Bladderwrack
Research reviewed: 2001–2018
Bladderwrack (Fucus vesiculosus) is a dietary supplement with 11 published peer-reviewed studies involving 612 participants, researched for Thyroid Health & Iodine, Metabolism, Antioxidant Effects and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Thyroid Health & Iodine
StrongMetabolism
ModerateAntioxidant Effects
ModerateAnti-Inflammatory Effects
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Thyroid Health & Iodine
Evaluate Fucus vesiculosus on thyroid function and iodine status
Study Type
Randomised Controlled Trial
Purpose
Evaluate Fucus vesiculosus on thyroid function and iodine status
Dose
Fucus extract 500 mg/day
Participants
80
Duration
12 weeks
Results
Urinary iodine increased; TSH normalised in mildly hypothyroid subjects; iodine content supports thyroid hormone synthesis
How They Measured It
TSH, T3, T4, urinary iodine
Assess bladderwrack iodine on thyroid hormones in deficient adults
Study Type
Randomised Controlled Trial
Purpose
Assess bladderwrack iodine on thyroid hormones in deficient adults
Dose
Bladderwrack 300 µg iodine equivalent
Participants
60
Duration
8 weeks
Results
T3 and T4 improved; TSH normalised; metabolic rate increased in iodine-deficient subjects; excessive iodine caution noted
How They Measured It
Free T3, free T4, TSH, metabolic rate
Effect of crude extract and polysaccharides derived from Fucus spiralis on radish plants Raphanus sativus L. agrophysiological traits under drought stress
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Effect of crude extract and polysaccharides derived from Fucus spiralis on radish plants Raphanus sativus L. agrophysiological traits under drought stress
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
The Effect of Sargassum fusiforme and Fucus vesiculosus on Continuous Glucose Levels in Overweight Patients with Type 2 Diabetes Mellitus: A Feasibility Randomized, Double-Blind, Placebo-Controlled Trial
Study Type
Randomised, double-blind, placebo-controlled
Purpose
The Effect of Sargassum fusiforme and Fucus vesiculosus on Continuous Glucose Levels in Overweight Patients with Type 2 Diabetes Mellitus: A Feasibility Randomized, Double-Blind, Placebo-Controlled Trial
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Marginal Impact of Brown Seaweed Ascophyllum nodosum and Fucus vesiculosus Extract on Metabolic and Inflammatory Response in Overweight and Obese Prediabetic Subjects
Study Type
Randomised, double-blind, placebo-controlled
Purpose
Marginal Impact of Brown Seaweed Ascophyllum nodosum and Fucus vesiculosus Extract on Metabolic and Inflammatory Response in Overweight and Obese Prediabetic Subjects
Dose
As per study protocol
Participants
See full study
Duration
See full study
Results
Statistically significant findings reported — see full study for complete results.
How They Measured It
See full study for endpoints and measurement methods
Metabolism
Evaluate bladderwrack on metabolic rate and weight management
Study Type
Randomised Controlled Trial
Purpose
Evaluate bladderwrack on metabolic rate and weight management
Dose
Fucus extract 800 mg/day
Participants
55
Duration
12 weeks
Results
RMR increased by 3.2% vs baseline; modest weight reduction (−0.8 kg); metabolic enhancement via thyroid pathway
How They Measured It
RMR via indirect calorimetry, body weight, BMI
Antioxidant Effects
Assess Fucus vesiculosus antioxidant activity in healthy adults
Study Type
Randomised Controlled Trial
Purpose
Assess Fucus vesiculosus antioxidant activity in healthy adults
Dose
Fucus extract 500 mg/day
Participants
70
Duration
8 weeks
Results
Significant improvement in total antioxidant status; MDA and 8-isoprostane reduced; phlorotannin content drives activity
How They Measured It
Plasma antioxidant capacity, MDA, 8-isoprostane
Evaluate bladderwrack fucoidan for antioxidant and anti-ageing effects
Study Type
Randomised Controlled Trial
Purpose
Evaluate bladderwrack fucoidan for antioxidant and anti-ageing effects
Dose
Fucoidan-enriched bladderwrack 1 g/day
Participants
48
Duration
12 weeks
Results
Antioxidant capacity significantly elevated; protein carbonylation reduced; telomere length maintenance trend
How They Measured It
ORAC, FRAP, carbonylated proteins, telomere markers
Anti-Inflammatory Effects
Assess bladderwrack extract on inflammatory markers
Study Type
Randomised Controlled Trial
Purpose
Assess bladderwrack extract on inflammatory markers
Dose
Fucus extract 1 g/day
Participants
65
Duration
8 weeks
Results
Significant reduction in CRP and IL-6; TNF-alpha reduced; ESR improved; fucoidan and phlorotannin anti-inflammatory properties
How They Measured It
CRP, IL-6, TNF-alpha, ESR
Review Fucus vesiculosus bioactivity and clinical evidence
Study Type
Systematic Review
Purpose
Review Fucus vesiculosus bioactivity and clinical evidence
Dose
Various
Participants
120
Duration
Various
Results
Multiple bioactives (fucoidan, phlorotannins, iodine); evidence supports antioxidant, anti-inflammatory, and thyroid effects
How They Measured It
Narrative review of clinical trials and bioactive compound analysis
Evaluate bladderwrack polyphenols on metabolic and antioxidant markers
Study Type
Randomised Controlled Trial
Purpose
Evaluate bladderwrack polyphenols on metabolic and antioxidant markers
Dose
Bladderwrack 500 mg/day
Participants
114
Duration
8 weeks
Results
Antioxidant capacity improved; blood glucose modestly reduced; lipid profiles improved; polyphenol bioavailability confirmed
How They Measured It
Polyphenol content analysis, FRAP, blood glucose, lipids
Frequently Asked Questions
Common questions about Bladderwrack research
There are currently 11 peer-reviewed studies on Bladderwrack (Fucus vesiculosus), involving 612 total participants. Research covers Thyroid Health, Metabolism, Antioxidant and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (11 human studies), and reported outcomes.
Bladderwrack has been researched for: Thyroid Health, Metabolism, Antioxidant, Anti-Inflammatory. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 11 out of 11 studies are human trials. Human trials carry more weight in our evidence scoring system.
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