure rose with fucoxanthin and Xanthigen. | 19840063 (opens PubMed)Source [1] |
| Memory and attention in older adults with self-perceived decline | Mixed | Grade D | RCT · n = 43 · 2024 Physically active adults aged about 64 with perceived memory decline Form: Phaeodactylum tricornutum microalgae extract with fucoxanthin · Dose: 1,100 mg/day extract (8.8 mg fucoxanthin) · Duration: 12 weeks Some memory, attention and reaction-time measures improved or trended better, but most differences were over time rather than between groups. No negative effects on blood panels. | 39275314 (opens PubMed)Source [4] |
| Liver enzymes and fat in fatty liver disease (fucoidan + fucoxanthin) | Improved | Grade D | RCT · n = 42 · 2021 Adults with non-alcoholic fatty liver disease Form: Low-molecular-weight fucoidan plus high-stability fucoxanthin · Dose: Dose not stated in the abstract · Duration: 24 weeks ALT, AST, cholesterol, triglycerides, fasting glucose, HbA1c and liver fat (CAP) scores fell versus placebo. | 33809062 (opens PubMed)Source [3] |
| Weight, blood pressure and insulin secretion in metabolic syndrome | Improved | Grade D | RCT · n = 28 · 2023 Adults with metabolic syndrome Form: Fucoxanthin · Dose: 12 mg/day · Duration: 12 weeks Within the fucoxanthin group, weight (80.6 to 79.2 kg), BMI, waist, systolic and diastolic pressure and triglycerides fell and insulin secretion rose from baseline (P<0.05). The abstract gives no between-group comparison with placebo. | 37405785 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Brown seaweed extract (kombu, wakame, Undaria) | Varies[5][6] | After 31 mg fucoxanthin in kombu extract, its metabolite fucoxanthinol peaked at about 44 nmol/L at 4 hours (half-life about 7 hours). From 6.1 mg/day in wakame food, plasma fucoxanthinol stayed below 1 nmol/L.[5][6] | Tested seaweed supplements contained 1.2–31 µg/day of inorganic arsenic.[8] | Weight and fatty-liver trials (as Xanthigen or with fucoidan) |
| Microalgae extract (Phaeodactylum tricornutum) | Varies[4] | Not reported in the cited abstracts.[4] | No negative effects on clinical blood panels or perceived side effects over 12 weeks.[4] | Cognition in older adults (8.8 mg/day) |
Studied doses
Doses studied in human trials ranged from 1.6–2.4 mg/day of fucoxanthin (in a pomegranate seed oil blend) to 8.8 mg/day in a microalgae extract and 12 mg/day alone, for 12 to 24 weeks. A single 31 mg dose was used in an absorption study.[1][4][2][5]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Arsenic exposure from seaweed products
- Some seaweed-based supplements contained inorganic arsenic at 1.2–31 µg/day.[8]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
- Fucoxanthin mg vs extract mgLabels often list seaweed extract weight; the 2010 blend used 300 mg extract to deliver 2.4 mg fucoxanthin.[1]
- Blend or single ingredientThe weight and fatty-liver trials combined fucoxanthin with pomegranate seed oil or fucoidan.[1][3]
- Studied amountsSingle-ingredient trials used 8.8–12 mg/day.[4][2]
Cost per studied dose, without the sales pitch
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Cost per studied dose
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Frequently asked questions
Does fucoxanthin help you lose weight?
The main evidence is one 16-week trial in which a fucoxanthin and pomegranate seed oil blend cut weight by about 5 kg in obese women. A 12 mg/day trial reported a smaller, within-group drop (about 1.4 kg).[1][2]
Is fucoxanthin well absorbed?
Poorly from food: a week of wakame (6.1 mg/day) left blood levels of its metabolite below 1 nmol/L. A 31 mg extract dose raised it to about 44 nmol/L.[6][5]
Is fucoxanthin safe?
Trials of up to 24 weeks reported no blood-panel problems, but long-term data are lacking, and seaweed supplements can contain inorganic arsenic.[4][8]
Does fucoxanthin lower blood sugar?
Evidence is weak. A pooled analysis of carotenoids found small fasting-glucose drops with astaxanthin and fucoxanthin in type 2 diabetes, on very low certainty evidence.[7]
Sources
- [1]The effects of Xanthigen in the weight management of obese premenopausal women with non-alcoholic fatty liver disease and normal liver fat.. Diabetes Obes Metab, 2010. RCT
- [2]Effect of Fucoxanthin on Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion.. J Med Food, 2023. RCT
- [3]Fucoidan and Fucoxanthin Attenuate Hepatic Steatosis and Inflammation of NAFLD through Modulation of Leptin/Adiponectin Axis.. Mar Drugs, 2021. RCT
- [4]Effects of Supplementation with a Microalgae Extract from Phaeodactylum tricornutum Containing Fucoxanthin on Cognition and Markers of Health in Older Individuals with Perceptions of Cognitive Decline.. Nutrients, 2024. RCT
- [5]Pharmacokinetics of fucoxanthinol in human plasma after the oral administration of kombu extract.. Br J Nutr, 2012. PK-study
- [6]Low bioavailability of dietary epoxyxanthophylls in humans.. Br J Nutr, 2008. PK-study
- [7]Effects of carotenoid supplementation on glycemic control: a systematic review and meta-analysis of randomized clinical trials.. Eur J Clin Nutr, 2025. meta-analysis
- [8]Arsenic speciation and fucoxanthin analysis from seaweed dietary supplements using LC-MS.. J AOAC Int, 2015. observational
- [10]Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues.. Biochem Biophys Res Commun, 2005. animal-study
- [9]Fucoxanthin, a marine carotenoid present in brown seaweeds and diatoms: metabolism and bioactivities relevant to human health.. Mar Drugs, 2011. review
What changed
- Adversarial review pass: every evidence row's numbers re-checked against its abstract (Europe PMC for abstracts PubMed truncates, PMC full text where open), grades checked against the grading rubric, and safety and overclaim wording re-read. Fixes: Metabolic-syndrome row reworded to say the changes are within the fucoxanthin group with no between-group test in the abstract.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Strict second-pass self review (no separate reviewer agent was available for this batch): every PMID re-fetched via esummary and every evidence row, dose and safety line re-read against its abstract or fact sheet. No NIH ODS or NCCIH fact sheet covers fucoxanthin. The 2023 trial is labelled as within-group results because its abstract does not report placebo comparisons; combination-product rows are marked not form-specific. Retraction and erratum flags checked on all PMIDs: none.