Seaweed
Bladderwrack
Also known as: Fucus vesiculosus, Kelp, Rockweed, Black tang
Iodine-rich seaweed traditionally used for thyroid support, but dose is highly variable.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Bladderwrack product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Thorne Daily Greens Plus | 79 B+ | $0.83 |
| 2 | New Chapter Perfect Postnatal Multivitamin | 78 B+ | $0.39 |
| 3 | Terra Origin Healthy Stress Relief | 78 B+ | $0.67 |
| 4 | NOW Foods Liquid Multi - Tropical Orange | 76 B+ | $0.69 |
| 5 | Codeage Amen Sea Moss | 75 B+ | $0.90 |
| 6 | Zhou Nutrition Thyroid Support | 74 B+ | $0.71 |
| 7 | BulkSupplements Kelp Extract Powder | 71 B | $0.03 |
| 8 | Trace Minerals Electrolyte Stamina | 67 B | $1.00 |
| 9 | Terra Origin Digestive Enzyme Capsules | 65 B- | $0.33 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Bladderwrack should I take?
The typical range is Varies widely - often 500-1000mg providing variable iodine. Monitor thyroid if using long-term
When should I take Bladderwrack?
Morning. Either way.
Which form of Bladderwrack is best?
Capsules — Variable content. Other forms in the catalog: Tincture, Dried.
Is Bladderwrack safe?
Commonly reported: GI upset, Metallic taste, Acne. Serious warnings: Variable iodine can cause thyroid dysfunction, Heavy metal contamination risk, Can trigger autoimmune thyroiditis. Watch for heavy metals
Which Bladderwrack supplement scores highest?
Thorne Daily Greens Plus, at 79/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Daily target & upper limit
150 mcg / day · UL 1100 mcgBladderwrack has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Bladderwrack dosage reference →Primary uses
- Natural iodine source
- Thyroid support (traditional)
- Metabolic support
How it works
- Natural iodine source
- Also contains fucoidan
- Traditional thyroid remedy
- Variable iodine makes dosing difficult
Dosage
- Typical range
- Varies widely - often 500-1000mg providing variable iodine
- Timing
- Morning
- With food
- Either way
- Duration
- Monitor thyroid if using long-term
- Special populations
- Those seeking natural iodine source
Forms
- Capsules
- Tincture
- Dried
Safety
Common side effects
- GI upset
- Metallic taste
- Acne
Contraindications
- Hyperthyroidism
- Hashimoto's (variable)
- Heavy metal sensitivity
Products containing Bladderwrack
Top-scoring supplements in our catalog that list Bladderwrack on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Variable iodine content makes dosing unreliable
Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.