Bladderwrack (Thyroid Support)

A seaweed rich in natural iodine traditionally used to support thyroid function.

Also known as: Fucus vesiculosus • Kelp • Sea Oak

other Names
Fucus vesiculosus, Kelp, Sea Oak
primary Benefits
Natural iodine source, thyroid support, mineral-rich
common Dose
500-1000 mg daily
best Form
Standardized extract with known iodine content
timing
With food
safety Rating
Caution (variable iodine content)

Overview

Bladderwrack (Fucus vesiculosus) is a brown seaweed that has been used for centuries as a natural source of iodine for thyroid support. It also contains fucoidan, alginic acid, and other bioactive compounds with anti-inflammatory and antioxidant properties. As a whole-food iodine source, it provides iodine in a matrix of cofactors.

Key Benefits

Natural Iodine Source

Provides iodine in a whole-food matrix with cofactors for thyroid function.

Thyroid Support

Traditional use for supporting underactive thyroid; provides raw material for hormone synthesis.

Mineral Rich

Contains trace minerals including selenium, zinc, and manganese.

Fucoidan Content

Bioactive polysaccharide with anti-inflammatory and immune-modulating properties.

Dosage & How to Take

500-1000 mg daily with known iodine content.

PurposeDoseNotes
Mild thyroid support500 mg/dayCheck iodine content on label
Moderate support500-1000 mg/dayDo not exceed 1100 mcg iodine/day

Best Time to Take

With food.

With or Without Food

Yes, with food.

Forms & Bioavailability

FormAbsorptionBest ForNotes
Standardized CapsulesGoodKnown iodine contentLook for iodine content on label.
Dried SeaweedVariableDietary useIodine content varies widely.

Side Effects & Safety

Common

  • GI discomfort
  • Metallic taste

Rare

  • Thyroid dysfunction from excess iodine
  • Heavy metal contamination

Contraindications

  • Hyperthyroidism
  • Hashimoto's (without selenium)
  • Iodine allergy

Interactions

Thyroid medicationsModerate

Iodine content may alter thyroid hormone levels.

Blood thinnersMild

Fucoidan may have anticoagulant effects.

Scientific Research

2014Thyroid Research

Seaweed and thyroid function

Studies confirm seaweed consumption effectively increases iodine status, but excess intake can cause thyroid dysfunction.

Food Sources

Bladderwrack seaweed itself

Frequently Asked Questions

Medical Disclaimer

This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.